Changes in Sagittal Plane Kinematics and Kinetics after Distal Release of Medial Hamstrings in Cerebral Palsy

Abstract

The purpose of this study is to analyze the effect of distal release of the medial hamstrings on the gait of patients who had spastic cerebral palsy. Twenty-two patients had preoperative and postoperative gait analysis. Standard parameters, such as cadence, velocity, and stride length, were evaluated, as were sagittal plane motion graphs of the pelvis, hip, knee, and ankle, in addition to sagittal plane kinetic analysis. Extension of the knee in stance phase significantly improved postoperatively (p < 0.002), and the improvement was accompanied by a proportional decrease in knee flexion during swing with minimal net gain in the arc of knee motion. Knee range of motion could be improved more by concomitant rectus transfer in selected patients. The statistically significant increase in anterior pelvic tilt (p < 0.002) has been a main concern. There was no significant change in the hip extensor moments or power generation during stance. Increased knee extension during stance after distal release of medial hamstrings is the kinematic gain that improved the gait pattern in cerebral palsy patients. The authors recommend a concomitant rectus transfer to help improve the knee range of motion in patients with rectus over-firing during swing, hence avoiding a stiff knee gait.

Correction of Combined Flexed and Stiff Knee Gait in Spastic Diplegic Cerebral Palsy by Double Tendon Transfers around the Knee as Part of Multilevel Surgery

“…20 A recent study has shown that simple hamstring lengthening will significantly decrease hip extension in stance phase, but interestingly, hip extension power was not affected. 21 Semitendinosus transfer to the adductor tubercle is advocated to preserve hip extension during stance phase. A study comparing hamstring lengthening and transfer showed improvement in extension power with preservation of hip extension range in the group of hamstring transfer.…”