Distal Rectus Femoris Intramuscular Lengthening for the Correction of Stiff-Knee Gait in Children With Cerebral Palsy

Abstract

To evaluate the effects of rectus femoris intramuscular lengthening, a novel procedure to treat stiff-knee gait in ambulatory patients with cerebral palsy, using preoperative and postoperative 3-dimensional gait analysis. This study was a retrospective data review of ambulatory patients with a diagnosis of cerebral palsy who had undergone rectus femoris intramuscular lengthening. The indications for rectus femoris intramuscular lengthening were identical to those of rectus femoris transfer. Patients must have had preoperative and postoperative gait analyses at our institution. Three-dimensional kinematic and kinetic data was collected using a VICON 512 motion measurement system (VICON Motion Systems, Inc, Lake Forest, CA) after standard techniques. A representative trial was selected for analysis both preoperatively and postoperatively. Preoperative to postoperative differences were measured using a Student t test (P < 0.05). Selected sagittal plane kinematic and kinetic parameters were analyzed. A total of 42 patients (69 sides) treated between 1991 and 2008 with preoperative and postoperative gait analyses after rectus femoris intramuscular lengthening were analyzed. The mean age at surgery was 8.5 years (SD ± 2.9) and the mean time after surgery at postoperative gait analysis was 17.9 months (range, 7 to 53 mo). There were 26 male and 16 female patients. Compared with preoperative values, postoperative gait analysis revealed patients to have earlier timing of peak knee flexion in swing (82%→80% of gait cycle, P = 0.001), less crouch (average knee flexion in stance 26→20 degrees, P = 0.002), and maintenance (no statistically significant difference) of peak knee flexion. A cohort of patients also showed maintenance of knee function at intermediate-term follow-up (mean 44.6 mo). Patients who underwent soft-tissue surgery only benefited more from the procedure than those who also underwent bony surgery. Rectus femoris intramuscular lengthening may offer an alternative procedure for the treatment of stiff-knee gait in ambulatory patients with cerebral palsy. When comparing preoperative and postoperative gait analysis data, our cohort showed maintenance of peak knee flexion in swing, earlier timing of peak knee flexion in swing, and less crouch. Patients who underwent soft-tissue surgery only showed the most benefit. Level IV.