Can clinical foot and ankle assessments improve the prediction of patient reported outcomes in knee arthroplasty?

Abstract

Knee arthroplasty (KA) has been considered to be a successful and cost-effective intervention for individuals with severe end stage Osteoarthritis (OA). A number of clinically important predictors of outcomes following KA have been established, however there are still other factors to be identified to improve our ability to recognise patients at risk of poor KA outcomes. Although the relationship between foot, ankle and knee kinematics has become widely accepted, it is not known whether foot and ankle status affect KA outcomes. This thesis therefore aims to determine whether clinical foot and ankle measures are useful in predicting patient reported outcomes following KA. A formal literature review was firstly undertaken to identify current methods of assessing musculoskeletal foot and ankle status. Findings of the review revealed an absence of a standardised assessment protocol and a lack of agreement and validity for many current clinical measures. In response to this an international expert consensus study was undertaken to produce an agreed set of objective clinical musculoskeletal foot and ankle assessment measures to form a new protocol. Two measures identified from the review, and agreed via expert consensus, as the most robust assessment methods- the Foot Posture Index (FPI) and ankle dorsiflexion, were introduced to a large prospective cohort of patients awaiting knee arthroplasty, in addition to foot pain questions. Results show that ankle dorsiflexion and foot posture were not associated with one year knee outcomes, however pre-operative foot pain was associated to outcome; the presence of foot pain increased the risk of a poor post-operative clinical outcome. Findings suggest that it would be beneficial to address foot pain prior to surgery to reduce the risks associated with a poor outcome. Further work would be beneficial to establish the sequential link between foot pain and knee OA in order to inform the most appropriate method of the conservative management.