Use of serial casting in the management of knee joint contractures in an adolescent with cerebral palsy.

W Phillips, MS, PT, PCS, is Neonatal/Neurologic Coordinator, Piedmont Hospital, 1968 Peachtree Rd

NW, Atlanta, GA 30309, and physical therapy consultant for the transition center for children with acquired brain injuries at Georgia State University, Atlanta, GA 30303. She was Staff Physical Therapist, Henrietta Egleston Hospital for Children, 1405 Clifton Rd NE, Atlanta, GA 30322, at the time this report was written. Address all correspondence to Ms Phillips at 444 Claire Dr NE, Atlanta, GA 30307 (USA).

M Audet, MMSc, PT, is Senior Physical Therapist, Henrietta Egleston Hospital for Children.

This article was submitted November 10, 1988, and was accepted April 21, 1990.

The clinical problems of adolescents with cerebral palsy are different from those of preschool- or school-aged children with cerebral palsy. Larger body size poses challenges to therapeutic handling and may require additional equipment or assistance. Fixed deformities such as joint contractures may not be improved by traditional therapeutic exercise. Results of previous surgeries must be considered. For example, an adolescent who has undergone a triple arthrodesis will not have ankle movement.

Long-standing dysfunctional patterns of family interaction may affect the patient's and the family's ability to carry out a prescribed home treatment program. In more complex treatment protocols, the patient's cognitive abilities may also affect compliance. Treatment goals should address improved function and prevention of deformities.

Serial casting has been used as an adjunct to the physical therapy management of preschool- and school-aged children with cerebral palsy.[1] During serial casting, the hyperactive muscle group is stretched to its maximal length, then immobilized in a lengthened position, and the antagonistic muscle group is immobilized in a shortened position. Casts are removed every few days to a few weeks. An attempt is made to gain additional length in the hyperactive muscle groups, and the casts are reapplied to maintain the new lengthened position.

A relationship between the use of serial casts and a reduction in reflex activity has been postulated.[2] The actual mechanism by which serial casting reduces reflex activity has not been identified. Pollack[3] proposed overcorrection of muscle length in casts so that the hyperactive muscle group is stretched to become more functional, whereas Wilson and Allen[4] suggested splinting overactive muscles to gain range of motion (ROM) or to control abnormal patterns of movement. Other researchers[5-7] have suggested that passive stretch may affect motoneuron excitability in a hyperactive muscle group. Changes in extensibility of muscle fibers have also been suggested as outcomes of casting.[8,9]

The purpose of this case report is to describe the use of serial casting in the management of severe knee joint flexion contractures in an adolescent with cerebral palsy.

Case Report

"TP" is a 15-year-old boy with a diagnosis of spastic diplegia who was first seen in our clinic in Henrietta Egleston Hospital for Children (Atlanta, Ga) 2 months following surgery for lengthening of the Achilles tendon. Although TP's gait was not evaluated by a physical therapist prior to surgery, his gait pattern was described by his parents and orthopedic surgeon as diplegic, with hip and knee flexion during the stance phase. During the swing phase of gait, he was said to have increased lateral trunk flexion toward the side of the stance limb, right hip internal rotation, and bilateral ankle pronation and plantar flexion. The right lower extremity demonstrated more abnormal movement than the left lower extremity. Because of abnormal weight bearing on the foot during ambulation, TP had been having difficulty with skin breakdown on the medial surface of the plantar aspect of his feet.

Prior to surgery, TP ambulated independently and his standing balance and endurance were sufficient for activities such as throwing a basketball into a hoop. He was independent in activities of daily living and attended a school for learning-disabled individuals close to his home. Following surgery, TP was equipped with bilateral long leg cylinder casts, which immobilized the knees only. While wearing the casts, he was able to ambulate without assistance. At the time of cast removal, TP was no longer able to ambulate. This inability to ambulate may have been secondary to atrophy of the quadriceps femoris muscles. He was referred to an adult orthopedic physical therapy clinic for evaluation and exercise. TP was not compliant with his exercise program and spent most of his time sitting in a wheelchair. TP's parents were unable to manage his exercise program or behavior.

TP's physical therapist in the adult orthopedic clinic noted that the resistance of his hamstring muscles to lengthening increased over the first few weeks following cast removal. Over a 2-month period, severe knee flexion contractures developed. TP was also noncompliant in the use of prescribed bilateral ankle-foot orthoses (AFOs).

TP was referred to our physical therapy department to attempt to regain lost ROM and function. At the time of admission, TP's range of prone knee flexion was 90 to 135 degrees on the right side and 74 to 134 degrees on the left side, with his hamstring muscles resistant to passive ROM at the knee.

TP's upper extremity and trunk strength appeared to be functionally within normal limits. He was able to assume a standing position with hip and knee flexion and to maintain the position independently using a walker. This task was achieved primarily by use of his upper extremities, with little weight bearing on the lower extremities. TP's gait pattern was not functional. in a standing position, he was unable to shift his weight to advance his lower extremity forward. He was able, however, to transfer from his wheelchair to his bed and return independently.

TP was admitted to our hospital for a short rehabilitation stay. Bilateral cylinder plaster casts were applied according to our casting protocol. The skin was first inspected for integrity. Any breakdown or pressure areas were considered a contraindication to cast application. While TP was positioned prone, his skin was cleaned and dried and a 7.62-cm (3 in) stockinette was applied from 5.08 cm (2 in) distal to the medial malleoli to the gluteal folds. Foam padding, 0.635 cm (0.25 in) thick and 1.27 cm (0.5 in) wide, was applied over the fibular head and patella and circumferentially at the level of the malleoli. Cast padding was then applied circumferentially from just proximal to the malleoli to just proximal to the gluteal folds, allowing a 1.905-cm (0.75-in) overlap. Three to four layers of plaster were then applied by one therapist (MA) as a second therapist (WEP) applied a stretch to the hamstring muscles. Finally, the cast edges were finished just proximal to the malleoli and at the level of the gluteal folds according to our departmental protocol.

