To assess long and short term kinematic gait outcomes after rectus femoris transfers (RFT) in ambulatory children with cerebral palsy (CP).

A retrospective review was conducted of ambulatory children with spastic diplegic CP, who had RFT plus motion analysis preoperatively and 1 year post-operatively. Those with 5 and 10 year post-operative motion analysis were also included. The primary variables were: peak knee flexion range of motion in swing (PKFSW), timing of peak knee flexion in swing as a percent of the gait cycle (PKF%GC), and knee range of motion from peak to terminal swing (KROM). Responders and non-responders were identified. Descriptive, kinematic and kinetic variables were evaluated as predictors of response.

119 ambulatory children (237 limbs) with spastic diplegic CP who had RFT were included. Mean age at surgery was 10.2 years (range 5.5 to 17.5). Sixty-seven participants were classified at GMFCS Level II and 52 at GMFCS Level III. All participants (237 limbs) had a preoperative and 1 year postoperative motion analysis. Motion analysis at 5 and 10 years post-operatively included 82 limbs and 28 limbs, respectively. Ninety-three (39%) limbs improved in both PKFSW and PKF%GC. PKFSW improved in 59% of limbs. Responders started 1.2 SD below the mean PKFSW preoperatively, and improved by an average of 1.9 SD to reach a normal range at 1 year post-operatively (p < 0.05). Improvement was maintained at 5 and 10 years postoperatively. Those at GMFCS level II were more likely [OR 1.71, CI 1.02, 2.89] to have improved PKFSW at 1 year postoperatively than those at GMFCS level III. PKF%GC improved in 70% of limbs. Responders had delayed PKF%GC, starting 10 SD above the mean (later in the gait cycle) preoperatively. Their timing improved towards normal values: 5 SD, 5.9 SD, 3.5 SD from the mean, (earlier in the gait cycle) at 1, 5 and 10 years postoperatively, respectively (p<0.05). KROM improved in only 24% of limbs. For all variables, there was a significant difference in mean preoperative values between responders and non-responders (p<0.05).

RFT improves short and long-term kinematic gait outcomes. The majority of children responded to RFT with improvements in PKFSW or PKF%GC at 1, 5, and 10 years post RFT. GMFCS level is a predictor of improved PKFSW, with children at GMFCS Level II having an increased likelihood of improvement at 1 year post surgery. Children who have worse preoperative values of PKFSW, PKF%GC, and KROM have a greater potential for benefit from RFT. Characteristics associated with responders who maintain long term positive outcomes need to be identified.