Paralytic deformities of the lower limb.

Deformity may occur in any paralytic condition in childhood. It develops after birth in poliomyelitis, cerebral palsy, hereditary neuropathies and muscular dystrophies or before birth in spina bifida, spinal agenesis and arthrogryposis. Paralytic deformities arise primarily in muscles and their tendons, and are due to diminished musculo-tendinous growth associated with unbalanced muscle action. Their inexorable progress is only controlled effectively by surgical correction of tendon length and muscle imbalance. The paralysis needs to be assessed according to the specific type of paralytic lesion, and surgical treatment applied with due reference to ultimate function in adult life.