One hundred and forty-four boys who had Duchenne muscular dystrophy were managed at a single center between 1953 and 1994 and were followed for a mean of 8.9 years. The long duration of follow-up provided an opportunity to examine the effects of physical therapy and orthopaedic treatment on contractures of the lower extremities and on the duration of the ability to walk. Contractures of the lower extremities were controlled best when patients were managed with a combination of daily passive stretching exercises, prescribed periods of standing and walking, tenotomy of the Achilles tendon, posterior tibial-tendon transfer, and application of knee-ankle-foot orthoses. Approximately two years after bracing, the severity of the contracture of the heel cords was similar in the patients who had had an operation and those who had not. By the fourth year after bracing, however, the patients who had had an operation had less severe contractures than those who had had bracing alone. Five to seven years after the operation and bracing, control of contractures was still good, especially for the patients who had had posterior tibial-tendon transfer. Contracture of the knee was well controlled five to seven years after bracing in all patients who had had bracing, with or without an operation. The program enabled the patients who had been managed with bracing to walk until a mean age of 13.6 years. After loss of the ability to walk with bracing, the ability to stand continued for an additional two years with use of orthoses. The findings of the present study demonstrate the value of traditional methods of operative treatment and bracing for controlling contractures of the lower extremities in patients who have Duchenne muscular dystrophy and for prolonging their ability to walk.