Operating

Nothing is more important for the quick relief of pain related to skin and nail pathologies than skilful operating, and this aspect of podiatric management should never be underestimated or undervalued as it is a factor that will impress the patient with the practitioner’s skill.

Pain during operating should be negligible and almost immediate relief should be provided unless the tissues are inflamed. Essential elements in painless operating are: maximum immobilisation of the area being reduced by correctly applied skin tension; the selection of appropriate scalpels; and the optimum level of reduction of pathological tissue. It is always difficult to define the optimum level of reduction, but the central consideration is to avoid breaking the skin while at the same time avoiding leaving areas of hard skin that will soon act as an irritant. All scalpels and instruments should be sterile (see Ch. 24). When painless reduction of the pathological tissue with scalpels is impossible, as in heloma neurovasculare and verruca pedis, the use of scalpels should be reduced to the minimum in the first instance, with recourse to caustics or keratolytic agents to facilitate the removal of the keratinised layers and to allow further reduction of the lesion on a return visit. Measures to reduce pain while operating may be either a topical application or an injection of a local anaesthetic (see Ch. 20). Topical applications of anaesthetic substances are said to be effective in certain situations, but can take up to 90 minutes to be effective (Elson & Paech 1995).

Protective padding and strapping will assist in relieving any postoperative tenderness.

Medicaments

With the exception of local anaesthetics and a limited range of prescription-only medicines (POM) taken orally, therapeutic preparations used in podiatry are topical applications. They may have a specific function, as in chemical caustics, antifungal agents and antiseptics, but in general they also have a palliative effect.

Topical therapy can be said to provide relief of symptoms and, more importantly, protection while the skin heals. Many of the agents used lack scientific explanation of their mode of action and are employed because they are known to have been effective in previous treatments. The fact that suitable agents are used empirically should not detract from their credibility but encourage the practitioner to establish links that may add to the understanding of their mode of action. The form in which an agent is used, its method of application, the state of the substrate, the site of the lesion and the patient’s state of health are all factors to be considered in the selection of a suitable agent. The paramount concern should be to treat the lesion quickly, using the minimum quantity of medicament to achieve the desired effect.

Long-term use of medicaments should be avoided, as some agents, or the base in which they are delivered, may cause contact dermatitis. Where application over a long time is unavoidable, as in the case of emollients or keratolytics in hyperkeratosis, the practitioner should be aware of this possibility and should minimise the risk by monitoring (and recording changes) and suggesting the use of alternatives.

In the treatment of specific conditions the patient should be advised to follow the treatment regimen and not to supplement, reduce or vary the treatment. The patient should be advised that if the use of a medicament causes any adverse effect then its use should be discontinued and the advice of the practitioner sought.

Dressings

Dressings give an area of protection from friction, pressure and infection. Dressings are normally sterile and are mainly used on areas where the epidermis has been breached. Sterile dry dressings are available in a variety of sizes and packages, and are packed to facilitate the ‘no-touch’ technique. These dressings may be used with a medicament. The availability of environmental and interactive dressings for use on open lesions is worthy of consideration because of the many disadvantages ascribed to traditional dressings.

Padding and strapping

Many foot problems are biomechanical in origin and mechanical therapy has a vital role in their management to correct function. The therapeutic use of padding and strapping covers both short-term treatment with adhesive padding and strapping and long-term management by orthoses with footwear advice, modification to footwear or specialised shoes.

In the short term, adhesive padding, correctly chosen and applied with appropriate strapping, almost invariably gives immediate relief from pain. In many instances, the adhesive padding may be adapted into replaceable, non-adherent, clinical padding until custom-made orthoses have been prescribed and manufactured for the patient.

The long-term use of clinical padding is inefficient in terms of durability and hygiene, and thus it must always be a short-term solution. The combination of clinical padding and then orthoses affords the most effective means of controlling biomechanical disorders. The management process should be carried out with the full understanding and cooperation of the patient. Patient compliance is essential.

Adhesive padding protects by several means: correction, deflection, cushioning, or by removing tensile or shearing stresses from the epidermis and subcutaneous tissues. Corrective padding is normally used when there is sufficient joint function available to realign the joint. It will improve anatomical alignment and reduce or eliminate abnormal stresses. Appropriate strapping is applied with the padding to assist correction. Padding that protects by deflection or cushioning is also adhered by strapping, but in this instance there is little or no alteration to the position of the underlying deformity. The role of strapping is to secure padding closely to the foot in the correct position. Padding or strapping used to remove either shearing or tensile stresses from the epidermis is normally of a thin stretch-type material.

Clinical padding may be applied directly to the foot in adhesive or replaceable form, fitted into the footwear as an insert, or built into a corrective or protective orthosis. The wide range of materials available to the podiatrist provides a choice of thicknesses and densities, from the very firm to the very soft, depending on the therapeutic objective. Firm materials are required for correction of function and deflection of pressure. Softer materials are required to provide shock absorption or cushioning for tissues subjected to abnormal stresses, or where there is atrophy of the subcutaneous tissues due to age, or debilitated by disease, and is subject to trauma and ulceration.

Silicone and thermoplastic materials can also be used as a medium- or long-term measure to follow clinical padding and strapping (see also Ch. 17).

Review periods

Review of progress in clinical practice and the outcome of the review should be recorded in comprehensive notes in the patient’s records, completed at the time of treatment and supplemented, if necessary, by photographs or accurate charting. The management of podiatric conditions is dependent on the practitioner’s ability to assess progress and to modify treatment strategies as required, and unless each stage is clearly recorded this cannot be said to have been achieved.

The length of a review period depends on factors such as patient compliance and the practitioner’s ability to evaluate the information received. Attention must be paid to the legal issues relating to the accurate recording of treatment strategies and updating all changes that have occurred in the patient, including medical disorders and drug therapy.

A change of treatment strategies may be required if there is a change in medical or social history. If there is no improvement in the condition, the podiatrist must reconsider the original treatment strategy, or re-evaluate the diagnosis, and adapt the management strategy or refer to another professional in the medical field, as appropriate. All changes made must be recorded fully.

Case records

Properly maintained case records are of inestimable value in refuting allegations of malpractice. Litigation is an increasingly common fact of life for all practitioners, and the main weapon in the defence of such allegations, after the adherence to proper accepted practice procedures, is the well-maintained clinical case record (Podiatry Now 1999a).

In all cases emphasis must be placed on an accurate and detailed medical history being taken and recorded in full, and updated at each subsequent visit (see Ch. 1).

Case records should be written up immediately after the treatment has been completed, detailing all that has been carried out in the treatment of that patient and listing all the changes that are necessary to update the case record (Podiatry Now 1999b). Time should be allocated for the completion of the record at the end of each episode of episode of care. The format of the record should be adequate for full reporting and abbreviations used only if they are part of an accepted and published norm. Case records should also indicate that informed consent was obtained from the patient or, in the case of a minor, the parent or guardian. The records should be stored in a safe and secure place.

Pathological callus

This should be removed carefully with a suitable scalpel in order that the areas are cleared of thickened stratum corneum. It is considered by some practitioners that callus that produces no discomfort should not be removed. This is referred to as ‘physiological’ callus. Care should be taken to ensure that the patient does not have loss of sensation due to an underlying medical condition, or the formation of ulceration under the area of callus.

A common cause of sensory loss to the feet is diabetes, and if callus is not removed it may lead to breakdown of tissue as a result of compression of underlying blood vessels, leading to a local ischaemia. Conversely, its removal should be carried out in a manner to ensure that the skin is not breached.

Heloma durum (hard corn) of the digits

These occur on the dorsal aspect and apices of the lesser toes, in the nail sulci associated with pressure from the nail plate or at the lateral edge of the nail, particularly of the fifth toe. Because footwear pressure is the initiating factor in the majority of cases, advice in this respect is mandatory. It is essential to eradicate the nucleus with a scalpel at the earliest stage. Enucleation should remove all the keratinised epidermal cells so that the underlying tissue can be restored to a better condition. Enucleation normally can be accomplished at the first visit, provided there is not extreme pain and tenderness. Difficulty in removal due to impacted keratin layers may be facilitated by the application of 5% potassium hydroxide aqueous solution, for its mild keratolytic action, for a few minutes prior to reduction.

Enucleation of the corn may be followed by the application of a mild keratolytic agent. With little underlying fibrofatty tissue, the choice of agents is limited, with those that are more penetrating being contraindicated. If complete reduction of the nucleus has not been achieved with a scalpel, the application of 15–30% salicylic acid ointment in a white soft paraffin may be used. This keratolytic used at the above concentrations will produce a slow and painless structural alteration of keratinised tissue, softening and macerating it. The action of this medicament is slow and cumulative, and for this reason it should be left in situ for a period of 5–7 days and the coagulum completely removed before further treatment is initiated. This treatment may need to be repeated two or three times at weekly intervals to facilitate eradication of the nucleus. Prolonged treatment with salicylic acid may cause dermatitis. Application should be made using a masking plaster to prevent spread of the agent to surrounding tissue. When the application of salicylic acid in ointment form is not practicable, the base may be changed to collodion or spirit, and this can be applied directly to the area by means of an applicator stick without masking the surrounding tissues. This method may also be used in the nail sulcus with low concentrations of the acid. The addition of padding to deflect pressure away from the area in conjunction with footwear advice or modification is necessary. When complete reduction has been achieved, 25% or 50% silver nitrate solution may be applied. This protein precipitant will ‘shrink’ the walls of the cavity, and repeated applications in conjunction with expert scalpel action will return the tissues to normal, provided that compression stress to the area has been eliminated. Thereafter, patients should be encouraged to restore elasticity to the area by the regular use of emollients.

The presence of peripheral neuropathy, vascular insufficiency, impaired immune response or the effects of long-term steroid therapy on healing will make the application of caustics or any medicament with the ability to cause breakdown of tissue undesirable. However, a mild exfoliant such as 10% salicylic acid in collodion can be used to facilitate enucleation, but the patient should be monitored closely.

Electrosurgery (described later in this chapter) can also produce good results with intractable lesions in carefully selected patients.

Heloma durum (hard corns) on the plantar metatarsal area

These are usually chronic in nature and may be associated with common structural deformities such as pes cavus (under the first and fifth metatarsal heads), hallux limitus/rigidus (under the second or fifth metatarsal heads and the interphalangeal joint of the hallux), and hallux abducto valgus (under the second and third metatarsal heads). The chronic nature of these lesions results in fibrotic changes to the underlying dermal tissues because of the inflammation of the tissues as a result of trauma caused by overloading due to abnormal gait patterns. Such lesions may prove difficult to eradicate successfully in the long term because the tissues at the weight-bearing area have lost their elasticity. They will respond to attempts to increase pliability, but the main emphasis in management must be on deflective and protective padding and orthotic therapy, with correction of function where possible.

Silver nitrate or salicylic acid may be used as a caustic treatment in a similar method to that discussed above for digital lesions.

Interdigital heloma

These lesions are evidence of compression occurring between opposing interphalangeal joints due to abnormal digital alignment or to the base of a proximal phalanx pressing on an adjacent metatarsal head with subsequent pressure on the overlying tissues. These lesions may be exacerbated in some cases by hypermobility of the feet and excessive pronation, with consequent constriction of the toes from footwear. Although a lesion may be limited to the 4/5 interdigital space, it should be borne in mind that the causative factor may well be a biomechanical problem in the rearfoot, such as a rearfoot varus, and complete resolution depends on the elimination of the problem, which is not always possible. Interdigital helomas may also be associated with hyperhidrosis, which determines their consistency as hard (heloma durum) or soft (heloma molle), and which, if present, needs to be controlled. Their enucleation requires skilful operating, especially when they are situated in the fourth web space.

Heloma molle respond well to the application of 20% silver nitrate solution following enucleation. As this has the apparent effect of reducing sweat production, it also toughens up the epidermal tissue of the lesion and makes reduction easier on the return visit. Silicone orthodigital splints or interdigital wedges are the most effective form of padding when the lesion is due to pressure from opposing interphalangeal joints. When the lesion is in the web space, realignment of the metatarsal to the base of the opposing phalanx is required.

Vascular and neurovascular heloma

Lesions of this type are found over interphalangeal joints and plantar to the metatarsal heads. They are characterised by the protrusion of vascular and neural structures into the overlying hyperkeratosis and the objective of treatment is to destroy these elements by cautery. The presence of nerve filaments and capillaries close to the surface makes these lesions highly sensitive and liable to bleed. Operating on these lesions is extremely painful and this usually prevents complete reduction. Superficial callus should be reduced without causing haemorrhage but, should this occur, treatment with caustics must be delayed until the wound has healed. Any operating may be assisted by the preoperative application for 5 minutes of 5% potassium hydroxide solution to soften the overlying callus. These lesions often have multiple small nuclei that cause further problems in reduction. A local anaesthetic will be indicated if extensive excision or electrosurgery to the lesion is contemplated, but progressive chemical cautery is the less traumatic treatment. Whichever method is chosen, these lesions are by the nature of their pathology extremely difficult to eradicate.

