CHAPTER 125
Tissue Remodeling and Contracture Correction Using Serial Plaster Casting and Orthotic Positioning

JUDITH A. BELL KROTOSKI, MA, OTR/L, CHT, FAOTA

Pathomechanics: Inevitability of Gradualness

Contracted joints and soft tissues can be remodeled and contractures corrected through the serial application of plaster casts or orthoses that hold the shortened tissue or joint at the end of its available length or range of motion (ROM) for a prolonged period of time. Through serial reapplication of the plaster cast or orthosis the tissue gradually elongates, resulting in correction of joint and soft tissue contractures and/or muscle-tendon unit tightness.1,2

Serial plaster orthotic positioning or casting for contracted joints or soft tissues began with Paul Brand in his use of plaster casting of clubfeet in children. He began to understand that the initial benefits of forceful correction with “wedge casting” were often undone by deep tissue scarring and later tissue contraction, and was sure that there must be a way of correcting a joint deformity without such damaging force on the tissues and on the child. Once Brand relocated from medical school in England to India, he observed there that adults with clubfeet that had never been corrected still had supple joints.

Under Brand’s direction, an infant with a clubfoot deformity was put to nursing while plaster of Paris was placed in single layers directly on the foot to be corrected. The foot was gradually moved into a corrective position while the plaster was setting until the child turned his or her eyes and “looked.” Correction of the foot always would stop before the point at which the child would begin to cry signaling distress. The foot would be held in this position gently but firmly, and the plaster allowed to set. Frequent successive recasting using the same procedure resulted in correction of the deformity—and a healthy joint! The method was so successful that the idea was applied to the interphalangeal (IP) joints of severely clawed hands found in patients with Hansen’s disease (leprosy) at The New Life Center established by Brand, in Vellore, India.^2-4 The technique met with equal success in these patients, who were thought beyond hope from medical intervention. The technique has continued to be successful for any small or large contracted joint or soft tissue. It works to lengthen the skin and contracted soft tissue, including vessels and nerves, and muscle-tendon units, for single or multiple joints. Plaster’s conforming properties make it ideal for orthotic positioning, since it distributes forces throughout the length of the cast, eliminating points of pressure under the cast.

Growth Not Stretching

The serial casting/positioning technique described by Brand is not one of progressive “stretching” but of “growth of tissue.” Forceful stretching of soft tissue can cause tissue damage resulting in inflammation and later scar formation. The remodeling process, in contrast, takes time, thus the contracted joint or tissue must be held in a lengthened position for a period of time. The contracted tissues are stimulated to gradually elongate by being held at the maximum possible length. Each day or every other day, the cast or orthosis is removed and the joint or soft tissue can then be repositioned at a greater length. Through this serial casting or positioning method, the joint, soft tissue or muscle-tendon unit contracture may be gradually corrected over a period of days or weeks. In support of this approach, Eppenstein et al.⁵ documented research demonstrating that low-load, long-duration tension is optimal in reducing the risk of tearing soft tissue, increasing residual elongation, and providing more permanent realignment of collagen fibers into a more parallel orientation.

Steve Kolumban,^6,7 a therapist working with Brand at the Christian Medical College and Hospital in Vellore, India, compared night orthotic positioning with regular physiotherapy technique in 24 outpatients with contractures of the IP joints. Regular physiotherapy consisted of wax baths, oil massage, and exercise (passive and active-assistive). At the end of the study the group with the orthotic positioning had significantly superior results. The percentage of degrees straightened from the total possible number was 45.7% with orthotic positioning and 0.9% without it. Of the 25 fingers in the group without orthotic positioning, 12 joints ended with a greater contracture than that with which they began.

Later Kolumban⁸ compared cylinder serial plaster casting with dynamic orthotic positioning. The study matched fingers from both groups into pairs of six variables: age, contracture angle, joint resiliency, length of the finger, length of orthotic positioning, and applied straightening force. A straightening force of 250 g was applied in both methods of positioning. At the end of the study the results showed a strong indication that the casting was superior to dynamic positioning. Of 26 patients with 52 contracted IP joints, the percentage of degrees straightened from the total possible with serial cylinder plaster casting was 47.8% and with dynamic orthotic positioning, 34.9%. Important to note is that there were no injuries to the involved tissues (many of the patients had anesthetic hands) resulting from the plaster casting, and there were seven injuries with dynamic orthotic positioning.

