Duchenne Muscular Dystrophy: Rehabilitation Management

1. Duchenne Muscular Dystrophy:Rehabilitation Management

2. Introduction • Different types of rehabilitation needed through life • Delivered mainly by physiotherapists and occupational therapists, but others may be involved • Rehabiliation specialists • Orthotists • Providers of wheelchairs/other seating • (Potentially) orthopaedic surgeons • Key: management of muscle extensibility and joint contractures • Stretching aims to preserve function and maintain comfort • Programme should be monitored by PT, but must become part of the family’s daily routine

3. Contractures • Factors contributing towards tendency towards contractures: • Muscles becoming less elastic due to limited use/positioning • Muscles out of balance around the joint • Maintaining good range of movement and symmetry is important • Maintains best possible function • Prevents development of fixed deformities • Prevents pressure problems with the skin

4. Management of muscle extensibility and joint contractures • Physiotherapist: key contact for contracture management • Ideally input from local PT supported by a specialist PT every 4 months • Stretching should be performed at least 4-6 times a week as part of family’s daily routine • Effective stretching may require a range of techniques including stretching, splinting, and standing devices

5. Stretches • Regular ankle, knee and hip stretching is important • Later, regular stretching at the arms becomes necessary – especially fingers, wrist, elbow and shoulder • Additional areas requiring stretching may be identified on individual examination • Standing programes (in a standing frame, or power chair with stander) are recommended after walking becomes impossible • Resting hand splints are appropriate for individuals with tight long-finger flexors

6. Splints • Night splints (ankle-foot orthoses/AFOs) can help control ankle contractures • Should be custom-made, not “off the shelf” • After loss of ambulation, daytime splints may be preferred • Daytime splints not recommended for ambulant boys • Long-leg splints (knee-ankle-foot-orthoses) may be useful at stage when walking is becoming very difficult or impossible • Can help control joint tightness, prolong ambulation, and delay the onset of scoliosis

7. Wheelchairs, seating and assistive equipment • Early ambulatory phase • Scooter, stroller, or wheelchair may be used for long distances to conserve strength • Posture is important: customisation of chair normally necessary • With increased difficulty walking, provision of powered wheelchair is recommended • This should be adapted/customised for comfort, posture and symmetry

8. Wheelchairs, seating and assistive equipment (2) • Arm strength becomes an issue over time • PTs/OTs can recommend assistive devices to maintain independence (e.g. alternative computer/environmental control access) • Proactive consideration of equipment allows timely provision • Additional adaptations in late ambulatory and non-ambulatory stages may be needed to help with getting upstairs, transferring, eating/drinking, turning in bed, and bathing

9. Recommendations for exercise • Limited research on type, frequency, and intensity of exercise that is optimum for DMD • High-resistance strength training and eccentric exercise are inappropriate across the lifespan • Concerns about contraction-induced muscle-fibre injury • To avoid disuse atrophy and other secondary complications of inactivity, all ambulatory and early non-ambulatory boys should participate in regular submaximal (gentle) functional strengthening/activity, including a combination of swimming-pool exercises and recreation-based exercises in the community

10. Recommendations for exercise (2) • Swimming may benefit aerobic conditioning and respiratory exercise: highly recommended from early ambulatory to early non-ambulatory phases (can be continued as long as medically safe) • Additional benefits may be provided by low-resistance strength training and optimisation of upper body function • Significant muscle pain or myoclobinuria in 24h period after a specific activity is a sign of overexertion and contraction-induced injury. If this occurs, the activity should be modified

11. Surgery: Introduction • No unequivocal situations where contracture surgery is invariably indicated • May be appropriate in some scenarios if lower-limb contractures are present despite range-of-motion exercises and splinting • Approach must be strictly individualised • Ankles (and to a lesser extent, knees) are most amenable to surgical correction/subsequent bracing • Hip responds poorly to surgery for fixed flexion contractures; cannot be effectively braced. Surgical release/lengthening of iliopsoas and other hip flexors may further weaken them, and make the patient unable to walk even with contracture correction. • In ambulant patients, hip deformity often self-correcting if knees/ankles straightened • Various surgical options exist: none can be recommended above any other.