In vascular lesions, applications of 50% silver nitrate solution, following reduction without haemorrhage, are effective over several weekly visits. This substance may cause intense pain when used for neurovascular corns. Salicylic acid is also of use in lower concentrations (20% or 25% in white soft paraffin) when tissue breakdown is unlikely.

Electrocautery may also be used in the treatment of such lesions. Local impairment of circulation may make its use more problematic, and while early results seem encouraging, longer term evaluation is needed.

Heloma miliare (seed corns)

These lesions are commonly associated with anhidrosis and may appear on any area of the plantar surface of the foot. They are not associated with pressure, and common sites are the medial longitudinal arch and the heel. They often present difficulties in management due to high recurrence rates regardless of a high level of expertise in enucleation. Some authorities suggest that, if pain is not a feature, treatment should consist of control by the application of emollients or urea-containing compounds, such as 10% urea cream, which affects the keratin linkages and increases the moisture content of the epidermal cells. However, success is more likely if the corn is reduced prior to treatment with a medicament. The area can be softened preoperatively with 5% potassium hydroxide. Patients should be advised on the use of emollients for the long-term management.

Palmoplantar hyperkeratosis

This condition and its associated punctate form present problems in management.

The condition produces keratotic thickenings, which can cause severe discomfort and interfere with the gait cycle. When it appears in large plaques surrounded by an inflammation, its operative removal is often limited by the discomfort, which may be minimised by the application of 5% potassium hydroxide solution. This agent also helps when reducing the punctate form by scalpel, but it is seldom possible to remove all the hypertrophic material. In many instances, complete removal causes the patient discomfort for several days following treatment.

The management of this condition consists of simple reduction of the hyperkeratotic areas, and daily use by the patient of emollients, either by rubbing in daily or by occlusion overnight. The use of a cushioning insole often gives added relief from pain.

Digital padding for the lesser toes

In most instances this should be used either to redistribute the pressure from the lesion or to correct toe function. The application of ointments to digital lesions also necessitates the use of appropriate padding to contain the medicament by redirecting the pressure away from the site of the lesion.

The common deformities of the lesser toes are hammer, mallet, clawed, retracted toes and digiti quinti varus. These deformities may be purely local as a result of footwear restricting the functioning of the toes over a period of years, or secondary as a result of rearfoot or forefoot structural pathology.

Regardless of the cause, conditions such as clawed or retracted toes arise because of excessive extension or flexion. In addition, there may be degrees of axial rotation and medial or lateral deviation. Digital padding should be designed to exert maximum correction, because the toes are only rarely fixed and some degree of correction is almost always possible. The correction achieved in the majority of cases is functional and not structural. Permanent correction can take place only when the foot is held in the correct position by ligamentous and muscular action, without any external help. However, in the young, supple foot opportunities for full correction are increased. These conditions do not usually affect one digit in isolation and, although one digit only may be affected with a hard corn, functional correction is obtained in most cases by regarding the middle three toes as one functional unit and, where necessary, correcting and protecting all three simultaneously through one device.

The major element in claw and retracted toes is an imbalance between the extensor and flexor muscles and it is logical to control these elements by combined dorsoplantar splints (Fig. 16.1A,B). This will exert a reciprocal corrective pressure on the deformities. In a full dorsoplantar splint for the middle three toes, the dorsal pad exactly covers the proximal phalanges and controls any excessive flexion. The plantar pad underlies the intermediate and distal phalanges and controls any excessive flexion. Body weight immobilises the plantar pad against the sole of the shoe, and the dorsal pad is held firmly by pressure from the upper of the shoe. The whole splint is securely in contact with the toes, correcting unwanted deviation in the interphalangeal joints, while the metatarsophalangeal joints are left to function normally. If there is limitation, particularly of dorsiflexion, at the metatarsophalangeal joints, then plantar padding is required in addition to the digital padding to hyperextend the digits. This padding takes the form of a metatarsal bar (Fig. 16.2) or a plantar metatarsal pad behind metatarsals two, three and four (Fig. 16.3) to realign the metatarsophalangeal joints and deflect pressure away from the metatarsal heads if they are receiving excessive pressure. In addition, where there is some contracture of soft tissue, exercises or manual stretching should be initiated to encourage an increase in the range of motion.

Figure 16.1 (A) Combined dorsoplantar splint. (B) Adapted combined dorsoplantar splint to obtain deflection from dorsal and apical lesions. (C) Bolster pad for digits 2–4 when correction cannot be achieved. The bolster deflects pressure away from the apices.

Figure 16.2 Metatarsal bar.

Figure 16.3 A 2–4 plantar metatarsal pad which may be placed over the metatarsal heads or immediately proximal to them.

The clinical padding used is firm felt (usually semi-compressed and 3–5 mm in thickness) and held in place with adhesive strapping. A standard format is shown in Fig. 16.1A, but the basic shape can be adapted to deflect pressure from lesions on the dorsal aspect or the apices of the digits (Fig. 16.1B). The plantar pad can be extended as a prop under the fifth toe, or under the proximal phalanx of the hallux to correct hyperextension of the distal phalanx. In addition, the splint can be made replaceable, but as this is not secured to the foot, slippage of the pad may reduce the functional correction. The shape and thickness of each pad is determined by the patient’s footwear, as is the relative degree of correction or protection required.

Felt padding is a short-term measure for these splints, and it is more effective to manufacture them in silicone materials (see Ch. 17). Silicone can be shaped into retaining grooves interdigitally, which controls any axial rotation and medial or lateral deviation of the digits. The digits must be held in the corrected position until the silicone hardens. Because of the need for precision in the sizing and fitting of orthodigital splints, several important points need to be observed when this technique is used:

In fixed deformities of the lesser toes in the older patient the splints are primarily for protection, by deflecting pressure away from dorsal and apical lesions, and they will have no functional correction, although they may prevent further deformity. These pads are of similar dimensions but are shaped to mould to the position of the digits (Fig. 16.1C) and act as a ‘bolster’ on the plantar surface of the digits, removing the pressure from the apices. In children this form of padding should be firm and slightly oversized to ensure maximum correction. Digital photographs are an excellent method of referencing correction.

Single-digit padding is sufficient when there is a fixed hammer or mallet deformity affecting only one digit. The fifth toe is particularly susceptible to pressure on the dorsal aspect from footwear when the digit is subluxated or in an adducted and varus position. Single padding will primarily have a protective role for dorsal, apical or interdigital lesions. These can take the form of oval cavity pads, crescent pads, U-shaped pads (which may be in replaceable form) or props to the plantar surface of the toes, which may be shaped in the form of a crescent at the distal portion to protect lesions (Fig. 16.4). The use of silicone devices should be initiated as soon as possible for the reasons stated above. The material is moulded directly to the foot, and this obviates any need for casting. The surgical option should be considered where feasible.

Figure 16.4 Single-digit padding. (A) Oval cavity pad. (B) Crescent pad. (C) ‘U-pad. (D) Single prop. This padding is generally used to protect a lesion by deflection.

Plantar metatarsal padding

The range of movement in the metatarsophalangeal joints is crucial in determining the therapeutic objective, and consequently the function, shape and material of the padding required. In the presence of chronic fixation, subluxation or dislocation of these joints, plantar metatarsal padding is designed to palliate the consequential overloading of particular metatarsal heads by redistributing the excessive load or by protecting them with a cushioning material. The cushioning effect is important in the elderly when there is atrophy of the fibrofatty pad underlying the metatarsal heads. In cases of mobile toe deformities in which the metatarsal heads are plantar flexed by the retracted phalanges, metatarsal padding assists in correcting the alignment of the affected metatarsophalangeal joint, particularly if combined with the use of digital dorsoplantar splints.

Footwear must be examined prior to the application of any padding and strapping to assess if it will accommodate the increased bulk of any padding and the increased length of the foot, which results when corrective padding is applied. Initially, plantar metatarsal padding is used in its adhesive or replaceable form, but it is readily convertible for long-term use into the more durable form of metatarsal braces, or as one component of an accommodative insole or functional orthosis.

The basic plantar metatarsal pad (Fig. 16.3) is shaped to cover the heads and approximately two-thirds of the shafts of the middle three metatarsals in order that, on weight bearing, they are relatively dorsiflexed, provided they are sufficiently mobile. The shape conforms closely to the underlying metatarsals, avoiding impinging on the first and fifth metatarsal heads, and taking into account variation in the metatarsal formula. The full thickness of the pad lies directly under the metatarsal heads and it is bevelled off from there in all directions, being carefully graduated on its proximal and distal edges to ensure that it is securely adhered without any irregularities to cause discomfort under load. In addition to improving the alignment of the middle three metatarsals, it provides slight deflection away from the first and fifth metatarsal heads and it relieves symptoms of metatarsalgia. The improvement in the position of the clawed or retracted toes needs to be maintained with digital dorsoplantar splints.

With plantar padding, metatarsal strapping is used to control excessive splaying of the forefoot. The strapping encircles the metatarsus immediately behind the first and fifth metatarsal heads, non-stretch material normally being preferred. A half-metatarsal (‘half-met’) strapping may often be sufficient. This leaves the dorsum free, the ends terminating on the dorsum of the first and fifth shafts after traversing the plantar surface. Felt padding should be occluded with strapping by the application of two or three 5 cm wide straps half overlapping each other, the lateral edges covered with ‘side straps’ and with good anchorage to the skin (Fig. 16.5).

Figure 16.5 Strapping for plantar metatarsal padding.

Adaptations of the basic plantar metatarsal pad include single-wing pads (SW/PMP) (Fig. 16.6A), double-wing pads (DW/PMP) (Fig. 16.6B) and U-section cut-outs (U/PMP) (Fig. 16.6C).

Figure 16.6 Plantar metatarsal padding. (A) Single-wing plantar metatarsal pad to the fifth metatarsal head. (B) Double-wing plantar metatarsal pad to the first and fifth metatarsal heads. (C) ‘U-shaped plantar metatarsal pad.

Winged pads are designed to protect either or both of the first and fifth metatarsal heads from overloading. This pad will deflect pressure from the first and fifth metatarsal heads onto the second, third and fourth metatarsal heads and down the shafts. When adhered to the foot, the wing is reverse bevelled, the thickness of the wing fitting immediately around and behind the metatarsal head or heads. For an SW/PMP to the first metatarsal head, the lateral edge of the pad is located over the area between the fourth and fifth metatarsal shafts. The medial edge of a SW/PMP to the fifth metatarsal head is located over the area between the first and second metatarsal shafts. With a medial wing, the overall width of the pad must conform closely to the medial curve of the footwear so that no overlap of full-thickness material on the upper of the shoe is permitted, as this would tighten the vamp. The extra width required for anchorage is well bevelled and moulded around the metatarsal shaft. Full thickness will be under the middle metatarsal heads. This pad can be adapted to increase metatarsophalangeal function by the addition of a metatarsal bar or, if the first and fifth metatarsals are plantar flexed, by the addition of adapted shaft pads to those metatarsals, the distal aspect of the shafts stopping immediately proximal to the metatarsal heads.

The ‘U-section pad is similar to a PMP but is extended across all five metatarsals with the ‘U-shaped section reverse bevelled and cut out over any one of the middle metatarsal heads. The function is to deflect pressure from a particular metatarsal head to the other metatarsal heads and the shafts. A modified shaft pad may also be added behind the U-section to dorsiflex the metatarsal if motion is available. This pad follows the line of the toe webbing, but enough space is left distally to accommodate the strapping and it extends approximately two-thirds of the way down the shafts.

Metatarsal bars (Fig. 16.2) are functionally corrective pads and are designed to realign the metatarsophalangeal joints, increase toe function and deflect some pressure from the metatarsal heads onto the metatarsal shafts. They are ineffective in high-heeled shoes. When adhered to the foot, the distal margin of the pad is reverse bevelled, with the full thickness of the pad fitting immediately behind the metatarsal heads. The pad is contoured to the metatarsal formula and extends two-thirds along the metatarsal shafts. It is adhered with non-stretch occlusive strapping.