The technique was adopted by hand surgeons in England and used for joint and tendon contractures after war injuries.⁹ Brand brought the technique to the United States in the treatment of patients with Hansen’s disease when he relocated to the U.S. Public Health Service Hospital in Carville, Louisiana, and in his worldwide tours and lectures. Under his direction in 1973, I used the serial cylinder casting technique for IP joints of the hand, and adapted it to be removable at the New Orleans U.S. Public Health Service Hospital for seamen. In 1976, having relocated to the Center, I introduced the casting techniques to the Philadelphia Hand Center, Ltd., in Pennsylvania, for patients with a wide variety of conditions resulting in joint contractures of the hand. Conditions in which the casting has been used successfully to reduce finger contractures include arthritis, reflex sympathetic dystrophy, Dupuytren’s contracture, congenital contractures, joint dislocations, burns, boutonnière deformities, swan-neck deformities, and contractures after fractures and tendon repairs.

Brand and Kolumban, as well as Eppenstein et al., emphasized the importance of pre- and postcasting measurements, with fixed repeatable positions for measurement. If active and passive finger extension is recorded before casting with the wrist in neutral, the same position should be used postcasting. In assessing finger stiffness and contracture, Brand used passive controlled tension measurements with the wrist in flexion, neutral, and extension to differentiate joint tightness, versus muscle-tendon unit tightness. Before using serial casting or orthotic positioning, a therapist should determine the underlying cause of the limitation, whether joint contracture, muscle contracture, nerve injury, or spasticity.

Indications for Serial Plaster Casting or Orthotic Positioning

Advantages of Casting for Tissue Remodeling

Swelling is never increased by the plaster cast and is often decreased because the cast keeps the joint still for periods of rest. In contrast, dynamic mobilization orthotic positioning can cause an increase in swelling when the force is too high or the finger cuff or straps are too tight. Because casting does not forcefully stretch the tissue, pain is not increased by serial casting and is often decreased. This is particularly important in patients with complex regional pain syndrome, in whom even a slight increase in pain is a step in the wrong direction. Cylinder casting can be used over lacerations and ulcers. The technique has been found useful with insensitive fingers in particular, so that they can heal without further trauma. Plaster allows the skin underneath to breathe and does not macerate the skin if applied directly, and may be better tolerated than other positioning materials. The plaster allows some air to the wound and absorbs tissue exudates.

Used correctly, casting is a nontraumatic way of gaining additional flexion or extension range. Circulation of the finger is always checked after cast application to make sure the vascular supply is not compromised. The patient is always instructed to remove the cast later if it appears too tight, but this is rarely necessary.

Materials

Plaster of Paris (amorphous anhydride calcium sulfate) is readily available and cost-effective, making it adaptable to a variety of circumstances including hospital wards and intensive care units. When water is added to the plaster it can be conformed precisely to the target joint or tissue in the desired position. Once it hardens the plaster orthosis or cast maintains the position securely. Johnson & Johnson developed the Specialist Plaster Bandage, which is recommended due to its fast setting and ease of casting (Johnson & Johnson, Smith & Nephew Rolyan, and Carpace and Lohmann).10 The types of plaster of Paris used are fast-setting (5–8 minutes) and extra-fast-setting (2–4 minutes). Gypsona was used by Brand and still liked by many clinicians; however, its product literature warns against direct application to the skin due to heat produced during setting. The clinician needs to carefully read all product literature and follow instructions for safe use of any material.^11-13

One needs to be aware of the thermal effect of plaster during setting. The temperature of the water used for wetting the plaster should be cool, since hot water can increase temperature on setting of the plaster.^11,13 Generally temperature peaks between 5 to 15 minutes after application. Heat produced is somewhat relative to the number of layers used, thus very thin layers can usually be applied directly to the skin. For finger casts, no more than one to two layers in what Brand called “eggshell casting” are needed.² For wrist and forearm casts, six to eight layers, slightly padded, are usually sufficient.^5,14 Strength can be improved by additional accordion-type folds or layers added specifically at the wrist or thumb. While allergic reactions are relatively rare, the clinician needs to be mindful of the possibility from plaster or any material placed in contact with the skin. During and after casting one should routinely monitor the skin for possible irritation.¹²

Serial Cylindrical Casting

Serial cylinder casting can be used to increase joint ROM in either flexion or extension and is most commonly applied to the proximal IP (PIP) joint. Optimally the cast is changed every other day (Fig. 125-1). It is important to mobilize joints briefly during cast changes. Paraffin wax or other thermal modalities can be used, followed by a brief session of manual exercise and mobilization before the cast is reapplied. It is expected that with each cast change the involved tissues or joint(s) can be positioned further in the desired direction of flexion or extension.