The nursing staff was instructed to perform neurovascular checks. Testing for pedal pulses every 3 hours, observing toe nail-bed color, and testing for temperature of the exposed skin are the components of our hospital protocol. TP was also instructed not to stand for at least 12 hours following cast application. TP wore the casts 24 hours per day.

The casts were changed initially after 24 hours and subsequently at 48- to 72-hour intervals. Twenty-four hours after each cast application, the anterior portion of the cast was removed distal to the knee. TP was then instructed to lie prone for 40 minutes three times a day in order to use the assistance of gravity to stretch the hamstring muscles and knee joint capsule. Weights 0.9072 kg [2 lb]) were applied daily for 20 minutes to the ankle in the prone position to enhance the effect of gravity. Other components of TP's twice-daily physical therapy program included exercises in the prone position with his chest supported on a roll and weight bearing on his upper extremities. From this position, TP worked on assuming a sitting position with the assistance of his physical therapist for balance. He also worked on actively extending his hip while rotating his pelvis posteriorly as he moved to the sitting position. He received passive heel-cord stretching daily. Quadriceps femoris and hip abductor muscle strengthening exercises were also included.

By the time of the second cast change (October 23, 1987), TP was able to tolerate standing in the parallel bars; however, we believe this tolerance was achieved by bearing most of his weight on his upper extremities. He progressed to ambulation in the parallel bars without assistance. By the time of the third cast change (October 26, 1987), he was able to ambulate using a rolling walker for assistance.

TP required seven cast changes over a 21-day inpatient stay. Passive knee flexion measurements at the time of cast changes are shown in the Table. Goniometric ROM measurements were taken by both therapists (WEP and MA) following three castings. First, TP was positioned prone. His pelvis was then stabilized as the knee was extended by one therapist and the knee flexion measurement was taken by the other therapist, and vice versa. Intertester agreement within 4 degrees was determined to be acceptable.

TP was measured for long leg braces prior to application of the final casts but was discharged from the hospital in cylinder casts with additional reinforcement; these casts were worn 24 hours per day. Final passive knee flexion measurements were 13 to 138 degrees on the right side and 9 to 135 degrees on the left side, an improvement of 77 and 65 degrees, respectively.

TP wore the final casts for approximately 3 weeks until the long leg braces were fabricated. He used the braces as night splints until his first clinic visit. His parents were instructed in stretching exercises for the hip adductor, hip flexor, and hamstring muscles in the interim. When he was seen at the clinic 4 weeks after discharge, he was ambulating independently without his braces using two straight canes and without excessive hip flexion, knee flexion, or hip internal rotation; his heels were flat during the stance phase of gait. Active dorsiflexion at heel-strike was not achieved.

The long leg braces subsequently were used as night splints only. TP was followed weekly for a program of lower extremity stretching and ROM, as well as strengthening exercises for his quadriceps femoris, hip abductor, hip extensor, and trunk musculature. TP's ability to cooperate during treatment improved. He performed his home program of household ambulation daily and used the long leg braces as night splints every night. He was eventually able to resume bicycling independently. TP currently ambulates without canes or braces.

Conclusion

The results of the treatment protocol described in this case report indicate that serial casting may be a useful component in the treatment of adolescents with cerebral palsy for whom flexion contractures are a problem. The mechanism by which casting produces an effect has not been identified conclusively. Stretching of the knee joint capsule, along with a decrease in length in the quadriceps femoris muscle group, may have allowed the quadriceps femoris muscles to increase in strength and to function more effectively. in a lengthened position, the hamstring muscles may have been placed at a mechanical disadvantage and made a less effective antagonist.

TP's improvements may be attributed at least in part to his intensive twice-daily exercise and gait training program as well as serial casting. Further research to determine the effectiveness of serial casting in patients with cerebral palsy is needed. An investigation of the utility of serial casting in the treatment of other patient populations for whom muscle contractures are a problem would be useful.

References

1. Sussman MD, Cusick B. Preliminary report: the role of short-leg, tone-reducing casts as an adjunct to physical therapy of patients with cerebral palsy. Johns Hopkins Med J. 1979;145:112-114.

2. King TI. Plaster splinting as a means of reducing elbow flexor spasticity: a case study. Am J Occup Ther 1982;33:671-673.

3. Pollack GA. Surgical treatment of cerebral palsy. J Bone Joint Surg Br. 1962;44:68-81.

4. Wilson BDR, Allen D. Splints in the treatment of cerebral palsy. Physiotherapy. 1962;48:41-44.

5. Angel RW, Hoffman WW. The H-reflex in normal, spastic and rigid subjects. Arch Neurol. 1973;8:591-596.

6. Devanandan MS, Eccles RM, Yokata T. Muscle stretch and the presynaptic inhibition of the group la pathway to motoneurones. J Physiol Lond. 1962;79:430-441.

7. Mark RF, Coquery JM, Paillard J. Autogenic reflex of slow or steady stretch of the calf muscles in man. J Neurol Neurosurg Psychiatry. 1982;45:669-701.

8. Tardieu E, Juet de la Tour E, Bret MD, Tardieu G. Muscle hypoextensibility in children with cerebral palsy: clinical and experimental observations. Arch Phys Med Rehabil. 1982;63:97-102.

9. Tabary JC, Tabary C, Tardieu G, Goldspink G. Physiological and structural changes in the cat's soleus muscle due to immobilization at different lengths by plaster casts. J Physiol Parts. 1972;224:231-244.