Shaft pads (Fig. 16.7) may be used for any metatarsal, although they are most commonly applied to the first, and can be described as either long- or short-shaft pads. Long-shaft pads (Fig. 16.7A) are used almost exclusively to the first metatarsal and extend to the interphalangeal joint where it is normally crescent shaped and reverse bevelled at that point. The purpose of a long-shaft pad is to increase the weight bearing through the metatarsal head, limit motion at the metatarsophalangeal joint and deflect pressure away from the interphalangeal joint. They are used in hallux limitus/rigidus. Short-shaft pads (Fig. 16.7B) stop distal to the metatarsal heads, the convex contour mimicking the metatarsal head with the full thickness of the pad lying directly over the metatarsal head. They are designed to increase the load to a particular metatarsal and realign the metatarsophalangeal joint. Perhaps the most common use is with a first metatarsal that is incompetent. They are used in conjunction with interdigital wedges to treat interdigital corns in the web space.

Figure 16.7 Shaft pads. (A) Long-shaft pad to the first metatarsal and proximal phalanx. (B) Short-shaft pad to the first metatarsal.

The treatment of verrucae

The principal measures are centred on cell-destruction techniques. These include chemical cautery, cryotherapy and electrosurgery. There has been some interest in techniques to produce cell-mediated immunity. In some instances, interactive dressings, astringents and homeopathic remedies are used when possible tissue breakdown is not desirable, as in the case of the ‘at-risk’ patient. A number of practitioners are using actual cautery or curettage with promising results.

Chemical cautery

This retains an important place in the treatment of verrucae, and produces rapid results with minimal discomfort to the patient. Fundamentally, the acids are designed to irritate the skin at the level of the dermoepidermal junction, thus separating the verruca from the skin.

The fact should be clearly established with the patient before treatment that chemical therapy can, and usually does, cause pain, and may result in tissue breakdown. It should be emphasised that, while such symptoms can be upsetting, they are not a sign of the treatment having gone wrong and can be dealt with swiftly and effectively by the practitioner who applied the caustic substance. The stronger acids such as monochloroacetic acid and pyrogallic acid are particularly liable to cause tissue breakdown and pain. Although these acids can be accurately confined to the lesion on initial contact, whether in ointment or solution form, when absorption into the tissues occurs there is less control over spread or depth (Fig. 16.8). Extreme care and good clinical judgement should be employed by the practitioner in the application of these agents.

Figure 16.8 Absorption of acid into the tissues (arrows show directions of spread). Although the application of the medicament is controlled at the surface, spread cannot be controlled through the tissues.

The substances available for use include various preparations of salicylic acid, monochloroacetic acid, trichloroacetic acid and potassium hydroxide, their caustic actions being strictly confined on application to the verruca tissue. The use of substances such as nitric acid and pyrogallic acid has largely been discontinued. The choice of agent depends on a number of factors, as each agent has a different action and penetration potential. When applying any caustic agent it cannot be overemphasised that the patient must be supplied with comprehensive written instructions regarding what to do should there be an adverse reaction.

Site. A lesion on a non-weight-bearing area is usually superficial, so liquid caustics are useful (e.g. salicylic acid preparations in collodion, trichloroacetic acid solution or a saturated solution of monochloroacetic acid used sparingly) are useful.

A verruca on a weight-bearing area is deeper as the weight of the patient and the resistance of the ground push the verruca below the surface, and thus both liquid and ointment preparations are suitable. Care must be exercised in the use of caustics where there is little underlying adipose tissue in order to avoid causing a severe tissue breakdown or producing an inflammatory reaction in an underlying joint. In such a situation, less penetrating caustics or strong astringents are indicated.

In certain cases, where the verruca is on a site unsuitable for padding, treatments involving ointments cannot be carried out.

Number and size. This influences the form and strength of the medicament to be used. Large verrucae respond well to ointment preparations. However, when numerous growths are present, masking is difficult. A large growth surrounded by smaller satellites may be treated with 60–75% salicylic acid ointment, and the satellites either ignored or treated with toughened silver nitrate alone or in conjunction with trichloroacetic acid. In general, caustic in ointment form or in solution is indicated for one or more large growths, while multiple small verrucae are more easily treated with solutions. Cryotherapy or electrotherapy offer alternative single treatments for any type of verruca.

Skin texture. If the skin is moist, solutions of caustics are preferable, as there is no necessity to confine them within padding, which would be contraindicated in the presence of hyperhidrosis. Fair-skinned people seem to be less tolerant of the action of some acids and often react adversely to silver nitrate. Tissues that are thin, dry and atrophied due to age or a systemic disorder do not tolerate acids and are liable to breakdown.

Circulation. When the arterial supply is reduced, as in the case of diabetes or atherosclerosis, ulceration of the area must be avoided because healing is delayed and bacterial infection could supervene. For the same reasons, similar care must be taken to avoid ulceration in the case of impaired venous circulation, which results in the tissues being oedematous. In such instances, caustics should be avoided and astringents or mild keratolytic agents employed.

Neuropathy. An inability to experience pain is a contraindication to any medicament likely to cause an inflammatory action or tissue breakdown. In such cases astringents or mild keratolytic agents should be employed.

Availability of patient. When powerful acids are used, it is essential to ensure that the patient is able to return within 7 days or at a time sooner if considered necessary by the practitioner. Otherwise, use an alternative form of treatment such as cryotherapy or one of the other ‘one-off’ treatments. A final option would be one of the mild keratolytic agents. The use of home treatments is another possibility, provided the patient will adhere to the treatment regimen.

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Age. Young children are often nervous, as well as seeming to have low pain thresholds. Their skin tends to be hyperhidrotic and they are normally very active, engaging in swimming or various other sporting activities. Their involvement in the latter areas usually means that ‘one-off’ solutions have to be used.

Previous treatments. The practitioner should establish which medicaments have been used previously in order to reduce the risk of continuing a non-effective treatment or a treatment where there has been an adverse reaction. A history of treatment that has not cleared the condition usually predicts that the verruca will be slow in responding to treatment.

All of the above must be taken into account when deciding on the preferred method of treatment. Ointments or pastes will spread to normal surface tissue unless contained by masking of the adjacent healthy tissue. The surrounding skin should be painted with substances such as tincture of benzoin compound or Opsite™. The area should be masked with thick waterproof adhesive plaster through which a hole has been cut slightly smaller than the surface area of the verruca. (A light application of silver nitrate to the periphery of the lesion using a silver nitrate stick (95% or 75%) prior to the application of the masking tape gives added protection from lateral penetration of the tissues by the caustic.) The ointment is then applied through the hole in the plaster to the verruca and sealed in with waterproof strapping to ensure close contact. Estimating the amount of the agent to be applied is always a matter of judgement, but it is important that the amount is not excessive, encouraging it to spread laterally. Alternatively, if more medicament is required after the initial masking tape is in position a felt pad with an aperture of the same size is placed over the verruca and the ointment placed into the aperture to the required amount, which will help to contain the ointment. If the first method is adopted, then padding with a cavity to deflect pressure away from the area of the verruca and relieve pain should be applied, particularly if the lesion is on a weight-bearing area. The padding should then be covered totally with zinc oxide plaster, left in position for up to 7 days and the patient advised to keep the whole area dry to prevent spread of the acid (Fig. 16.9).

Figure 16.9 Masking of the tissues to limit the contact area of the acid. Padding and occlusive strapping are used in the application of ointments in the treatment of verrucae.

An instruction sheet must be given and explained to patients receiving verruca treatment (see Ch. 27). The information should include issues of hygiene while keeping the dressing and the area dry, the method of treatment used, specific instructions relating to any antidote to the medicament applied, what to do in case of pain from breakdown of tissue, emergency telephone numbers, etc.

At subsequent visits, the necrosed tissue is removed under strict antiseptic conditions. It is unlikely that one application will have resolved the substance of the verruca and subsequent applications of the caustic should be made and repeated as necessary until complete resolution has been achieved. The state of the skin should be taken into account when continuous treatments are required, as maceration, either with the spread of salicylic preparations or with continual application of plaster to the skin, may require a different approach for a period of time.

As stated earlier, the objective of treatment with acids is to produce an aseptic necrosis and resultant sloughing of the verruca tissue. With carefully controlled dosages and spacing of treatments, this should be a relatively pain-free process.

If tissue breakdown does occur, further applications of an acid should be stopped until healing has occurred. The ulcer should be treated appropriately with a suitable antiseptic agent to prevent infection, or with a sterile dressing, and the patient advised not to remove the dressing. Deflective padding should be applied to remove direct pressure on the area. The patient should be seen at frequent intervals until the pain and inflammation subsides which, as it is aseptic in origin, should be rapid. It is important to monitor the patient well at this stage, as there have been many examples where the patient has considered their painful problem was not being well managed and sought advice from other sources. Such interventions usually result in the lesion being misdiagnosed and inappropriate treatments being applied.

Single-treatment techniques

These treatments have become more common in the management of verrucae, mainly as a result of improved apparatus, particularly in the cases of cryotherapy and electrosurgery. Such methods produce results quicker in all but the most intransigent lesions, and the function of the return appointments is to monitor and evaluate the success of the treatment and, if necessary, to dress any ulceration that has arisen as a result of the treatment. Although classed as single-treatment techniques, there is no absolute guarantee that resolution will be achieved in one session, and caution should be exercised when describing them as such to patients.

Single-treatment techniques are:

Electrosurgery and radiosurgery using cutting, coagulation, desiccation and fulguration

Electrosurgery is the use of electrical energy in the form of a high-frequency current applied locally with a metal instrument for the removal or destruction of tissue (Stedman 1990).

The term ‘radiosurgery’ is also sometimes used to describe electrosurgical treatment. This is because some machines operate at a radiowave frequency.

Background

It may have been in Ancient Egypt that heat was first used to control bleeding. Throughout history, heated metal instruments have been used to destroy tissue and stop haemorrhage. While early instruments were heated on a fire for cauterisation of tissue, the development of tools heated by an electric current enabled greater control. This is known as electrocautery. Instruments currently used for electrocautery consist of a handpiece with switch and platinum wire electrode. With the advent of machines to produce an alternating and high-frequency current, it became possible to cut and coagulate tissue using the principles of diathermy (Brown 2000, Sebben 1988b). Standard diathermy is based on the principle of two large thin plates (electrodes) being placed on the body over the treatment area. A high-frequency electric current is passed to the patient, and tissue resistance results in local heating. Standard diathermy causes mild local heating, as the heat is dispersed over the large area of the electrodes. Electrosurgical machines also operate on the principle of diathermy, but one of the large electrodes is replaced by a small electrode. While the same current is applied to both electrodes, it has a higher concentration in the small electrode. Resistance of body tissue to the electrical energy causes an increase in molecular heat. This results in evaporation of the cell fluids, and destruction of the tissue (Cresswell 1992) (Fig 16.10).

Figure 16.10 Methods of applying current.

For several decades, electrosurgery has been a popular treatment modality amongst dermatologists and other medical specialists (Sebben 1989). Podiatrists have also recognised the advantages of using electrosurgery to perform a number of minor surgical procedures, and electrosurgical units are now a well-established tool in many podiatry clinics. Electrosurgery is frequently used in podiatry for the treatment of cutaneous lesions. Research has shown that electrodesiccation is a successful method of treating chronic corns (Anderson & Burrow 2001, Whinfield & Forster 1998, Wilkinson & Kilmartin 1998). Investigators have demonstrated electrosurgery to be a useful treatment option for removal of resistant verrucae (Lelliott & Robinson 1999, Valinsky et al 1990, Wyre & Stolar 1977). Electrosurgery may be used to destroy the nail matrix after nail surgery procedures. Anecdotal evidence indicates there is less postoperative pain and a faster healing time with electrosurgery compared to some other methods such as phenolisation. One study reported a success rate of over 98% after 73 matrixectomy procedures were carried out using radio wave correction; there were no incidences of regrowth or postoperative discomfort (Hettinger et al 1991, Zuber 2002). Training and practice in the technique, as well as standardisation of treatment parameters, are thought to be important factors in achieving good results (Zuber 2002). Further controlled trials are needed to determine the long-term effectiveness of this procedure.

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Electrosurgical physics

An understanding of electrophysical principles is necessary in order for the practitioner to make safe and optimum use of electrosurgery.

The effect of applying electrical current to tissue is modified by changes to the:

• frequency

• current

• waveform

• shape and size of the electrode(s).

