Background: Progressive crouch gait occurs in patients with cerebral palsy with increasing age. Hamstring lengthening improves crouch in these patients, but hamstring contractures can recur over time. The purpose of this study was to determine whether revision hamstring lengthening is as effective as primary lengthening in improving crouched gait.
Methods: Retrospective review was performed for 39 patients with static encephalopathy, average age 10±4 years, who underwent hamstring lengthening. Twenty-one subjects underwent a single hamstring lengthening (HSL group), and 18 underwent repeat HSL (rHSL group). Range of motion (ROM) and kinematic measures from preoperative and postoperative gait analysis testing were compared within and between groups using t tests, χ2 tests, and multiple regression analyses as appropriate.
Results: A total of 15/21 subjects in the HSL group (71%) improved stance knee extension by ≥10 degrees, as compared with 5/18 (28%) in the rHSL group (P=0.007). The HSL group had improved popliteal angle, static knee and hip extension ROM, and knee flexion at initial contact and in stance phase (P<0.003). No such improvements were seen in the rHSL group. Popliteal angle, knee and hip extension ROM, and knee flexion at initial contact and in stance phase had significantly greater improvement in the HSL than the rHSL group (P<0.01). These differences persisted after adjusting for preoperative minimum hip flexion in stance, the only variable that differed between groups preoperatively.
Conclusions: Repeat hamstring lengthening may delay progressive crouch, but does not result in long-term correction of crouch gait. Recurrent crouch may be caused by other factors such as quadriceps insufficiency, and may reflect the natural history of CP. Patients with recurrent crouch after hamstring lengthening are likely to benefit more from alternative surgical interventions to improve their knee position and function during gait.
Level of evidence: Level IV-case series.