Summary

A longitudinal observational study evaluating radiological parameters with validated patient reported outcome measures concluded Unicompartmental Knee Arthroplasty and Patellofemoral Joint Arthroplasty produces comparable outcomes to Total Knee Arthroplasty

Abstract

Introduction

Osteoarthritis (OA) is a progressive disease that often displays heterogeneous patterns of distribution across the three compartments of the knee joint. Total Knee Arthroplasty (TKA) replaces all compartments whilst Unicompartmental Knee Arthroplasty (UKA) and Patellofemoral Joint Arthroplasty (PFJA) are more joint preserving, targeting affected compartments only. The aim of this study was to compare the clinical and radiological outcomes of UKA vs PFJA vs TKA.

Methodology

A longitudinal observational study evaluating radiological parameters (including mechanical axis, hip-knee-ankle angle, joint line congruence, patellar tilt, Insall-Salvati ratio, joint space width, posterior tibial slope) and validated patient reported outcome measures (PROMs) pre- and post-operatively. This included Oxford knee score, Knee osteoarthritis outcome score (KOOS), Fulkerson score, Kujala score, EQ-5D and SF-12.

Results

A total of 129 patients were included (TKA n=72; UKA n=37; PFJA n=20). All procedures significantly improved radiological alignment (p<0.05) and PROMs (p<0.05) following surgery. Between-group analysis demonstrated all three groups achieved comparable post-operative PROM results, except for a superior overall KOOS score favouring TKA over PFJA (p<0.001) and also favouring UKA over PFJA (p<0.001). Overall, radiological measurements had a poor correlation with PROMs (p>0.05).

Conclusion

TKA, UKA and PFJA all demonstrated improved clinical outcomes and radiological alignment following surgery. Overall, clinical outcome was comparable between the three groups. Patient selection, modern implant designs and surgical technique are important in successful joint preserving arthroplasty.