Frequency. The energy required to perform electrosurgery is provided by a high-frequency alternating current. High-frequency currents set up alternating electrical fields of electromagnetic waves that switch so rapidly that there is no time for the actual flow of electrons. A rapid ‘to-and-fro motion of molecules is thus produced (Sebben 1988a). When in contact with body tissue, friction from the tissue’s resistance to this motion results in the residual effect of the production of heat. The effect on the tissues will vary according to the frequency level. The use of frequencies below 500 kHz results in muscle contraction or electric shock, known as the faradic effect. As the frequency increases, this effect begins to disappear. Electrosurgery units vary in the frequency level at which they operate; the exact frequency obtainable is specific to each machine. To cut tissue, an optimum frequency level of 3.8 MHz has been recommended (Maness 1978). Electrosurgery units operating within this spectrum convert electrical current into controlled energy in the radiowave frequency (Brown 2000, Ellman International Inc 2007, Niamtu 2001). The term radiosurgery is often used for treatment using these wavelengths. Radiofrequency waveforms do not cause a faradic effect (Hettinger 1997). The chart shows a range of electrical frequencies and their respective uses (Fig 16.11).

Figure 16.11 Range and Uses of Electrical Frequencies.

Current. For most procedures, a low current at high voltage is passed to the patient through the electrodes. Altering the voltage or amperage will affect the amount and depth of heating. When current passes through tissue with a high resistance, such as muscle, a greater heating effect will result than when it is applied to tissue with a low resistance, such as bone (Bennett 1988). The heating effect also increases with the amount of time for which the current is applied.

Waveform. Electrosurgery units produce an oscillating wave known as a sine wave (Sebben 1989). Pure sine waves are described as a continuous, regular oscillation of electromagnetic energy (Sebben 1988b). The focused oscillations of a pure sine wave are used for tissue section or cutting. This waveform gives the least lateral heat and least tissue damage. A damped (also known as rectified) wave can be described as intermittent pulses of voltage that rapidly return to zero after each burst of activity. The intervals between each pulse can be varied to produce different degrees of damping. Slightly damped, or blended, waves may be used for cutting with coagulation. Markedly damped waves are required for fulguration (spark gap or hyfrecation), desiccation and coagulation, in which more lateral heat is produced (Fig 16.12).

Figure 16.12 Waveforms.

Electrode selection. Electrosurgery units often require two electrodes to complete the circuit. One emits the current (emitting electrode) and one disperses the current (dispersive electrode) (Sebben 1989). To destroy tissue, a small emitting electrode or probe is used to concentrate the heating effect. The smaller the area of the probe applied the greater the tissue damage. The dispersive electrode is placed in contact with the patient. It carries the same amount of current as the emitting electrode, and must therefore be relatively large to prevent unwanted tissue damage. It also offers a return pathway of least resistance should the equipment malfunction or the patient touch a conductive surface during the procedure. Electrosurgery units operating at the higher and radiowave frequencies do not require a dispersal plate. The use of an antenna is usually recommended for optimum effectiveness. This acts as an aerial and concentrates energy at the operating area. Contact of the antenna with the patient is not required as it is not a grounding plate, and there is no opportunity to shock or burn the patient (Niamtu 2001). There is no danger if the antenna plate is not used, but power settings may need to be increased (Hettinger 1997). The heating effect created at high frequencies occurs in the tissues only, so when it is in use the active electrode remains cold (Brown 1995).

Equipment

Spark-gap generators were the first instruments to use high-frequency alternating currents. They produced a spark that burnt the surface of the tissue to produce the superficial charring known as hyfrecation.

Today a wide range of electrosurgical units is available. Many of them are small, portable units suited to small surgery use. Some machines are suitable for desiccation, fulguration and coagulation, but cannot be used to cut tissue. For those professionals who do not wish to use a cutting current, these lower power units may best serve their needs (Sebben 1988b). Electrosurgical units operating at radiowave frequencies are designed to perform a range of procedures and may be used to successfully cut, desiccate and coagulate tissue (Ellman International Inc 2007).

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Active electrodes (probes) are usually supplied with the machine but they can also be purchased separately. Various shapes and sizes are available, facilitating a range of procedures. For example: needle electrodes to make incisions, loop electrodes for excising tissue, ball electrodes for coagulation and desiccation, rod electrodes for fulguration and desiccation, and matrixectomy electrodes for desiccation of the nail matrix. Matrixectomy electrodes consist of a narrow flat plate, the upper side being insulated to prevent damage to the proximal nail fold (Brown 2000). Probes are available in disposable, sterile packs, or as reusable items that can be sterilised.

When a high-frequency current is passed through the electrode, the electrode remains sterile and thus should not become contaminated during use. (Brown 2000, Ellman International Inc 2007). However, Bennett and Kraffert (1990) have suggested that bacterial transfer could take place from one patient to another via the electrodes. Active electrodes should be either disposable or designed for re-use with standard sterilisation techniques such as autoclaving.

Operation of the unit may be either by a foot pedal or a button on the handpiece. Some handpieces can be treated with gas sterilisation. Alternatively, surgeons may employ single-use disposable coverings or gauze to maintain sterility of procedure (Broughton & Spencer 1987).

It is important to follow the manufacturer’s advice with regard to the use of electrosurgical units, due to the number of different machines available and the variation in safety and operational requirements between them.

Safety

When used correctly, electrosurgery is a safe procedure. The main dangers during use of an electrosurgical unit are from the rare occurrence of unintentional grounding, burns and the risk of explosion. Unintentional grounding can be avoided by good use of the dispersal electrode and the removal of metal objects from the work area. The patient’s chair should not contain metal that could be easily touched during treatment. Work trolleys should have glass or plastic surfaces.

Burns may occur if the dispersal plate is poorly applied, the patient has metal implants or there is intense scar tissue between the plate and the leg. The danger is much less in podiatry, where anaesthesia is local and the patient is conscious. If a patient complains of heating anywhere in the body, treatment should be stopped until the source has been found and the problem solved.

Although emergency equipment should be available in case of accident, pressurised cylinders such as oxygen should not be kept in the room where electrosurgery is being carried out.

If the preoperative antiseptic contains alcohol the skin surface should be completely dry before applying the activated probe. Failure to do this will cause the residual alcohol on the skin to ignite, which may alarm the patient.

Patient selection

With few exceptions, local infiltration or nerve blockade anaesthesia is required before treatment. Care must therefore be taken to ensure that patients are suitable for the administration of local anaesthetics. As a wound is created, desiccation of a corn or verruca is not recommended where healing is severely compromised. Electrosurgery should not be carried out if the patient has a metal implant between the lesion to be treated and the site of the dispersal plate. Where the manufacturer does not advocate the use of a dispersal plate, their advice should be sought before proceeding. Caution is advised when operating in very close proximity to bone tissue, due to its high conductivity (Ellman International Inc 2007). Consideration should be given to the potential risk of interference with pacemakers. Modern pacemakers are considered safe from the effects of electrosurgery, but advice should be sought from the patient’s medical consultant before treatment is given.

Procedures

Before undertaking electrosurgical procedures the technique has to be learned, and it is advisable that an individual using the technique for the first time undertakes training. It is also important to note that individual manufacturer’s instructions may vary slightly and adaptations to the procedure should be made accordingly.

Cutting. To cut tissue, an undamped or mildly damped current with a very fine emitting electrode is used (Sebben 1989). Cutting current is a valuable tool for surgical procedures due to its speed, efficiency and lack of trauma to the surrounding tissues (Hettinger 1997).

While tissue section can be carried out with some lower power electrosurgery machines, most successful results will be achieved with a unit that provides the optimum cutting frequency of 3.8 MHz. Modern radiosurgery machines using a pure filtered waveform operating at this frequency can generate several different waveforms (Ellman International Inc 2007). To cut tissue, no pressure is required as cells are vaporised in the path of the radiowaves, causing them to split apart. Use of a wire or loop electrode to incise tissue therefore results in less trauma to surrounding tissues than does the use of a cold scalpel (Brown 2000).

In podiatry, loop or wire electrodes are a popular choice for removal of unwanted lesions such as verrucae, skin tags, cysts, benign growths, hypergranulation tissue or pyogenic granuloma. The operator can control the amount of tissue removed and, where bleeding is a problem, can modify the waveform to produce a small amount of lateral heat to coagulate small blood vessels whilst cutting.

Unlike desiccated or fulgurated tissue, lesions that have been removed using this procedure can be sent for histological analysis.

Fulguration. The word fulguration derives from the Latin ‘fulgur’, which means lightning. For electrofulguration, a high voltage damped waveform is used. If the electrode is activated whilst held just above the skin surface, a stream of sparks can be drawn from the electrode to the point of treatment. This produces a superficial charring of the tissues. Tissue damage is shallower than with desiccation, as the superficial carbonisation acts as a barrier insulating the tissue from deeper current penetration. The wound therefore tends to heal very quickly (Laughlin & Dudley 1992). The electrode should be precisely positioned to avoid an electrical ‘arc’ being diverted to adjacent tissue areas with higher conductivity or to metal instruments. The amount and depth of tissue destruction is dependent on current intensity, length of time of application, the density and the moisture content of tissue, and distance of the electrode from the operating area.

Fulguration is sometimes used for destruction of verrucae and is a useful method for removing shallow skin lesions. If a lesion is destroyed with fulguration, it cannot be examined histologically, unless a preliminary biopsy is taken.

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Desiccation. The word desiccation is from the Latin ‘desiccare’, meaning to dry. An intermittent, damped waveform with a relatively high voltage and low current is used (Sebben 1989). Heating within the tissues causes the water in the cells to evaporate, leaving them shrunken, shrivelled and with nuclei condensed and elongated (Bennett 1988). Low power settings confine the damage to the upper layers of skin, and result in separation at the dermoepidermal junction (Hainer 1991a,b, Sebben 1988b, 1989). Desiccated tissue has a ‘white cap’ appearance. Scarring is usually absent or minimal, although higher power settings may result in some scarring due to damage to deeper tissues (Hainer 1991a,b, Sebben 1988b, 1989). The probe is held in contact with the skin, causing a radial spread of current. Electrodesiccation and fulguration may occur simultaneously to some extent, depending on the application. Use of some machines that employ a high voltage can result in superficial charring due to arcing, particularly around areas of high resistance as the current ‘jumps’ to tissue with a higher conductive capacity (Broughton & Spencer 1987). It is advisable to keep the treatment area moistened with sterile saline solution. Most modern units are designed to enable electrodesiccation to take place without the problem of arcing.

Desiccation is an excellent treatment for the destruction of unwanted lesions such as chronic corns and verrucae. As with fulguration, once desiccated the lesion cannot be examined histologically unless a preliminary biopsy is performed.

CASE STUDY 16.3 MANAGEMENT OF CHRONIC HARD CORN

A 43-year-old male taxi driver was referred to the advanced therapy clinic. He reported a 7-year history of recurrent pain associated with a hard corn in the ball of his left foot. The symptoms were most severe when he was standing, walking or driving his taxi cab. Regular scalpel enucleation of the corn at his local podiatry clinic afforded temporary relief of pain, but had failed to resolve the problem. He had received footcare advice. His footwear was satisfactory and he was wearing the recommended cushioning insole. The patient was keen to find a longer term solution to the problem.

On examination, a lesion consisting of callus overlying a central hard corn was present on the plantar surface of the left foot over the third metatarsophalangeal joint. The area was sensitive to firm pressure. There was no obvious functional or biomechanical abnormality. The patient was in good general health, and his medical history was unremarkable. He was not taking any medication.

The procedure for electrodesiccation was explained to the patient. He was given written information about the treatment and a postoperative advice sheet.

PROCEDURE

On the day of surgery, a tibial block was administered, using 2 ml mepivacaine hydrochloride. Whilst awaiting anaesthesia, overlying callus was reduced and any remaining corn tissue enucleated. Desiccation was carried out using a 2 mm ball probe. The section of desiccated tissue (approximately 7 mm × 5 mm × 4 mm) was removed. The wound was dressed and the patient was advised to rest the foot for 48 hours.

3 DAYS POSTOPERATIVELY

The patient admitted he had returned to work 2 days after treatment due to staff shortage. Despite the additional trauma to the wound, he had felt only mild postoperative discomfort. The wound was clean.

4 WEEKS AFTER SURGERY

A slight eschar had formed over the wound and this was debrided with a scalpel.

6 WEEKS AFTER SURGERY

The wound was fully healed. The patient stated that he could walk and drive without discomfort.

REVIEW AT 6 MONTHS

A thin layer of callus was present over the area that had been treated. This was asymptomatic. The patient was pain-free and he stated he was ‘highly satisfied’ with the electrodesiccation treatment.

Coagulation. The term coagulation derives from the Latin term ‘coagulare’, meaning to clot. It is achieved electrosurgically using a current relatively lower in voltage and higher in amperage than for desiccation. The intermittent, damped current and a larger emitting electrode produce less intense heat over a larger area (Sebben 1989). The mass temperature created in the tissue cells is sufficiently high to cause coagulation of cell protein.

Ball or flat probes are often used to coagulate small blood vessels and stop bleeding, with the electrode held in light contact with the area to be coagulated. The method is often used for haemostasis of small blood vessels during and after surgical procedures such as cutting or desiccation.

