Unicompartmental vs. total knee replacement in patients with failed high tibial osteotomy.

INTRODUCTION

The influence of a previous high tibial osteotomy (HTO) on the outcome and survival of a knee arthroplasty is a debated issue. The purpose of this study is to compare subjective, radiographic, and functional outcomes of unicompartmental knee replacement (UKR) and total knee replacement (TKR) after failed open wedge HTO.

METHODS

26 post-HTO UKRs (group A) with an average follow-up of 7.8 years (range 2-13), and 33 post-HTO TKRs (group B) with an average follow-up of 11.2 years (range 4-16) operated between 2001 and 2017, were retrospectively reviewed. Assessment included Knee Society Score (KSS), University of California at Los Angeles Activity Score (UCLA), and Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Standard knee X-rays, and long-standing X-rays were performed pre-operatively and at follow-up to evaluate prosthesis survival, coronal alignment, and patellar height.

RESULTS

Improvements regarding KSS, UCLA and WOMAC scores were noted at follow-up in both groups compared to pre-operatory status (p < 0.001). No statistically significant differences in clinical and functional postoperative scores were reported between groups (p = n.s.) at follow-up. Group B presented a more neutral mean mechanical axis of 0.5° compared to 2.7° in Group A (p < 0.001).

CONCLUSIONS

Performing UKR after previous failed HTO is a safe and effective procedure which leads to clinical, radiological and functional outcomes comparable to TKR after HTO.