Kinetic and kinematic characteristics of gait in patients with medial knee arthrosis.

We compared the mechanics of gait in 13 patients with early medial arthrosis (OA) of the knee and 13 normal controls, by measuring gait events, kinematic and kinetic parameters. In the OA group, walking velocity, cadence and stride length were reduced and stride time and double support time accordingly increased on both sides, the overall stance phase was prolonged in the OA group, but the stance phase and swing phase peak flexion were reduced. The varus in the stance phase and the valgus in the swing phase were increased. The extensor moment in the loading response was increased and the flexor moment at late stance reduced in the OA group. Patients with OA had a greater valgus (abductor) and internal rotation moment during the stance phase. The times to second vertical force peak (VFP) were similar in the two groups. Values of VFP1 and VFP2 were lower in the OA group. Our findings indicate that computerized gait analysis can be used to reveal various mechanical abnormalities accompanying arthrosis of the knee joint at an early stage. Some of these abnormalities may have etiologic implications, but others may represent secondary changes developed in part as a compensatory mechanism in knee OA.