Very precise haemostasis may be obtained by using bipolar forceps. Each forcep blade is connected to the radiosurgical unit so that the current passes between the two blades. This may be useful in microsurgery to coagulate individual vessels.

Electrosurgical treatment of verrucae

Verrucae can be removed by cutting with a loop electrode, or desiccated using the procedure described for desiccation of chronic corns (see below).

The use of high-frequency radiosurgery units is recommended for optimum cutting results. When excising a verruca using a loop electrode, a rapid, smooth, ‘sweeping’ movement with the loop can effectively peel off progressive layers of the epidermis. The operator can control the depth and area of treatment, and thus remove selected areas of diseased tissue (Fig 16.13). A ball probe and lower setting may then be used where haemostasis is required.

Figure 16.13 Placement of loop electrode to cut/coagulate lesion (e.g. verruca).

Nail bed ablation

Excellent results have been reported using radiosurgery for ablation of the germinal nail matrix. The technique is similar to that used with phenolisation, except that the matrix is destroyed electrically (Brown 2000). The procedure is facilitated by using a specially designed matrixectomy electrode that is insulated on one side to prevent damage to the overlying eponychium. The tourniquet remains in place following partial or total nail avulsion. Using the setting recommended by the unit manufacturer, the probe is held lightly over the nail bed and activated for 2–4 seconds. The probe is moved and the process is repeated until all areas of the germinal epithelium have been treated. Normally bleeding is not a problem, due to the desiccating effect. Patient preparation, safety precautions and postoperative care are carried out as for other electrosurgical and nail surgery procedures (Fig 16.14).

Figure 16.14 Placement of the dorsally insulated matrixectomy electrode.

Suggested procedure for desiccation of heloma durum (hard corn)

A suggested procedure for electrodesiccation of a corn is set out below. Success in this technique depends on accurate treatment of the lesion. It is advisable that the individual using the technique for the first time undertakes training. Poor results may be due to the formation of excessive scar tissue through improper use of the machine, and to incomplete desiccation.

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1. The procedure is explained to the patient and a written information sheet regarding postoperative management provided. Jewellery and rings, especially those near the operative site, should be removed. A local anaesthetic is administered. Local infiltration is generally adequate, but for plantar lesions a tibial blockade may be preferable. Overlying callus or corn is reduced with a scalpel.

2. A suitable probe is selected. For the dense nucleus of a small corn a 2-mm ball probe is appropriate. A larger probe is more suitable for peripheral callus or larger lesions. Probes may be changed during the procedure, but the machine should be switched off when doing so.

3. If a dispersal plate is recommended by the manufacturer, this is positioned carefully according to the instructions provided.

4. Set the electrosurgery unit to the minimum setting advised for this procedure by the manufacturer.

5. Swab the area to be treated with sterile saline; this is repeated throughout the procedure to allow maximum desiccation and to prevent superficial charring.

6. Place the ball electrode at the margin of the lesion and hold at 90°, just touching the skin. If pressure is exerted unnecessarily tissue damage may occur, and if skin contact is not maintained hyfrecation may take place, hindering penetration to deeper tissues (Fig 16.15).

7. Depress the foot or hand switch and release after approximately 2 seconds. A blanching of the tissues should occur. This indicates desiccation. If blanching has not occurred, reset to the next higher setting until blanching is seen. Blanching may take some seconds to emerge, so do not readjust the setting until you are sure of the result. Once the blanching has been achieved, the process is repeated around the lesion periphery, with each area of blanching interconnecting, until a complete outer ring of white tissue is formed. Continue the process in decreasing circles, overlapping each circle until the whole lesion is desiccated. This will have produced a blanched area or ‘white cap’ effect (Fig 16.16).

8. Use the blunt edge of a scalpel to work around the periphery of the blanched area to loosen it – desiccation will have caused separation at the dermoepidermal junction. Using a pressing and lifting motion, carefully remove all the desiccated tissue to reveal the underlying dermis (Fig 16.17).

9. Using a lower setting and a ball probe, perform haemostasis as required.

Figure 16.15 A 4-mm probe held in contact with plantar heloma durum prior to electrodesiccation.

Figure 16.16 After electrodesiccation is completed. Heloma durum showing the ‘white-cap’ effect.

Figure 16.17 Removal of desiccated tissue.

Perniosis (erythema pernio, chilblains)

Chilblains represent one of the conditions in which intervention to control the inflammatory process is necessary in order to prevent additional tissue damage. Theoretically, chilblains can be divided into four stages, but the initial stage, the cyanotic stage, often passes unnoticed. The hyperaemic stage is noticeable on examination and is symptomatic. This is followed by the congestive stage, after which the lesion may resolve or pass to the ulcerative or broken chilblain stage. In the hyperaemic stage the areas affected are variously described as being red, hot, burning, itchy or painful. At this stage the patient tends to scratch the area and cause a break in the skin. The application of cold compresses is essential to control the symptoms of this stage, and to reduce the volume of tissue fluid and blood in the area and diminish the possibility of broken chilblains. Cool evaporating dressings such as gauze dressings saturated with witch hazel are invaluable. At the congestive stage the principle of treatment is to stimulate the local circulation with rubefacients, vasodilator creams or the application of heat. Care must be taken that the peripheral circulation is adequate to cope with the effect of the application of any of the above. Any counterirritants or heat applied locally will cause an increase in cellular metabolism, with a resultant increase in waste products. Cells require an adequate blood supply to deliver oxygen to meet the increased demands of the cells and an adequate drainage system to remove the waste products. The action of a mild rubefacient with gentle massage to the area can be used to stimulate locally when the circulation is impaired, which is the case in many older patients. If appropriate, heat can be applied via the use of an infrared heat lamp, wax baths or a warm footbath. Numerous proprietary rubefacients and vasodilators are available.

In elderly patients the risk of tissue breakdown is increased. The most common site for broken chilblains is any area receiving excessive pressure or friction. The dorsum or apices of the digits are particularly at risk, as is the medial aspect of the first metatarsal joint in association with hallux abducto valgus, and the lateral aspect of a prominent fifth metatarsal head. The objective when this stage is reached is to encourage healing and prevent the entry and spread of infection. In the majority of cases the site is tender and the surrounding tissues cyanotic due to a generally impaired blood supply. Where the area has ulcerated in a younger healthy individual, due usually to trauma, the surrounding tissues exhibit the signs of an acute inflammation. Healing is achieved by removal of pressure from the area, which should include deflective padding and, if necessary, advice on footwear. Infection is prevented by the application of a topical antiseptic or interactive dressing. Patients who have circulatory or sensation impairment should be monitored very closely and, if deemed necessary, referred to their general practitioner for antibiotic therapy.

Patients who are subject to chilblains should be advised about preventive measures. These should not be limited to the foot but should include advice on keeping the legs warm with the use of trousers, and extra thick tights in ladies and the use of ‘long johns’ in men.

If prolonged exposure to cold is unavoidable, the feet should be warmed slowly. Warm-lined footwear and thick woollen socks (or two pairs of fine socks) should be worn, provided they are not constricting by tightening the shoes and causing further local areas of ischaemia.

Thermal insoles can be manufactured and inserted within the footwear to retain heat. If the footwear or hosiery becomes wet it should be changed as soon as possible, because damp cold appears to precipitate the formation of chilblains more readily than dry cold conditions. The circulation can be stimulated by means of rubbing in a cream or ointment specially formulated for the treatment of chilblains, many of which contain an antipruritic agent. Some studies have shown the use of systemic therapy such as nifedipine to be of advantage in the treatment of chilblains, and this may prove of benefit to the patient with severe chilling and the complications of ulceration. However, it should be used only if prescribed by a general medical practitioner.

Ulceration

The management of established ulceration is discussed fully in Chapter 10.

Hyperhidrosis

A hyperhidrotic skin loses its natural elasticity and cannot withstand tensile and shearing stresses, resulting in fissures and blisters. Furthermore, it is an ideal substrate for fungal and bacterial infections to become established and is a source of embarrassment to the patient.

In the management of hyperhidrosis it is important to appraise all footwear worn by the patient and also the demands of their occupation. Instances exist where a patient’s sensitivity to sweating and foot odour has led to them enclosing their feet in occlusive footwear when the reverse approach was indicated. Occupational factors are less easily controlled, but a willing approach by the patient can often improve the condition, in particular patient compliance with regard to the use of footwear (the avoidance of moisture-retaining materials) and hosiery (wool or cotton) that will absorb the sweat and prevent it lying on the skin. Various treatment strategies can be adopted for general hyperhidrosis of the feet depending on the severity of the condition. These can range from the application of dusting powders, to swabbing with an astringent lotion, to the administration of footbaths containing an astringent medicament. For general, more severe hyperhidrosis a small number of crystals of potassium permanganate dissolved in a footbath is an effective, cheap and easily obtained treatment. Care should be taken not to make the solution too strong or a brown discoloration of the skin will result, and it may even induce skin irritation (Martindale 1999). If the hyperhidrosis is severe, daily footbaths with tepid water, a few crystals (usually two or three, but no more than four) of potassium permanganate (enough to turn the water pale pink) for 15 minutes at a time over a period of a few weeks should result in a dramatic reduction in sweat symptoms. When maceration has ceased, the footbaths should be reduced to twice weekly. Footbaths containing 3% formalin may also be used, but care must be taken to avoid overuse due to the higher incidence of allergic reactions with this treatment (Martindale 1999). In less severe cases, contrast footbaths in conjunction with lotions and powders are effective.

Spirit-based astringent agents (e.g. 3% salicylic acid) may be applied interdigitally if there is excessive maceration, and the application of dusting powders is advantageous, particularly those that contain an antifungal agent. Cases of salicylate poisoning have been reported following excessive application of salicylic acid compounds, and long-term application of these substances on the skin should be avoided (Martindale 1999). Interdigital fissuring should be treated rigorously with astringent antiseptics. There are many astringent, antiseptic and antifungal agents available commercially, including insoles that are absorbent and deodorising. The patient should be advised to dispense with shoes and socks whenever possible, or to wear sandals, to pay particular attention to foot hygiene, to change hosiery daily and to alternate footwear.

This condition is rarely a short-term problem, and it cannot be permanently cured by any of the above treatments. However, patient compliance with management is easily achieved in this condition because of the discomfort. If the excessive sweating is not isolated to the foot but is more generalised, help should be sought from a medical practitioner. It may be that the condition cannot be treated, but underlying factors such as stress and diet may be controlled.

Anhidrosis

Many instances of anhidrosis result from poor peripheral blood supply in the elderly or in diabetic patients with autonomic neuropathy. Where this is the cause, little more can be done than to apply emollients regularly, preferably daily after washing. The choice of emollient matters little, as the purpose is to prevent moisture loss from the skin. Hydrous lanolin, E45 cream, white soft paraffin, urea-based preparations or proprietary medicaments incorporating lanolin are suitable. It is useful to remember that long-term use of lanolin can cause skin sensitisation reactions (Martindale 1999).

The main complication of anhidrosis is the formation of fissures due to the reduction of epidermal elasticity and applied tensile stress. These can become a considerable problem, causing much pain and disability, as well as being a site for the entry of infection. Fissuring is most commonly found on the borders of the heel, and is associated with callus formation.

Treatment consists of careful reduction of the callus at the edges of the fissures, and treatment with an antiseptic cream and an occlusive dressing for a few days. If the anhidrosis is severe, and is associated with thickening of the stratum corneum, a thick layer of emollient occluded and left in situ overnight is a suitable treatment. If fissures are open and infected, antiseptic emollient dressings are indicated until the lesion heals, followed by the regular application of emollients.

Tinea pedis

Tinea pedis is most commonly found in adults, being relatively uncommon in children. The common causative organisms in the UK, in order of frequency, are: Trichophyton rubrum, Trichophyton interdigitale, Epidermophyton floccosum, Microsporum canis (cat and dog ringworm), Trichophyton verrucosum and Trichophyton mentagrophytes. Less frequently the following may be isolated: Trichophyton tonsurans, Trichophyton erinacei and Microsporum gypseum. Scopulariopsis brevicaulis can cause onychomycosis in nails that are already affected by a pathological process such as onychauxis or onychogryphosis, and is most commonly found in the first toenail. Other fungi that can be isolated from dystrophic nails are Aspergillus, Fusarium and Pyrenochaeta species. Candida albicans can affect skin and nail, particularly at the base of the nail plate under the eponychium, where it is very difficult to eradicate due to its inaccessibility. Interdigitally, Candida infections are frequently secondary to dermatophyte infections with associated fissuring. A severe Candida infection – chronic mucocutaneous candidosis – is a relatively uncommon chronic condition that presents in childhood and affects the mouth, skin and nail. In the foot it is associated with hyperkeratotic areas and dystrophic nails.

