Clinical Outcome Scores Post Medial Unicompartmental Knee Arthroplasty: A Comparison of the MAKO Robotic Arm versus the Oxford Conventional Approach

Abstract

Introduction: Unicompartmental knee arthroplasty (UKA) has significant advantages over total knee arthroplasty (TKA). However, due to its need for precise positioning and soft tissue balancing, UKA failures and revision rates may be higher than that of TKA. Robotic-assisted UKA offers more accurate implant positioning, soft tissue balancing, improved lower limb alignment, and a reduction in surgical error. There are few studies studying functional outcomes post robotic-assisted UKA. The aim of this study was to compare the functional outcomes between robotic-assisted and conventional medial UKA. Material and Methods: A retrospective review was done of 159 patients; 110 patients underwent conventional UKA while 49 patients underwent robotic-assisted UKA. Outcome measures included the Oxford Knee Score (OKS), Knee Society Score (KSS), Visual Analogue Score (VAS) for pain, and range of motion (ROM) at three months, one-year and two years post-UKA. Results: Pre-operative patient demographics and outcome scores were not significantly different between both groups. ROM was significantly greater in the MAKO compared to the Oxford group at 3 months (p=0.039), 1 year (0.053) and 2 years (0.001) post-operation. While OKS, KSS and VAS scores improved for both groups, there were no significant differences in the final outcome measures. None of the patients experienced a mechanical failure, infection, or revision post-surgery. One patient each in the Oxford and MAKO group suffered a periprosthetic fracture. Conclusion: Both robotic-assisted MAKO UKA and conventional Oxford UKA showed good clinical outcomes. Robotic-assisted MAKO UKA had superior ROM outcomes compared to conventional Oxford UKA up to two years post-surgery.