Contrasts in gait mechanics of individuals with proximal femoral focal deficiency: Syme amputation versus Van Nes rotational osteotomy.

Lower-limb kinematics and kinetics during preferred and fast speeds of walking were measured in persons with proximal femoral focal deficiency to compare outcomes after Syme amputation (nine subjects) with those after Van Nes rotational osteotomy (10 subjects). Subjects with a Van Nes rotational osteotomy and full tibial rotation (seven subjects) demonstrated prosthetic knee function during stance as they were able to support a flexed-knee posture at both speeds and produced greater knee-extensor moments at preferred speeds as compared with the Syme group (p < 0.05). Nonprosthetic limb compensatory mechanics were significantly exacerbated in subjects with a Syme amputation compared with the Van Nes group: (a) stance-phase vaulting, resulting in greater inappropriate ankle-power generation at both walking speeds, (b) excessive hip-extensor moments at fast speeds, (c) excessive hip-power absorption and generation at both speeds, and (d) excessive knee-joint power generation at both speeds (p < 0.05). The improved gait after Van Nes rotational osteotomy is one factor that should be considered when making clinical decisions for children with proximal femoral focal deficiency.