Prediction of outcome after rectus femoris surgery in cerebral palsy: The role of cocontraction of the rectus femoris and vastus lateralis

Rectus femoris surgery was performed on 70 patients with cerebral palsy and stiff-knee gait. Fifty-three patients underwent distal rectus transfer, an d 17 patients had distal rectus release with complete muscle mobilization. Gait analysis was performed preoperatively and postoperatively at a minimum of 1 year. Swing-phase peak knee flexion (PKF) was improved in the transfe r group, allowing improved foot clearance and more efficient gait (p = 0.03 ). PKF in swing deteriorated slightly in the release group (p = 0.03). The presence of abnormal swing-phase electromyogram (EMG) activity in the rectu s alone or abnormal combined rectus and vastus lateralis activity did not i nfluence the PKF results in either surgery (p > 0.05). The fly test had no predictive value in identifying patients with abnormal EMG activity (p > 0. 05). Preoperative knee range of motion was not a significant variable in de termining relative success of rectus surgery. No deleterious effects were o bserved in stance phase in either group (p > 0.05).