Gait analysis before and after corrective osteotomy in patients with knee osteoarthritis and a valgus deformity

Abstract

Purpose: In this prospective study, the changes in kinetics and kinematics of gait and clinical outcomes after a varus osteotomy (tibial, femoral or double osteotomy) in patients with osteoarthritis (OA) of the knee and a valgus leg alignment were analysed and compared to healthy subjects.

Methods: Twelve patients and ten healthy controls were included. Both kinetics and kinematics of gait and clinical and radiographic outcomes were evaluated.

Results: The knee adduction moment increased significantly postoperatively (p < 0.05) and almost similar to the control group. Patients showed less knee and hip flexion/extension motion and moment during gait pre- and postoperatively compared to the controls. A significant improvement was found in WOMAC [80.8 (SD 16.1), p = 0.000], KOS [74.9 (SD 14.7), p = 0.018], OKS [21.2 (SD 7.5), p = 0.000] and VAS-pain [32.9 (SD 20.9), p = 0.003] in all patients irrespective of the osteotomy technique used. The radiographic measurements showed a mean hip knee ankle (HKA) angle correction of 10.4° (95 % CI 6.4°-14.4°).

Conclusion: In patients with knee OA combined with a valgus leg alignment, the varus-producing osteotomy is a successful treatment. Postoperatively, the patients showed kinetics and kinematics of gait similar as that of a healthy control group. A significant increase in the knee adduction moment during stance phase was found, which was related to the degree of correction. The HKA angle towards zero degrees caused a medial shift in the dynamic knee loading. The medial shift will optimally restore cartilage loading forces and knee ligament balance and reduces progression of OA or the risk of OA. A significant improvement in all clinical outcomes was also found.

Level of evidence: III.

Keywords: Closed wedge medial high tibial osteotomy; Double osteotomy; Gait analysis; Supracondylar femoral osteotomy; Valgus alignment.

Fig. 1

Rationale of double osteotomy in valgus corrective surgery. Weight-bearing long-leg radiographs and planning drawings including weight-bearing lines (WBL) and knee joint orientation lines (KJOL) of one of the study patients. a Preoperative valgus leg alignment caused by femoral and tibial bone deformity, WBL lateral and KJOL neutral. b Planning drawing of medial closing wedge distal femur osteotomy resulting in neutral WBL and severe valgus KJOL. c Planning drawing of double osteotomy, i.e. lateral open wedge distal femur and medial closing proximal tibial osteotomy, resulting in neutral WBL and neutral KJOL. d Postoperative leg alignment after double osteotomy

Fig. 2

Knee valgus/varus and flexion/extension angles. Upper panels the knee angles of the controls, preoperative condition and postoperative condition for the valgus/varus (left panel) and flexion/extension (right panel) angle. Dark areas in the bars right above the x-axis indicate significant differences (p < 0.05) between: &, postoperative and controls; #, preoperative and controls; $, pre- and postoperative. Lower panels knee varus/valgus and flexion/extension angles for the DOT, SCO and TKO group. Pre- and postoperative as well as the control data are displayed. HS heel strike, TS toe strike, HO heel off, OH opposite heel strike, TO toe-off, Deg degrees, Pre preoperative, Post postoperative, DOT double osteotomy, SCO supracondylar osteotomy, TKO high tibial osteotomy

Fig. 3

Hip abduction/adduction and flexion/extension angles. Upper panels the hip angles of the controls, preoperative condition and postoperative condition for the abduction/adduction (left panel) and flexion/extension (right panel) angle. Dark areas in the bars right above the x-axis indicate significant differences (p < 0.05) between: &, postoperative and controls, #, preoperative and controls, $, pre- and postoperative. Lower panels hip abduction/adduction and flexion/extension angles for the DOT, SCO and TKO group. Pre- and postoperative as well as the control data are displayed. HS heel strike, TS toe strike, HO heel off, OH opposite heel strike, TO toe-off, Deg degrees, Pre preoperative, Post postoperative, DOT double osteotomy, SCO supracondylar osteotomy, TKO high tibial osteotomy

Fig. 4

Knee external knee abduction/adduction and flexion/extension moments. Upper panels the knee moments of the controls, preoperative condition and postoperative condition for the abduction/adduction (left panel) and flexion/extension (right panel) moment. Dark areas in the bars right above the x-axis indicate significant differences (p < 0.05) between: &, postoperative and controls, #, preoperative and controls, $, pre- and postoperative. Lower panels knee abduction/adduction and flexion/extension moments for the DOT, SCO and TKO group and the controls. HS heel strike, TS toe strike, HO heel off, OH opposite heel strike, TO toe-off, Deg degrees, Pre preoperative, Post postoperative, DOT double osteotomy, SCO supracondylar osteotomy, TKO high tibial osteotomy

Fig. 5

Hip abduction/adduction and flexion/extension moments. Upper panels the hip moments of the controls, preoperative condition and postoperative condition for the abduction/adduction (left panel) and flexion/extension (right panel) moment. Dark areas in the bars right above the x-axis indicate significant differences (p < 0.05) between: &, postoperative and controls, #, preoperative and controls, $, pre,- and postoperative. Lower panels hip abduction/adduction and flexion/extension moments for the DOT, SCO and TKO group and controls. HS heel strike, TS toe strike, HO heel off, OH opposite heel strike, TO toe-off, Deg degrees, Pre preoperative, Post postoperative, DOT double osteotomy, SCO supracondylar osteotomy, TKO high tibial osteotomy