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

N Van Egmond,N L W Keijsers,A Van Kampen,R Van Heerwaarden,N Stolwijk

doi:10.1007/s00167-016-4045-x

Abstract

PurposeIn 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.MethodsTwelve patients and ten healthy controls were included. Both kinetics and kinematics of gait and clinical and radiographic outcomes were evaluated.ResultsThe 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°).ConclusionIn 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 evidenceIII.

Highlights

Malalignment of the leg increases the risk of progression of knee osteoarthritis (OA) and causes a decline in physical function and progression of pain [15, 32]
A significant increase in the knee adduction moment during stance phase was found, which was related to the degree of correction
The hip knee ankle (HKA) angle towards zero degrees caused a medial shift in the dynamic knee loading

Summary

Introduction

Malalignment of the leg increases the risk of progression of knee osteoarthritis (OA) and causes a decline in physical function and progression of pain [15, 32]. One of the possible reasons for this increased risk of OA is that a malalignment of the knee influences the forces and moments acting on the knee during walking. Kaufman et al [17] found a significant difference between patients with knee OA (0.39 % BW–HT, SD 0.28) and healthy subjects (0.36 % BW–HT, SD 0.36). Turcot et al [35] found a significant difference between patients with a varus leg alignment (0.62 Nm/kg, SD 0.19) compared to the control group (0.50 Nm/kg, SD 0.12). The literature has shown a relationship between the degree of knee deformity and the forces acting on the knee [32, 33, 35, 36, 39, 40]

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