Method

Non-gypsona plaster of desired length is dipped in water (usually room temperature) and dried on a paper towel slightly. This will remove excess water, makes it easier to handle and wrap, and minimizes drip. The cast can be made all in one piece wrapped distally from the base to the tip of the finger, or in two pieces cut from the 1-inch-wide plaster in 12- to 15-inch lengths. Start with folding the gauze plaster edge that will first be in contact with the finger about the width of the finger (Fig. 125-2). Begin wrapping from the base of the finger, in an overlapping fashion (Fig. 125-3A and B). Then reverse, fold the gauze plaster edge the width of a finger, and start the second wrapping from the tip of the finger to just beyond the level of the IP joint. In this way the last bit of cast material can often be placed just under the IP joint for a little extra support (while not making the cast too thick). If it is desirable to be able to remove the cast, the very tip of the cast can be left open. In either method, just before the strip of plaster is applied to the hand, a slight fold on the edge of the plaster strip will make a smooth rather than a rough edge against the finger web and volar distal edge of the cast. This slight fold can be made wherever there will be an edge to the cast.

The plaster is wrapped just proximal to the distal IP (DIP) joint crease if later DIP joint movement is desired, and it is wrapped past the DIP joint crease in the following cases:

The profundus tendon is tight when casting for extension.

The extensor mechanism is tight when casting for flexion.

The improvement in ROM is also desired at the DIP joint.

How to Assure Correction of the PIP Joint Position

While wrapping the cast, the joint or joints are moved gently into the corrected position. While the plaster sets, the position is held and the plaster smoothed with a continuous motion of the fingers, which helps to avoid pressure areas in the cast. The finger is supported in extension while wrapping if the cast is being used to increase extension, and in flexion while wrapping if the goal is to increase IP joint flexion. A useful technique after the cast is wrapped is to maintain a corrective tension on the joint as the cast sets. This is accomplished by stabilizing the metacarpophalangeal (MCP) joint in 90-degree flexion, while the other hand lightly pinches the tip of the finger being casted. In this way, one can effectively apply a distraction to straighten the PIP joint. This distraction is enough to gently elongate the finger (Fig. 125-4).

How to Avoid Adding Force

Why Absent or Minimal Padding?

How Often to Change the Cast

How to Remove a Cast Left on

Cylinder casts can easily be removed by immersing the hand in water, finding the edge, and unwrapping, or by squeezing the cast from side to side. Alternatively, the cast that has not been soaked can be cut along its dorsal surface with thin blunt-tipped scissors. Suture scissors or wire snips (with blunted tips) work well to remove the cast.

Removable Cylinder Casts

Occasions arise when it is desirable to make the serial cylinder casts removable by the patient for exercise. The most obvious cases are those in which it is most important to move tendons frequently to prevent adhesions, for example, following tendon repair or when the patient can attend therapy only infrequently.15,16 By making the cylinder casts removable, one can often improve flexion ROM by exercise during cast change, while using the technique for casting of the finger into extension.

A cast can be made removable if removed and replaced immediately after it is firmly set. After the cast is firm, one should grasp along the length of the cast and gently loosen and remove it from the finger. It is important to note that the cast must be removed at this point if it is going to be removable for exercise of the joint (Fig. 125-5). The finger and cast should be continually checked for points of pressure. If necessary, the edge of the cast can be trimmed slightly for clearance of MCP or DIP joint flexion. The examiner should clean the excess plaster off the finger, optionally apply a light coat of lanolin to the finger, and replace, or allow the patient to replace the cast.

If the IP joint is too swollen to allow easy removal of the cast, a small cut can be made in the dorsal radial portion of the cast at the proximal phalanx. This cut is extended toward the IP joint until the cast can be removed (Fig. 125-6). After the cast is removed, the cut edges can be trimmed slightly and the cast replaced without the finger joint losing correction (Fig. 125-7).

If the finger joint is in a position of too much flexion to allow removal of the cast, one can make a window in the cast with scissors by first making cuts in the dorsoradial and dorsoulnar sides of the cast at the proximal phalanx. The flap is lifted, and the cast is removed (Fig. 125-8A-D). The flap is trimmed with scissors, and the cast can then be replaced and secured at the proximal phalanx with a small strip of paper tape (Fig. 125-9).

