Summary

Regardless of the type of prosthesis performed, osteoarthritis patients showed better function and satisfaction about activities after knee arthroplasty when operated for anteromedial osteoarthritis compared to other or more severe wear patterns.

Abstract

Introduction

A knee arthroplasty (KA) is a well-accepted and suitable surgical procedure for osteoarthritis (OA) patients to relieve pain, return to function and to improve health-related quality of life. Unfortunately, patients after knee arthroplasty are often not satisfied, especially not about their activity levels. We aimed to determine if the wear pattern of knee OA or type of prosthesis affects knee-specific function scores and satisfaction levels about activities.

Methods

A cross-sectional observational study was performed. Based on radiological assessment of anteromedial osteoarthritis (AMOA) and type of KA, total knee arthroplasty (TKA) or Unicondylar Arthroplasty (UKA), patients were divided into three groups: True TKA (N=99), TKA for AMOA (N=68) and UKA (N=100). Knee injury and Osteoarthritis Outcomes Score (KOOS), New Knee Society Score (New KSS), Anterior Knee Pain Scale (AKPS), and Visual Analogue Scales (VAS) for satisfaction about activities were collected.

Results

After mean follow-up of 2 years both KOOS, 2 of 4 subgroups of New KSS, AKPS, and all VAS satisfaction scales showed significant better outcome of TKA for AMOA and UKA compared to the True TKA group. In the AMOA patients, similar results were found between the TKA and UKA. Age, sex and BMI did not affect these results.

Conclusion

The present study demonstrated superior outcomes in knee-specific function scores, overall satisfaction and satisfaction related to activities after KA for AMOA, compared to more advanced OA and other wear patterns, and this was more likely to be the case if patients with AMOA were treated with a UKA. In line with previous studies, it might be worth considering to proceed with knee replacement in an earlier stage, i.e. before deterioration of the functional status sets in, to get the best results and thus most satisfied patients after KA. Thinking of known advantages of UKA to the patient, we believe that these results confirm UKA as a good alternative for TKA in treating AMOA. The radiologic assessment of wear patterns is important and can be useful in the shared decision-making process, when discussing expectations, timing, and outcomes with OA patients considering KA.