Summary

A systematic review into the proximal and distal joint alignment and gait in varus knee deformity in the younger arthritic patient demonstrates an inverse compensatory relationship in the hindfoot which reverts following high tibial osteotomy and may impact perioperative planning.

Abstract

Background

Varus deformity is common in medial compartment knee osteoarthritis (OA). This coronal malalignment is compensated for by static and dynamic adjustments in the position of the adjacent joints, principally in the hindfoot & ankle. This condition can be treated in selected patients by high tibial osteotomy (HTO), stabilised with a fixed angle plate plate or circular frame, which may reverse these changes. The aim of this systematic review is to determine the evidence available for these compensatory mechanisms with the objectives being to improve deformity planning and optimise patient outcomes. Method: A systematic review with meta-analysis was designed using the PRISMA template to meet the research aim & objectives. Results: A total of 1,006 patients (1,020 knees), combined mean age 54.5 years, female:male ratio of 0.9:1, were extracted from 20 included studies. The methodologies of the majority of studies were at high risk of bias on the Newcastle-Ottawa Scale demonstrating significant heterogeneity. The combined mean change in the HKA axis was 7.7°; MPTA 7.4°; TT, 0.21°; TI 4.56° & AJLO 4° valgus. Conversely, preoperative hindfoot valgus compensation reverts towards neutral post-HTO. There is limited evidence available for a direct relationship between alignment and gait parameters. Conclusions: An inverse relationship between ankle and hindfoot alignment in varus deformity of the knee forms the basis of this compensation theory. In cases with significant hindfoot compensation, the reconstructive orthopaedic surgeon may consider angulation-translation HTO rather than the standard angulation-only approach, in order to optimise alignment.