Plaster Casting for Dorsal PIP Joint Wounds or Webbed Fingers

An alternative casting method with a hand-based extension was developed by Brand for increased stability of the PIP joint when needed for casting a dorsal PIP joint wound, or casting for improved ROM when the fingers are webbed. When there is a wound over the PIP joint, casting may add additional pressure on the dorsum of the PIP joint if the cast migrates forward. This happens because the wound is usually dressed, and the plaster contact with the skin is decreased, allowing padding and the plaster cast to shift and cause shear pressure when the fingers are used. Webbed fingers decrease the length of the proximal phalanx that can be casted, and sometimes the proximal portion of the cast is not long enough to keep it from rotating forward on the finger, causing additional pressure over the DIP joint. A plaster or thermoplastic volar extension including the volar MCP joint will increase support and prevent dorsal PIP joint pressure (Fig. 125-10).

This palmar extension method of casting is particularly well suited to IP joint wounds, including for those patients with dorsal PIP joint burns (often involving the extensor mechanism dorsal hood), because the volar slab can be made to be left in place when the cylinder cast is removed and replaced, limiting movement at the PIP joint. The slab can stay in place because the cylinder cast, which is applied after the slab has set, can be cut and peeled off the slab. When used for wounds such as burns, the casting is used to maintain rather than increase ROM and to limit movement of the joint except when absolutely necessary.

Casting for Correction of More Than One Joint in Two Planes of Movement: Flexion and Extension

Plaster casting can be coordinated with other conventional forms of orthotic positioning (Fig. 125-11), and this is particularly helpful in the treatment of fingers that require correction at more than one joint and in two planes of movement, such as fingers with swan-neck deformities, boutonnière deformities, and IP joint flexion contractures as seen after nerve injuries and with complex regional pain syndrome (Fig. 125-12A and B)

Casting a swan-neck deformity into extension at the DIP joint permits the PIP joint to be more easily casted into flexion in a second stage, with the added advantage that there is no examiner finger or orthosis pressure at the dorsal IP joint during casting. (The DIP joint is already protected in a cast, which now can be safely held by the examiner during the second stage of casting [Fig. 125-13A and B].) In the case of a boutonnière deformity, the PIP joint is casted in maximum extension, which results in the lateral bands becoming slightly relaxed, allowing increased flexion of the DIP joint for casting in a second stage. (The PIP joint is already protected in a cast, which now can be safely held by the examiner during the second stage of casting.) Flexibility in application is needed and is tailored to individual situations. When the PIP joint of the finger is casted for extension, the DIP joint is often included in the cast. But the DIP joint can be left out intentionally, to allow DIP joint flexion exercises if desirable (see Fig. 125-1).

Casting for Dynamic Transfer of Moment

Brand also described the use of casting to block motion or transfer motion to other joints in the same or another plane of movement.2,16,17 An immobilization orthosis is thus not always “static” in effect. It can “dynamically” function to shift motion to joints adjacent to the casted joint during hand movement. For example, casting only the DIP joint for a stiff PIP joint allows the full power of the flexor digitorum profundus to be able to act on the PIP joint and enhance efforts at PIP joint flexion (Fig. 125-14).

Following intrinsic replacement transfers the patient often will demonstrate undesired flexion at the IP joints with early attempts at activating the transfers. Casting and restricting IP joint motion will enhance tendon transfer training and MCP joint flexion (Fig. 125-15).

Casting of only the PIP joint is necessary in the postoperative phase of a boutonnière deformity repair or reconstruction. The cast protects the repair or reconstruction by limiting PIP joint flexion. The DIP joint is left free, allowing DIP joint flexion exercise, which promotes early limited gliding of the reconstructed or repaired extensor mechanism (see Fig. 125-1).

Casting of Other Joints and Muscle-Tendon Units

The technique of plaster casting described in the serial cylinder casting section for PIP joint contractures can be used on any joint, muscle-tendon unit, or other soft tissue contractures. Muscle-tendon unit contractures usually require slab casting to incorporate the full length of the muscle-tendon unit in the cast. For example, casts to lengthen finger flexor muscle-tendon unit shortening are made in two stages; a volar slab (six to eight layers), and once set and cooled, followed with a circumferential cast (one to two layers). The plaster slab for the volar wrist and forearm is generally applied over light padding and/or stockinette. The plaster used to secure the volar slab is applied circumferentially about the dorsal aspect of the forearm and is left unpadded. Just as in the serial cylinder finger casting technique, the sticking of the cast to the skin is desired to distribute point pressures, and hold the position exactly for tissue remodeling to occur.

