Diminished knee flexion after hamstring surgery in cerebral palsy patients: prevalence and severity.

A review of pre- and postoperative prone knee flexion (PKF) data after isolated hamstring tenotomy for 52 patients with cerebral palsy (CP) at an average follow-up of 3 years 4 months showed the frequency of diminished knee flexion to be 71%. Twenty-three percent of the knees actually had improved flexion, whereas 6% were unchanged. On the average, patients' flexion decreased 14.4 degrees from a preoperative PKF of 131.5 degrees to 117.1 degrees postoperatively (p < 0.0001). Only 11.5% of patients had PKF < 90 degrees at most recent follow-up, however; only 1.9% had PKF < 60 degrees. Thirteen percent of ambulators eventually required a rectus femoris transfer to correct "stiff-legged gait."