The only positive means by which the infecting organism can be identified is by laboratory diagnosis. Superficial mycoses will be identified by direct microscopy and culture. In skin mycosis the skin scrapings should be taken from the active margin of the skin affected, and if vesicles are present the active fungal cells will be contained in the roof of the blister, which should be removed completely for analysis. Prior to removal of scrapings for mycological examination the skin should be swabbed with alcohol to remove any medication that may have been applied. Scrapings from nails should be from the under surface and as far proximally as possible. Fungi in the distal portion of the nail may not be viable if the infection is active proximally, and scrapings taken from that area frequently produce negative results on culture.

Infection of the host by the fungi is due to penetration of keratinised cells. Fungi are able to enter the keratinised cells by producing enzymes that can degrade or split the keratin, and the fungal hyphae are then able to penetrate between the keratinocytes. Consideration of the epidemiological factors involved in dermatophyte infections is relevant when considering the treatment of tinea pedis. The incidence rises in winter with the wearing of occlusive footwear. The main areas where conditions are suitable for transmission of infection are swimming pools, communal changing areas such as sports halls and schools, industrial shower rooms used by employees after work (e.g. miners or servicemen), or any area where there are liable to be infected skin squames on floors. Dermatophytes can survive for months if not years in desquamated skin cells. If the infection is zoophilic and the infected human has a cat or dog, the infected material is likely to be from the home and the spread can occur directly from the pet or from chairs, floors or floor coverings. An atypical mycosis may have been acquired by a patient who has travelled abroad, particularly outside Europe. This should always be taken into account if an unusual clinical picture is seen.

General issues regarding treatment should be to identify the probable source, if possible, and to provide advice on avoidance, foot hygiene and type of footwear. Advice should be given to eliminate barefoot contact with all surfaces that are liable to be contaminated. Personal foot hygiene should be of the highest standard, the feet should be meticulously dried, and the shared use of towels or footwear should be avoided. The type of footwear worn by the patient should be considered and, if occlusive footwear cannot be entirely avoided because of his or her occupation, the wearing of open sandals should be advised whenever possible to allow free circulation of air. Hosiery should be changed daily, and shoes should be regarded as a potential source of reinfection and treated with a fumigating agent (e.g. 10% formalin solution). If formalin is used, care must be taken to aerate the shoes prior to use to avoid irritation caused by the agent. Disinfection of shoes is easily achieved by placing formalin in a shallow container, such as a tin lid, inside the shoe, placing the shoes inside a plastic bag and leaving for 24 hours. Provided the ambient temperature is about 15°C, the inside of the shoe will be exposed to a high concentration of formalin. The shoes should be exposed to the air for some hours after such treatment to minimise the risk of hypersensitivity reactions (Martindale 1999).

Tinea unguium (onychomycosis)

Candidosis

Candida infections can affect both skin and nail (see Chs 2 and 3). The most common sites in the foot to be affected are the interdigital spaces and the nail. In appearance the web spaces are extremely macerated with open fissures, and have a distinctive yeasty odour. The infection may be secondary to a dermatophyte infection, but in contrast to the dermatophyte infections it is unlikely to spread. Paronychia as a result of a Candida infection is usually chronic in nature and is caused by C. albicans or C. parapsilosis. The nail folds and surrounding tissues are grossly inflamed and painful. The affected border of the nail will exhibit onycholysis and there will be a discharge of pus. Staphylococcal and Gram-negative infections may coexist; therefore, bacteriological identification should also be sought. The nail plate itself may become infected in association with paronychia. The nail plate will not become thickened, but onycholysis and destruction of the distal end of the nail plate may result. This condition is more common when Raynaud’s disease, chronic chilblains or Cushing’s syndrome are present. It is unusual to find associated skin symptoms elsewhere on the foot.

Most of the superficial Candida infections respond to topical applications of the azoles, terbinafine or Nystatin. For paronychia the treatment should be in solution form to enable it to run into the nail folds, and treatment should be continued for 3–4 months. Oral therapy with terbinafine, itraconazole or ketoconazole is necessary when the nail plate is involved.

Heat and cold

Heat and cold have been used as a method for the treatment of trauma since 400 BC. The local physiological effects of heat and cold help many of the adverse local pathological changes that occur as a result of the tissue damage. Subsequently, the cardinal signs and symptoms of inflammation (rubor, calor, dolor and tumour) may be reduced, healing assisted and rehabilitation time improved.

Heat

Heat may be applied to the skin by:

Ultrasound

Sound is mechanical vibration to which the human ear responds in the range 20 000–30 000 Hz. Unlike other forms of mechanical energy, sound cannot travel through a vacuum. It can only be transmitted through media such as solids, liquids or gases.

The mechanical vibrations set up a waveform motion which, when passing through a medium, causes alternate compression and distension of its particles. Only the form of the waves moves forward, while the particles through which they pass merely move back and forth around a mean point. The progression of a sound wave through a medium depends on the transfer of energy from one particle to the next.

Ultrasound is defined as inaudible, acoustic, mechanical vibrations of high frequency (usually 1–3 MHz) that produce thermal and non-thermal physiological effects (Gann 1991). Ultrasound is generated by a transducer, a device that transforms one form of energy into another. The most commonly used transducer in ultrasound is crystal quartz, which changes electrical energy into mechanical energy using the piezoelectric effect. The voltage across the ultrasound transducer may be applied continuously over the entire treatment time (continuous mode) or in short bursts (pulsed mode). The energy in an ultrasound wave is characterised by intensity. This is the energy crossing a unit area perpendicular to the wave in unit time. The units used in medical ultrasound are watts per square centimetre (W/cm²).

The energy of the longitudinal wave will produce the mechanical effects of compression and rarefaction in the tissues through which it passes.

Thermal effects. When ultrasound travels through tissues a percentage of it is absorbed, leading to the generation of heat within the tissues. As the waves pass through the different tissues or media of the body (skin, muscle, tendon, etc.) they are subject to varying refractions and scatter. As a result, the intensity of an ultrasound beam decreases as it penetrates deeper into the tissues – the ‘half-value distance’. The half-value depth for soft, irregular connective tissue is approximately 4 mm at 3 MHz but about 11 mm at 1 MHz. The amount of absorption will depend on the nature of the tissue, the vascularity of the area and the frequency of the ultrasound. Tissues with a high protein content absorb ultrasound more easily than do those with a high fat content.

The higher the frequency the greater the absorption (Young & Dyson 1990). Structures heated preferentially are periosteum, superficial cortical bone, joint menisci, fibrotic muscle, tendon sheaths and major nerve roots. It is important that the clinician has a good knowledge of the structures that lie between the ultrasound equipment head, the injured tissues and the deeper tissues. Because of the application of the ultrasound there will be an increase in tissue temperature, increased vasodilatation, and increased cell metabolism, with a resultant decrease in joint stiffness and pain relief.

Non-thermal effects/physical properties. There are situations in which ultrasound produces physical effects on biological tissues but without a significant increase in temperature. Such situations would include bone repair, stimulation of tissue regeneration and soft-tissue repair (Dyson & Pond 1970). The mechanisms involved in the physical or non-thermal effects are the result of cavitation, acoustic streaming or standing waves.

• Cavitation. Ultrasound can cause the formation of microsized bubbles or cavities in gas-containing fluids (Ayme & Carstensen 1989). These bubbles can be either useful or dangerous. Cavitation may be unstable and collapse of the bubbles will occur, resulting in an excessive rise in local temperature. This can best be avoided by continually moving the treatment head and by using intensities below 3 W/cm². Stable cavitation is not dangerous and can have beneficial effects. As a result of cavitation there is localised, unidirectional, small fluid movement around the vibrating bubble. This small fluid movement around cells (microstreaming) is believed to play a role in the therapeutic effect of ultrasound (Dyson & Pond 1970). Modifying the ultrasound beam results in microstreaming whereby the permeability of the cell membrane and the direction of movement of molecules into cells is influenced.

• Acoustic streaming. This describes the unidirectional movement of a fluid in an ultrasound field. Acoustic streaming can accelerate tissue repair as a result of increased capillary permeability, stimulation of activity of mast cells and fibroblasts, and the increased production of growth factors by macrophages (Maxwell 1992).

• Standing waves. When an ultrasound wave encounters the interface between tissues with different acoustic abilities (e.g. bone and muscle) reflection of a percentage of the wave will occur. The reflected wave can interact with oncoming waves to form a standing wave field in which the peaks of intensity of the waves are stationary and are separated by half a wavelength. This causes gas bubbles to collect and cause damage to endothelial cells and tissue in the immediate area. This can be avoided by moving the head of the transducer continuously throughout the treatment.

Method of application. Ultrasound can be applied either directly or indirectly to the area being treated (Robertson & Ward 1996).

Direct application is achieved by placing the treatment head in contact with the skin via a coupling gel recommended by the manufacturer of the equipment. The treatment regimen is selected and the machine switched on. It is essential to maintain continuous contact between the whole of the treatment face and the skin to avoid damage to the quartz crystal in the transducer. While maintaining an even pressure, the treatment head is moved in a circular or figure-of-eight motion over the surface.

Indirect application is achieved by immersing the area to be treated in a water bath. The water acts as the conductor between the tissue and the transducer. This method is particularly useful for irregular surfaces such as the dorsal aspect of the foot and the first metatarsophalangeal joint. The foot should be placed in a non-metallic basin containing water, preferably distilled water to avoid air bubbles but this is not essential. The dosage is selected and the treatment head is moved continually and parallel to the part in a circular motion about a inch (about 6 mm) from the skin.

Ultrasound therapy can also be used in conjunction with topical non-steroidal anti-inflammatory preparations. This method is considered to improve the management of a variety of musculoskeletal conditions and acute sports injuries. It is thought that ultrasound may enhance the penetration of some drugs across the skin by the process of phonophoresis (Benson & McElnay 1994).

Suggested treatment dosages in podiatry. These are as follows:

• Intensity:

low (0.25–0.5 W/cm2) for recent and acute conditions

medium (0.8–1.0 W/cm²) for chronic conditions.

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• Frequency:

high frequencies are absorbed more rapidly and therefore are more suitable for superficial tissues

low frequencies penetrate deeper.

• Time:

start with a short time (e.g. 3 minutes); this can be increased in subsequent applications.

• Pulsed/continuous mode:

continuous – thermal effect (chronic conditions)

pulsed – non-thermal effects (acute conditions).

Indications. Ultrasound can be beneficial in the treatment of soft-tissue injuries, inflammatory conditions such as painful hallux limitus, and rheumatic and arthritic conditions.

Contraindications. The use of ultrasound is contraindicated when infection is present in the area, as there is danger of the infection spreading. Ultrasound should never be used if there is a history of deep venous thrombosis, as there may be a risk of embolism. As with other forms of heat therapy, ultrasound is contraindicated in peripheral vascular disease. Other contraindications include the presence of tumours or tuberculosis, or if the patient has recently received radiotherapy, has haemophilia or if there is a suspected fracture. Ultrasound should never be used over the epiphyseal plate in a growing child as it may affect the growth of the limb (Oakley 1987).

CASE STUDY 16.4 MANAGEMENT OF PLANTAR FASCIITIS

A 55-year-old woman was referred by her general practitioner (GP) complaining of pain on weight bearing in the region of the right heel which increased on walking. The pain radiated along the medial longitudinal arch in the foot.

The patient was overweight, worked full time in a local supermarket and her normal footwear was a court shoe with a 2-inch heel. Jack’s test, whereby the hallux is dorsiflexed putting maximum tension through the plantar fascia and the medial attachment of the facia to the calcaneum, elicited the characteristic diagnostic pain of plantar fasciitis. Examination also revealed limited ankle dorsiflexion (less than 10°) and excessive subtalar joint pronation.

Her GP had prescribed Ibuprofen 400 mg, which had reduced the initial acute symptoms. She had no other medical problems, and the vascular and neurological status was normal on assessment. The patient was advised on appropriate footwear and a course of ultrasound therapy was administered twice weekly. Following the first ultrasound treatment the patient had a bow strapping applied to the foot and a Slimflex insole inserted into the footwear. The patient was shown stretching exercises for the plantar fascia and Achilles tendon. The patient was referred to the dietician for advice on an appropriate diet.

The patient complied with the footwear advice and stretching exercises. Subsequently, a casted orthosis, comprising an ethyl vinyl acetate (EVA) shell with a meniscus in deflective material at the heel, was manufactured, and this limited the subtalar joint pronation; The patient’s symptoms subsided after a period of 4 weeks. Her weight gradually decreased, and after 4 months she was pain free.