A volar plaster slab can be used immediately after surgery for tendon transfers to serially adjust the positioning of the fingers and wrist for optimum mechanical advantage. For example, adjustments are made to address transfers that are initially too tight by serially repositioning the joints crossed by the transfer to reduce the tightness (Fig. 125-16).

How to Measure and Document Improvement

Improvement in soft tissue mobility and joint ROM for all joints can be quantified by ROM and torque angle measurements before the application of the plaster cast or orthosis. Each time the cast is removed, measurements are recorded before application of the next cast. In this way, changes in ROM are documented and treatment efficacy can be evaluated.2,4,8,18

Serial Plaster Slabs

Serial-static plaster orthoses have many applications in the management of complex hand injuries. Volar plaster slabs are used to reduce extrinsic flexor tendon tightness, and dorsal plaster slabs for extrinsic extensor tendon tightness (Fig. 125-17).^2,19 Either volar or dorsal slabs can be used for MCP and wrist joint tightness depending on the direction of tightness. For example, with a limitation in wrist extension secondary to a volar wrist scar contracture, a volar slab is used with the wrist positioned in maximum extension. With limited MCP joint flexion a dorsal slab can be used with the MCP joints positioned in maximum flexion. When tightness of the intrinsic muscle-tendon units is apparent, a plaster orthosis that positions the MCP joints in extension and the PIP and DIP joints in flexion can be used. Thumb webspace contractures can similarly be corrected by serially casting the thumb webspace.

Technique of Applying Plaster Slabs

Six to eight strips of plaster are cut to the width of the hand and forearm either from plaster gauze packaged in slabs or rolls (rolls are rolled out and made into a slab). The slab should include the hand and two thirds of the forearm (Fig. 125-18). If needed for a large arm, two sets of plaster strips can be overlapped for desired width. If the thumb is included, a 3- to 4-inch by 2-inch section of plaster gauze can be interspersed in the layers of plaster before it is wet. The corners of the slab can be rounded at the fingers and thumb, or a cut-out area made for the base of the thumb if not to be included in the slab. Any sharp or pointy edge is to be eliminated by folding or cutting the plaster. Stockinette or cast padding is best applied to the arm before molding so it becomes incorporated into the plaster slab on molding (Fig. 125-19). Padding added later is used with great care as it adds bulk to the plaster, and can become a source of pressure (Fig. 125-20). Silastic gel or elastomer padding sometimes works incorporated into a cast, but it occludes air. Silastic gel pads for insoles are readily available at most pharmacies (Fig. 125-21).

The plaster slab is immersed in water for 5 to 10 seconds, then removed and lightly squeezed, or dried slightly on a paper towel to remove the excess water. The plaster is smoothed while unfolding it and shaping. Once wet, the six or more layers of plaster will become one unit. The plaster is molded and shaped to the arm while maintaining the desired position with attention paid to the arches of the hand and webspaces if included in the orthosis or cast. The plaster is allowed to conform around bony prominences, with care taken to not add any finger point pressure, which can later cause tissue irritation. The wrist is positioned first, then the fingers. It is important to apply uniform pressure and maintain the position of the wrist and fingers during molding and setting of the plaster. A gentle tension is applied until the plaster is set. Rough edges are trimmed, and the cast padding or stockinette is overlapped over the plaster. If tape is used, it must adhere back onto itself, as it does not stick to wet plaster. Thin Elastoplast (Beirsdorf-Jobst Inc., Rutherford College, North Carolina) is sometimes used to finish edges.

The plaster slab is secured with a roll of thin plaster, an elastic bandage, or bias-cut stockinette. The tips of the fingers should be left visible to observe circulation. The slab is changed every 2 to 3 days, or at least once a week.

Special Considerations

How to Remove Plaster Slabs

Other Applications as Indicated

Since the technique described can be used for any joint or soft tissue contracture, applications vary widely and can be considered as indicated by need. For example, the MCP joints can be casted into flexion by a modified circular casting technique (Fig. 125-22).¹⁹