Optimal gait retraining strategies in patients with knee osteoarthritis

Abstract

Main topics: Rehabilitation; Experimental studies in human movement science Introduction and aim: Progression of knee osteoarthritis (OA) seems related to a high external knee adduction moment (EKAM) during gait [1,2], which can be reduced by gait retraining [3]. In healthy adults, lateral trunk lean and medializing the knee during gait reduce the EKAM effectively, although the optimal strategy seems individually dependent [3]. We aimed to determine which strategy reduces the EKAM most in patients with knee OA, and if the same strategy is most effective for all patients. Patients/materials and methods: Twenty-eight patients with radiographically diagnosed medial tibio-femoral knee OA underwent 3D gait analysis. Comfortable walking, lateral trunk lean towards the affected leg during the stance phase (Trunk Lean), and medializing the knee at initial contact (Medial Thrust) were investigated. Knee moments and kinematics of the knee and the trunk were calculated. Gait retraining strategies were assessed by comparison of EKAMpeak and impulse relative to comfortablewalking. Results: Most patients (age: 60.1±6.1 years, height: 1.71±0.10m, weight: 77.9±12.7 kg, mean KOOS-score: 46.3, KOOS subscales: pain (55.5), symptoms (52.5), daily activities (60.8), sport/recreation (26.8), knee-related QoL (36)) could finish the protocol without reporting any difficulties. One patient could not perform Medial Thrust due to knee pain. Fig. 1 shows the EKAM for all conditions. In both retraining strategies, EKAM was reduced significantly for early stance peak (MT: −0.07±0.01Nm/Bw·Ht, TL: −0.08±0.01Nm/Bw·Ht) and impulse (MT: −0.18±0.01Nms/Bw·Ht, TL: −0.03±0.01Nms/Bw·Ht). In 15 patients, Trunk Lean reduced overall EKAM peak the most (−0.09±0.04Nm/Bw·Ht). In 12 patients this was true for Medial Thrust (−0.13±0.07Nm/Bw·Ht). In the Medial Thrust group, leaning the trunk was significantly less effective than medializing the knee (p=0.005). In the Trunk Lean group, medializing the knee was significantly less effective than leaning the trunk (p=0.001). Changes in trunk angle and knee adduction angle as a result of retraining were similar between the groups (p>0.288). Discussion and conclusions: Medial Thrust and Trunk Lean effectively reduce the early stance EKAM peak and impulse during gait in patients with medial tibio-femoral knee OA. Even if the gait retraining instructions are not executed differently, the effectiveness of gait retraining strategies in reducing peak EKAM depends Fig. 1. EKAM for all conditions. Grey areas represent 95% CI for Normal Walking.