Cold

Cold has the converse effect of heat. The topical application of cold has an effect on the sympathetic adrenergic nerve fibres, causing constriction of the arterioles and venules and resulting in vasoconstriction. Cold will reduce the metabolic rate of tissues and there will be a lowered demand for oxygen and nutrients. Cold will also reduce the effect of the chemical mediators of inflammation, minimising the inflammatory process. Therefore, there will be a decrease in vascular permeability, an increase in the viscosity of blood, a reduction in the leakage of exudate from the vessels and consequently a reduction in the amount of swelling (Lehmann & DeLateur 1990).

Cold is useful in the initial treatment of acute trauma such as sprains, as it will limit the initial inflammatory response and thus limit tissue swelling and pain. However, the use of cold therapy should be avoided in patients who are elderly, have peripheral vascular disease, Raynaud’s disease and sensitivity to cold, peripheral neuropathy or cardiovascular disease.

Methods of application

Properties of laser light

A combination of properties makes laser light unique, allowing the treatment of specific conditions. The beam from a single probe has a narrow bandwidth (usually 660–950 nm), and the photons are in-phase, with very little divergence. Each photon carries the same amount of energy, resulting in the light being consistent and uniform.

Some of the important features of laser light are listed below and in Figure 16.18.

Figure 16.18 Some of the important features of laser light.

Prior to use of any course of laser therapy, the wavelength, pulse frequency and energy must be considered.

The power is the strength or power output of the laser. The power density is the light-output power per unit area of the target, and is measured in watts per centimetre squared (W/cm²). It can be calculated using the following formula:

The energy density is the total amount of energy conducted into the tissues, measured in joules per centimetre squared (J/cm²).

The pulse frequency is the number of pulses per second. When a laser is pulsed, the laser light power varies between the peak output of the pulse and zero.

The wavelength has a biological effect; it is therefore important to use the correct wavelength for the right indications (Baxter 1994).

The effect of laser light

Treatment with laser therapy produces biochemical and photobiological effects within the cells and tissues. Together, these stimulatory effects are known as biomodulation (Turner & Hode 2002). Local metabolic changes occur, such as increased inflammatory response, effects on the immune system and increased formation of capillaries, as well as a number of other effects that are of therapeutic value.

The radiation emitted by a laser is athermic. However, the biomodulation effects have been shown to be dose-dependent. The laser dose is calculated as:

Safety

As with any other electrical equipment, the laser machine must be checked and serviced regularly. Local rules should be drawn up that detail the safe use of the unit.

Only authorised users who have undergone approved training should provide laser treatment. The treatment should be given in a confined area with no uncovered windows or shiny surfaces or mirrors in order to prevent reflection of the light. A warning sign should be mounted outside the area of treatment and should be clearly visible. Both the patient and practitioner must wear goggles designed specifically to filter the wavelengths emitted by the laser machine and to protect against damage to the eyes.

The laser machine must be switched off when unsupervised and not in use, and it must be calibrated regularly.

Treatment technique

It is important that the practitioner has a good knowledge of anatomy to ensure that the correct area is treated. The painful area should be pinpointed each time and the target area should be in its optimum position to receive treatment.

The patient should be advised of a possible flare up after the treatment (described later). To be able to monitor the treatment effects effectively, it is advisable to use adequate outcome measures.

The laser probe should be held at 90° to the skin. An appropriate technique, such as holding the probe still in one area or moving it over the skin, should be used depending on the area being treated. The probe should be in contact with the skin; the distance between the probe and treatment area should be minimal in order to prevent divergence of the beam and, therefore, ineffective treatment. Light reaching tissues from a distance (not in contact) aims over a larger area and is more superficial. Close-contact light penetrates deeper and over a localised area. This is demonstrated in Figure 16.19.

Figure 16.19 (A) Light reaching tissues from a probe not in contact with the skin aims over a larger area and is more superficial in its effect. (B) With the probe in close contact with the skin the light penetrates deeper and over a more localised area.

The light distribution in the tissues depends on the wavelength, with shorter wavelengths producing small rounded distribution and longer ones having an elongated ball effect (Turner & Hode 2002).

To prevent cross-infection the end of the probe should be wiped and any thin clear film can be used as a barrier. For the treatment of ulcerated lesions the clear inside sterile packing of wound dressings is useful for this purpose.

Contraindications

Magnetopulse is contraindicated in pregnant women and in those with tuberculosis or a viral illness. It should not be used (i) in juvenile diabetes, (ii) if there is a history of thrombosis, (iii) if the patient is susceptible to haemorrhage, or (iv) if the patient has a pacemaker.

When using magnetopulse the clinician must take certain precautions: remove all watches and ensure that the machine is kept away from all other electronic equipment such as computers.

Operation of magnetopulse equipment

There are 19 magnetic field intensity settings and 19 modulation frequency settings.

Start. Pressing a single momentary-action button, marked ‘start’, provides the signal to the applicator coils and starts an adjustable countdown timer. When high frequencies are selected, it may not be possible to notice the usual pulsation.

At the end of the selected time the system will automatically stop and an audible tone will sound, indicating the end of the treatment.

Stop. Pressing a single momentary-action button, marked ‘stop’, ends the treatment before completion of the set time.

The treatment regimen is flexible in increments of 1 minute, from 0 to 90 minutes, and the output is 120 VA/50 Hz. Magnetopulse machines can be obtained with either two or four treatment pads; the method of application will therefore vary.

Indications

Magnetopulse can be used in the management of the following conditions often encountered in podiatric practice: osteoarthritis, rheumatoid arthritis, ankle sprains, haematoma and bruising, bursitis, tendinitis. Suggested treatment regimens are given in Table 16.2, and examples of use are given in Tables 16.3 and 16.4.

Table 16.2 Suggested magnetopulse treatment regimens

Stage 1	Stage 2	Stage 3
Use this stage for acute cases. Treat once a day for 3 days and then every second day. When the condition improves, gradually increase the intensity, and then move to stage 2	Use for subacute conditions	Use for chronic conditions

Table 16.3 Osteoarthritis: suggested magnetopulse treatment regimen

Table 16.4 Ankle sprain: suggested magnetopulse treatment regimen

Faradism – muscle stimulation

Faradism involves the use of a low-frequency current (50–100 Hz). It is a faradic-type interrupted direct current with a pulse rate of 0.1–1 ms. This would produce a tetanic muscle contraction, which would be very uncomfortable, so the current is surged to produce alternate contraction and relaxation of the muscles similar to the normal contraction of muscles that have a normal nerve supply.

It is used to facilitate muscle contraction when the patient finds it difficult to produce effective muscle action. This may be because of inhibition due to pain after injury, postoperatively or arthritis. It may be used to re-educate a muscle action. This could be after prolonged disuse, as in flat foot, or incorrect use, as in abductor hallucis in hallux abducto valgus. It is also used to stretch and loosen adhesions and to improve venous and lymphatic drainage.

Large multifunction machines can produce faradism, but the most useful are small, portable, battery-operated machines with automatic surging.

Technique

2. To stimulate the intrinsic muscles, a footbath with inch (13 mm) of water is used. One electrode is placed under the heel and the other under the metatarsal heads. The patient is instructed in the same way. To stimulate the abductor hallucis using the bath, one electrode is placed under the medial side of the heel and a button electrode is used on the motor point of abductor hallucis.

Interferential

Two medium-frequency alternating currents of different frequencies from 400 Hz to 4250 Hz are applied to the body. Where the currents cross they ‘interfere’ with one other and set up a beat frequency. This is a low-frequency current. The two currents can be varied between 0 and 250 Hz to produce different physiological effects.

Tension strappings

Figure-of-eight strapping for the foot and ankle is shown in Figure 16.19. This strapping may be used for various conditions:

Figure 16.20 Figure-of-eight strapping for the foot and ankle. (A) Valgus or ‘D-pad. (B) Non-stretch strapping applied first to invert the heel. (C) Figure-of-eight elastic strapping. (D) Second application of non-stretch reinforcing strapping.

Depending on the structures that need to be supported or rested, the strapping can be applied in order to invert the foot and to support the structures on the medial aspect of the foot and ankle. Medial support is required, with or without the addition of valgus padding or D-pads, in cases of sprain of the deltoid ligament, acute or chronic foot strain and plantar fasciitis. Conversely, it may be applied in such a way as to support the structures on the lateral side of the foot and ankle. Lateral support is required, with or without a tarsal platform or ‘filler pad’, in cases of sprain of the external lateral ligaments of the ankle, and in some cases of pes cavus with associated postural instability. It may also be applied to hold the foot in a neutral position and to reduce tensile stress on the plantar aspect of the foot, and limit the motions in all directions. This is indicated in arthritis of the tarsal region.

The strapping of choice is a 5 cm (2 inches) or 6.25 cm ( inches) elastic adhesive bandage. This is preferred to non-stretch strapping, particularly where oedema is present, as it is less constricting. If hyperhidrosis is present or the patient is allergic to this material it may be applied over a soft cotton bandage. In order to prevent the plaster sticking to hair on the dorsum of the foot, cotton wool can be dragged across the sticky surface of the strapping to that area only. There will be some stretch of the material during walking but, if necessary, this can be minimised by the addition of two pieces of non-stretch strapping to reinforce and prolong the support given. Of necessity, these strappings are for short-term use only, and should not be reapplied if the skin becomes extremely macerated or signs of allergic dermatitis appear. If reapplication of adhesive plaster is contraindicated but support or limitation of movement is still required, the same strapping may be applied utilising crepe bandage. This will reduce the support that can be achieved and it is also a bulkier form of strapping, which may cause constriction in the footwear, but is a valuable alternative.

Medial support

The strapping should just avoid the anterior margin of the plantar fatty pad, leaving it free to change shape on weight bearing, otherwise the edge of the strapping cutting across the fatty pad will cause discomfort.

Depending on the degree of support or correction required, valgus padding may be incorporated into this dressing, with it being applied to the foot before the strapping is in place, or alternatively it may be inserted into the shoe. Firm supporting footwear must be worn at all times with this strapping, the unshod foot never being allowed to bear weight. This strapping will give support for up to 10 days before requiring renewal.

Lateral support

The technique is similar to the strapping for medial support but the strapping is applied in the reverse direction, the upward tension being exerted on the lateral side of the foot, which is held in eversion. No preliminary reinforcing strap is necessary to evert the foot, but the final reinforcing strap should be applied as previously described, but in the reverse direction. Additional lateral support can be provided if necessary by fitting a tarsal platform into the shoe.

Neutral support

The object of this strapping is to restrain painful movement in the tarsal joints. The most comfortable position of the foot should first be established by passive manipulation. No preliminary reinforcing strap is necessary. The flexible bandage is applied as for medial support but without the medial tension. The final reinforcing strap is applied with approximately equal tension on the medial and lateral borders of the foot before being secured to the leg above the ankle. Additional mediolateral support can be provided, if required, by fitting a combined tarsal platform and valgus pad into the shoe – the ‘tarsal cradle’.

Care must be taken when applying any restricting strapping to the foot when oedema is present or gravitational swelling occurs towards the end of the day. Advice should be given regarding elevation of the limb, but if the swelling is severe enough to cause discomfort or restrict the circulation to the digits the patient should be advised to cut through the strapping on the dorsal aspect up to the level of the base of the metatarsals. This will relieve some of the pressure, while the strapping will continue to give some support to the foot and ankle. If this is insufficient, the strapping must be removed or reapplied in the form of a crepe bandage, which can be removed by the patient and reapplied the following morning.

Orthotic techniques appropriate as follow-up to ‘figure-of-eight’ foot and ankle strappings may be any of the following: elastic anklets, corrective or palliative orthoses incorporating valgus, tarsal platform or combined tarsal cradle support, buttressed heels and wedged heels. Unlike the strapping, however, all such devices provide only passive support or correction.

Valgus padding

Valgus padding, so-called because it is used in cases of valgus foot, has two separate but related elements, a plantar cushion and a medial flange. The plantar cushion fills the concavity of the longitudinal arch, with the object of affording support to the joints and the muscular and ligamentous attachments, which become strained in abnormal pronation. It is essentially palliative in function.

The medial flange extends towards, and if necessary over, the prominences of the sustentaculum tali and the tuberosity of the navicular. Its function is to encourage some degree of inversion of the foot and thereby some correction of abnormal pronation. This is achieved by the pressure of the padding against the firm counter of the shoe. Where such correction is possible, it should be initiated primarily by means of medial heel wedging, but the medial flange is often necessary to supplement the correction.

