HAMSTRINGS IN CEREBRAL-PALSY CROUCH GAIT

After observing patients with increased anterior pelvic tilt following medial hamstring lengthening in cerebral palsy crouch gait, we became concerned that the hamstrings may be functionally important hip exten sors. To evaluate this, we studied the three-dimensional motion of the hip and knee, calculated hamstring muscle length, and evaluated dynam ic electromyography (EMG) of the medial hamstrings in 16 patients with diplegic cerebral palsy and crouch gait to determine if the hamstring s were extending the hip. Twelve of 16 patients exhibited marked prolo ngation of electrical activity in the medial hamstrings, and in eight of these 12, the hamstrings were contracting concentrically, thus aidi ng in hip extension during gait. Hamstrings may be important hip exten sors in some cerebral palsy patients with crouch gait; however, other deformities contributing to crouch (such as hip flexion contracture) n eed to be considered before isolated hamstring lengthening is performe d in these patients.