Management of Limb Contractures and Deformity
The management of limb contractures in progressive neuromuscular disease and the role of stretching, orthotics, and surgery has recently been comprehensively reviewed (130). Contracture is defined as the lack of full active of passive range of motion (ROM) due to joint, muscle, or soft tissue limitation.
Contractures may be arthrogenic, soft tissue, or myogenic in nature, and a combination of intrinsic structural changes of muscle and extrinsic factors leads to myogenic contractures in selected neuromuscular disease conditions. These factors include the following: degree of fibrosis and fatty tissue infiltration; static positioning and lack of full active and passive range of motion; imbalance of agonist and antagonist muscle strength across the joint; lack of upright weight bearing and static positioning in sitting; compensatory postural changes used to biomechanically stabilize joints for upright standing; and functional anatomy of muscles and joints (multijoint muscle groups in which the origin and insertion crosses multiple joints). In general, dystrophic myopathies have a high degree of fibrosis and fatty infiltration, placing these patients at higher risk for contractures. Significant contractures have been most commonly identified in Duchenne muscular dystrophy, Becker muscular dystrophy, Emery- Dreifuss muscular dystrophy, congenital muscular dystrophy, autosomal recessive LGMD, FSHD muscular dystrophy, myotonic muscular dystrophy, hereditary motor sensory neuropathy, and spinal muscular atrophy.Contractures and progressive NMD conditions should be managed with the following concepts in mind:
1. Prevention of contractures requires early diagnosis and initiation of physical medicine approaches, such as passive ROM and splinting wall contractures, are still mild.
2. Contractures are inevitable in some NMD conditions, such as DMD.
3. Advanced contractures become fixed and show little response to stretching programs.
4. A major rationale for controlling contractures of the lower extremity is to minimize the adverse effect of contractures on independent ambulation. However, the major cause of wheelchair reliance in NMD is generally weakness, not contracture formation.
5. Static positioning of both upper and lower extremity joints in patients with weak musculature is the most important cause of contracture formation.
6. Passive stretching for control of lower limb contractures is most successful in ambulatory patients with early mild joint contractures.
7. Upper extremity contractures may not negatively affect the function if they are mild.
8. Joint range of motion should be monitored regularly by physical therapists and occupational therapists using objective goniometric measurement.
Principle therapy modalities must be regularly carried out to prevent or delay the development of lower extremity contractures for those at risk for musculoskeletal deformity. These include: regularly prescribed periods of daily standing and walking if the patient is functionally capable of being upright; passive stretching of muscles and joints with a daily home program; positioning of the leg to promote extension and oppose joint flexion when the patient is non-weight bearing through the lower extremities; and splinting, which is a useful measure for the prevention or delay of ankle contracture.
In the upper extremity, elbow flexion contractures in dystrophic myopathies may occur soon after transition to the wheelchair, secondary to static positioning of the arms and elbow flexion on the armrests of the wheelchair (9). Other associated deformities in DMD and other dystrophic myopathies include forearm pronator tightness and wrist flexion-ulnar deviation in the later stages of the disease. The regular palmdown position of the hand increases the occurrence of forearm pronator contracture.
Mild elbow flexion contractures of ≤ to 15 degrees are of no functional consequence to the patient using crutches or a wheelchair. Contractures of the elbows over 30 degrees can interfere with the use of crutches in ambulatory patients with NMD. Severe elbow flexion contractures of >60° are associated with decreased distal upper extremity function and produce difficulty when dressing.Passive stretching of the elbow flexors may be combined with passive stretching into forearm supination to help prevent contractures. Prophylactic occupational therapy management of the wrist and hand is recommended in NMD to slow the development of contractures and to maintain fine motor skills. Daily passive stretching of the wrist flexors and intrinsic and extrinsic muscles of the hand and wrist are recommended, as are active range-of-mo- tion exercises for the wrist and long finger flexors. Nighttime resting splints, which promote wrist extension, metacarpophalangeal extension, and proximal interphalangeal flexion, are recommended. Daytime positioning should emphasize wrist and finger extension, but any splinting should not compromise sensation or function.
Shoulder contractures are less problematic in patients with profound proximal muscle weakness. Combined shoulder internal rotation, adduction contracture, and elbow flexion deformity may interfere with self-feeding. Severe shoulder internal rotation deformities may complicate dressing, produce pain on passive range of motion, and cause pain during sleep.