It follows, therefore, that the design of valgus padding must be varied considerably to meet individual needs. When applied directly to the foot it is constructed of a compressed felt material in either 5 mm or 7 mm thickness.

Tarsal platform (filler pad)

The tarsal platform or ‘filler pad’ (Fig. 16.21) is never applied to the foot except as a short-term measure. It is mainly used as a component of orthoses or as an insert in footwear. Its main function is to bring the lateral border of a highly arched foot into firm contact with the waist of the shoe. By raising the floor level to the foot, it enlarges the weight-bearing area and to that extent relieves the loading on the heel and the metatarsal heads. It also tends to evert the foot and is useful where there is peroneal strain.

Figure 16.21 Tarsal platform (filler pad) and extended to tarsal cradle. (A) Tarsal platform on leatherboard insole. (B) Tarsal cradle (combination of platform and valgus or ‘D-pad).

The basic design is that of a platform of firm material extending the full width of the insole from the anterior margin of the heel seat to just behind the tread (Fig. 16.21A). It fills the empty space between the lateral border of a highly arched foot and the waist of the shoe. There is no contact between it and the plantar aspect of the medial longitudinal arch, the bulk of the padding on the medial side serving only to anchor it more firmly to the waist of the shoe. It is the limitation of contact to the lateral border only that tends to evert the foot, thus stabilising the ankle in cases of abnormal inversion. The medial portion of the padding also provides the base for additional valgus padding where this is needed to form a tarsal cradle.

When required, the anterior edge of the platform may be thickened to form a metatarsal bar, or may be extended under the three middle metatarsal heads to form a ‘double-winged’ metatarsal pad to protect the first and fifth metatarsal heads, or extended as shafts under the first and fifth to protect the middle three, or extended as a shaft under the first alone in hallux rigidus.

Padding and strapping for hallux abducto valgus

The padding and strapping selected for this condition depends on the cause of the condition, and the mobility and age of the patient. The cause should always be considered, and the structure, shape and application of the padding related to the cause. It is beneficial to use adhesive padding as a temporary measure prior to the manufacture of orthoses, and the size and shape of the footwear must be given full consideration for the short- and long-term management of the condition. Strapping may be used on a younger patient with incipient hallux abducto valgus in order to lessen the deviation of the hallux and thereby relieve strain on the periarticular tissues and protect the medial eminence from shoe pressure. In an established case of hallux abducto valgus where correction is impossible, podiatric management consists of protection of the medial eminence by means of a felt crescent or oval cavity pad. The efficacy of this form of deflective padding depends on the degree of deformity present. If the degree of deformity is great, then footwear modifications in the form of balloon patches are essential to relieve pressure on the area. Often it is not the medial eminence that is the cause of discomfort but the resultant areas of overloading on the plantar aspect of the foot and the pressure on toe deformities. The most common site of corn/callus on the plantar aspect is on the second, third and fourth metatarsal heads or any combination of the same. This is due to an incompetent first metatarsal and toe deformities. The padding/orthosis applied should relate to the cause of the overloading. In this instance a short shaft to the first metatarsal combined with a metatarsal bar should increase the loading through the first metatarsal head and realign the lesser toes, if sufficient movement is available.

In a younger patient, where there is still mobility in the joint and passive movement can return the angulation to near normal, it is imperative that a biomechanical assessment be carried out to ascertain whether an underlying malalignment, such as forefoot varus, may be responsible for abnormal foot function and the development of the hallux abducto valgus. In this instance, although strapping may be used, as suggested above, it is imperative that a functional orthosis is in situ as soon as possible to prevent further deformity from occurring. This management strategy should include the use of an exercise regimen, night splints if appropriate, correction of any lesser toe deformities associated with the condition (see silicone devices) and precise footwear advice pertinent to the individual patient. Silicone devices in the form of an orthodigital splint embracing the middle three toes and an interdigital wedge for the first cleft eliminates any possibility of the lesser digits being abducted by the wedge, as they are firmly fixed against the sole of the shoe by the superimposed weight. For this reason, the interdigital wedge in this form also exerts better control on the hallux to prevent further lateral deviation.

The strapping of choice is adhesive stockinette, or similar, which has one-way stretch only. This is cut into a flask or butterfly shape and the anterior ends are first adhered to the hallux and secured there by a narrow strapping. The non-stretch dimension of this material must lie anteroposteriorly. The main part of the stockinette is then drawn back over the joint with sufficient tension to correct the line of the hallux to the extent required. The ‘wings’ are then stretched laterally across the dorsal and plantar surfaces of the metatarsal and adhered, covering any padding that has been applied to the joint (Fig 16.22).

Figure 16.22 Flask strapping to realign hallux abductus. The strapping is adhered around the hallux, below the interphalangeal joint; the hallux is passively moved from its abducted position, and the strapping is then applied with sufficient tension over the prominence and the medial side of the foot before being stretched laterally.

Padding and strapping for hallux limitus/rigidus

The acute form of hallux rigidus is occasionally seen in the younger age group, often associated with a sports injury or repeated minor trauma due to a biomechanical dysfunction, but it is relatively uncommon. It is an extremely painful condition and is associated with inflammation and muscle spasm, traumatic synovitis and subsequent capsular contraction, mainly on the plantar surface. Untreated cases, or where there is repeated minor trauma, may display some marginal dorsal osseous lipping and may progress to chronic hallux limitus/rigidus. This often depends on the effectiveness of the treatment at the acute stage, as well as on the cause. The clinical features are a rapid onset associated with pain and stiffness in the first metatarsophalangeal joint. The patient has great difficulty in weight bearing on the area and walks with the foot in a supinated position. Although the joint has inflammatory changes these are not always obvious superficially. The great toe is frequently held in a plantar-flexed position due to muscle spasm.

The treatment of acute hallux rigidus consists of an appropriate physical therapy to reduce the inflammation and pain in the joint and rest. If acutely inflamed, the patient may find contrast footbaths more beneficial prior to the application of heat. In severe cases rest will consist of total non-weight bearing and may require a plaster cast, although this is a rare occurrence. On occasion, hydrocortisone injections into the joint may be required. Normally, padding or strapping to reduce movement and relieve pressure on the first metatarsophalangeal joint on weight bearing is sufficient. A single-wing metatarsal pad is often the most readily tolerated padding, as it relieves the load on the painful joint, facilitates the inverted position of the foot that is adopted in such cases, and thus helps to minimise dorsiflexion at the joint. As soon as the pain and muscle spasm have been relieved, discontinue the padding and strapping but continue the heat therapy and restore normal movement in the joint by gentle traction and circumduction exercises. It is essential with acute hallux rigidus that the predisposing cause is identified and treated to prevent long-term problems with the joint function.

Chronic hallux limitus/rigidus is a slowly progressive disorder and, although it may halt at any stage, it may not become completely fixed. It may or may not be associated with pain in varying degrees. The loss or limitation of movement in the first metatarsal phalangeal joint may be associated with pain, especially after walking a distance; however, the pain may be due only to the associated lesions. The symptoms of pain will be exacerbated by wearing a higher heeled shoe. Because of the lack of movement at the metatarsophalangeal joint this detracts from the fulcrum action of the great toe. Pain in the first metatarsophalangeal joint may cause the patient to walk on the outer border of the foot and utilise the interphalangeal joint at the propulsive phase of gait when weight is transferred to the medial side of the foot. Secondary problems that may occur in the longer term area:

These secondary problems must be addressed with appropriate padding and footwear advice.

Pain at the first metatarsophalangeal joint that is produced on movement can be alleviated by limiting the movement at the joint. This can be achieved by means of a long shaft pad applied with rigid fan strapping. If there is insufficient room within the shoe then the fan strapping may be applied alone. This strapping utilises rigid adhesive strapping of 2.5 cm (1 inch) width (Fig. 16.23). With the first metatarsophalangeal joint held in the neutral position, the strapping is applied from a point just proximal to the interphalangeal joint of the great toe to the base of the first metatarsal. There are five pieces of strapping, which are applied in the following order: the plantar, dorsal and medial aspects of the first ray; and the final two pieces of strapping fill in the spaces between the previous three straps. This is an extremely effective method of limiting the movement in the joint. The strapping is adhered at the distal and proximal margins, as illustrated in Figure 16.22. Patients obtain great relief from padding and strapping, but at the earliest opportunity long-term orthoses should be prescribed, taking into account the biomechanical abnormality that has led to the pathological changes in the joint. When strapping is contraindicated, the joint can be immobilised by the temporary use of a leatherboard template with a shaft adhered to its undersurface made from either a thin rigid polythene material or other rigid material. The above measures will be ineffective unless advice on appropriate footwear is given and adhered to by the patient. There must be sufficient length and depth to the shoes to prevent any impaction of the proximal phalanx on the metatarsal head or pressure on an enlarged joint. The heel height should not be higher than 3 cm, and there should be a retaining medium to prevent forward movement and stubbing of the great toe. The sole should be rigid with an adequate toe spring to assist function in the propulsive phase of the gait cycle. If there is abnormal excessive pronation, the counter of the shoe should be stiff and a patient-specific orthotic may be prescribed to prevent the pronation occurring. Adaptations to footwear, if required, consist of a rocker bar added to the outer sole of the shoe to enable the foot to ‘rock’ over the fixed joint. A steel stiffener may be inserted between the outer and middle sole to reduce movement and pain in a joint where complete fixation has not yet occurred. These measures can be carried out by a competent shoe repairer or cobbler. Patients who are in occupations that enable them to choose any type of footwear frequently find that clogs are extremely comfortable, and if pain is a factor it is remarkably reduced with this type of footwear. Other measures that may be adopted are stretching or balloon patching to accommodate any joint enlargement, exostosis or bursa formation (see Ch. 17).

Figure 16.23 Fan strapping for hallux limitus. May be used alone, as illustrated, or used in conjunction with a shaft pad (see Fig. 16.7).

Plantar digital neuritis

This condition can present with or without any obvious structural abnormality and this can make the selection of padding and strapping uncertain. It should be explained to the patient that several forms of padding may alleviate the pain, and when the most appropriate padding has been determined a long-term orthotic device will be fitted. A plantar metatarsal pad with a U to the painful area is most often effective when applied with a full metatarsal strapping. Alternatively, a short-shaft pad, 2–4 plantar metatarsal pad or a metatarsal bar may be the padding of choice. All are commonly used in conjunction with digital splints to realign the toes if necessary. The patient should be reviewed after 1 week of the padding being applied in order to gauge its effectiveness.

Plantar fasciitis

In this condition the main sites of pain are along the medial bands of the plantar fascia and, in addition, there may be localised pain over the medial tubercle of the calcaneum. Pain is felt on initial weight bearing in the morning or after a period of rest. Prolonged walking gives rise to continuous pain along the medial longitudinal arch of the foot and may be crippling. There are various causes of this condition, of which the most common biomechanical condition is excessive abnormal pronation at the subtalar joint. A change of occupation to one that involves continuous standing or unaccustomed walking may be a contributing factor, as can a sudden excessive weight gain. In addition to the use of therapeutic laser or ultrasound therapy, the application of clinical strapping followed by orthotic therapy is required. As discussed earlier in this chapter, the use of figure-of-eight strapping to invert the calcaneum, either alone or in conjunction with a tarsal platform, is helpful. When the pain is primarily along the medial longitudinal arch and there is limited sign of abnormal pronation, the use of bow strapping is effective in providing short-term relief (Fig. 16.24). This reduces the tensile stress on the fascia, and therefore reduces the pain during weight bearing, and in addition takes up very little room in the shoe. Rigid strapping is used for this purpose in two widths: 2.5 cm (1 inch) for the bands running from the metatarsal head to the heel, and 3.75 cm ( inches) for the strapping across the plantar from the lateral to the medial sides of the foot.

Figure 16.24 Bow strapping for relief of pain in the plantar fascia.

March fracture

Although this condition may require orthopaedic intervention in the form of a walking plaster, relief from pain on weight bearing can be achieved in the short term, and sometimes for the duration of the treatment, by means of a 7-mm plantar metatarsal pad with a deep U cut-out over the affected metatarsal and held in place by a strapping.

Freiberg’s infarction

Surgical intervention is rarely attempted for this condition because it requires long-term therapy consisting of removal of pressure from the affected metatarsal head for up to 2 years in order to reduce deformity to a minimum. The optimum therapy is orthotic management, which should take into account not only removal of pressure from the affected area but any biomechanical malalignments that may be present (see also Ch. 4).

In the short term the padding of choice is a plantar metatarsal pad with a U cut-out to the affected metatarsal head, combined with a metatarsal bar to remove as much pressure as possible on weight bearing. It is important that shoe length be adequate and that no back pressure from the phalanx is referred to the metatarsal head. A shoe with a low heel should be advised.