12. Surgery: Early Ambulatory Phase • Procedures for early contractures include • Heel-cord (tendo-Achilles) lengthening for equinus contractures • Hamstring tendon lengthening for knee-flexion contractures • Anterior hip-muscle releases for hip-flexion contractures • Some clinics recommend that procedures are done before contractures develop: this approach is not widely practiced today

13. Surgery: Middle Ambulatory Phase (1) • Interventions aim to prolong ambulation: contracted joint can limit walking even if overall limb musculature has sufficient strength • Some evidence suggests walking can be prolonged 1-3 years by surgery • Difficulty of objective assessment: consensus difficult to achieve • Prolonged ambulation due to steroid use has further increased uncertainty of value of corrective surgery • Certain recommendations can be made irrespective of steroid status • Muscle strength/range of motion around individual joints should be considered before deciding upon surgery

14. Surgery: Middle Ambulatory Phase (2) • Approaches to lower-extremity surgery • Bilateral multi-level (hip-knee-ankle/knee ankle) procedures • Bilateral single-level (ankle) procedures • Rarely, unilateral single-level (ankle) procedures for asymmetric involvement • The surgeries involve tendon-lengthing, tendon transfer, tenotomy (cutting the tendon) along with release of fibrotic joint contractures (ankle) or removal of tight fibrous bands (iliotibial band at lateral thigh from hip to knee)

15. Surgery: Middle Ambulatory Phase (3) • Single-level surgery (e.g. correction of ankle equinus deformity >20°) not indicated if there are knee flexion contractures of 10° or greater and quadriceps strength of grade 3/5 or less • Equinus foot deformity (toe-walking) and varus foot deformities (severe inversion) can be corrected by heel-cord lengthening and tibialis posterior tendon transfer through the interosseous membrane onto the dorsolateral aspect of the foot to change plantar flexion-inversion activity of the tibialis posterior to dorsiflexion-eversion. • Hamstring lengthening behind knee generally needed if knee-flexion contracture of more than 15° • After tendon lengthening and tendon transfer, post-operative bracing may be needed, which should be discussed pre-operatively. • Following tenotomy, bracing is always needed.

16. Surgery: Middle Ambulatory Phase (4) • When surgery performed to maintain walking, patient must be mobilised using a walker or crutches on the first or second postoperative day to prevent further disuse atrophy of lower-extremity muscles. • Post-surgery walking must continue throughout limb immobilisation and post-cast rehabilitation. • An experienced team with close coordination between the orthopaedic surgeon, physical therapist, and orthotist is required.

17. Surgery: Late ambulatory & early non-ambulatory phases • Late ambulatory • Generally ineffective • Obscures benefits of more timely interventions • Early non-ambulatory • Some clinics perform extensive lower-extremity surgery/bracing to regain ambulation within 3-6 months of loss of walking ability • This is generally ineffective: not currently considered appropriate

18. Surgery: Late non-ambulatory phase • Severe equinus foot deformities (>30°) can be corrected with heel-cord lengthening or tenotomy • Varus deformities (if present) can be corrected with tibialis posterior tendon transfer, lengthening, or tenotomy. • This is done for specific symptomatic problems • Generally to alleviate pain/pressure • Allow the patient to wear shoes • Correctly place the feet on wheelchair footrests. • This approach is not recommended as routine

19. Pain Management • Very little currently known about pain in DMD • Patients should be asked whether pain is a problem, so it can be addressed/treated • Appropriate intervention relies on determining cause of pain • Pain often results from posture problems and difficulty getting comfortable. Interventions can include • Provision of appropriate/individualised orthoses • Standard drug treatment approaches (muscle relaxants, anti-inflammatory medications) • Consider interactions with other medications (e.g. steroids, NSAIDS) and side-effects, especially those which might affect cardiac and respiratory function • Rarely, orthopaedic intervention may be indicated for pain that cannot be managed in any other way, but which might respond to surgery • Back pain, especially in steroid-treated patients, should prompt careful checking for vertebral fractures which respond well to bisphosphonate treatment.

20. References & Resources • The Diagnosis and Management of Duchenne Muscular Dystrophy, Bushby K et al, Lancet Neurology 2010 9 (1) 77-93 & Lancet Neurology 2010 9 (2) 177-189 • Particularly references, p186-188 • The Diagnosis and Management of Duchenne Muscular Dystrophy: A Guide for Families • TREAT-NMD website: www.treat-nmd.eu • CARE-NMD website: www.care-nmd.eu