Outcomes of total knee replacement versus unicompartmental knee arthroplasty in an enhanced recovery after surgery protocol

Introduction

Unicompartmental Knee Arthroplasty (UKA) has become popular due to faster recovery and improved range of motion. However, concerns have been made regarding increased risk of early failure. Furthermore, the use of Enhanced Recovery After Surgery (ERAS) protocols have shown to allow faster return to activities, improved satisfaction, and reduced complication rates.

This study aims to compare the 6 month functional outcomes of patients undergoing Total Knee Replacement (TKR) versus UKA under the ERAS protocol.

Methods

Patient characteristics and comorbidities, 30-day post-operation readmission and infection rates were analyzed. Patient reported outcomes measures namely the Knee Society Function and Knee Score (KSFS, KSKS), Oxford Knee Score (OKS) and both the Physical and Mental component of the Short-Form Health Survey (SF-36) were assessed pre-operatively and 6 months post-operatively.

Univariate analysis was used to compare differences in characteristics and comorbidities between the 2 groups. Finally, a multiple linear regression was performed to compare the post-operative outcomes.

Results

Univariate analysis showed significantly better preoperative and 6 month post-operative KSKS and SF-36 MCS in UKA patients. Multivariate analysis showed no difference in the 6 month post-operative functional outcome scores between UKA and TKR patients. No UKA patients required revision surgery while 4 TKR patients required revision surgery for infection.

Conclusion

UKA achieves equivalent functional outcomes at 6 months post-operatively as compared to TKR patients and has lower infection rates. UKA is a reasonable option to offer for unicompartmental knee osteoarthritis patients.