Long‐term muscle changes after hamstring lengthening in children with bilateral cerebral palsy

Aim To evaluate short‐term (1y postoperatively; E1) and long‐term (at least 4y postoperatively; E2) changes in hamstring muscle‐tendon length (MTL) and lengthening velocity after hamstring lengthening in children with bilateral cerebral palsy (CP). Method Three‐dimensional gait analysis was performed in 19 children (16 males, 3 females; 36 limbs; mean age at surgery 9y [SD 3y]; range 6–10y) with flexed knee gait, preoperative ankle dorsiflexion lower than 20 degrees, and CP before bilateral hamstring lengthening (E0), at E1 and E2. Hamstring MTL (normalized by leg length) and velocity were assessed via OpenSim software. Results MTL increased from E0 to E1 (p=0.004) and decreased from E1 to E2 (p