Bridging the Gap: The Influence of Foot and Ankle Pathomechanics in Total Knee Arthroplasty

Abstract

Altered spinopelvic mechanics can have dramatic influences on the success of hip arthroplasty as seen with concomitant hip and spine disease. Interestingly, limited focus has been directed toward a similar codependent relationship between concurrent knee and foot deformities. By bridging this interdisciplinary gap, we attempt to explore the current understanding and clinical implications of concomitant knee and foot pathology while reviewing management options for addressing this unique yet ubiquitous patient population. Multiple authors have demonstrated an inverse relationship between progressive coronal plane deformities concerning the knee and hindfoot. The utility of a conventional mechanical axis during total knee arthroplasty may be limited in the presence of foot deformity where ground reactive forces often markedly deviate with the hindfoot, potentially leading to eccentric knee loading. The use of alternative indices, such as ground mechanical axis deviation, may offer a more reliable metric for achieving an accurate neutral mechanical axis. In addition, although foot deformity and compensation can often improve to a limited degree after total knee arthroplasty, residual deformity may have deleterious effects on the success of the procedure. A comprehensive understanding of the functional relationship between the foot and the knee can allow surgeons to better guide appropriate treatment sequence, often beginning with the more symptomatic deformity. Future research is needed to further elucidate the implications and appropriate management of concomitant knee and foot deformity.