Introduction

We report 10-year clinical outcomes of a prospective randomised controlled study on uni-compartmental knee arthroplasty using an active constraint robot.

Measuring the clinical impact of CAOS systems has generally been based around surrogate radiological measures with currently few long-term functional follow-up studies reported. We present 10 year clinical follow up results of robotic vs conventional surgery in UKA.

Introduction: Unicompartmental knee Arthroplasty (UKA) is a commonly used and accepted treatment for Osteoarthritis (OA) in the medial compartment. How-ever, despite some good results¹ there is still a reluctance to use this procedure in the lateral compartment for the same indications, as the procedure is considered technically difficult, and not as successful². This study reports the clinical outcome of lateral UKAs in comparison with medial UKAs, TKAs and a normal population group using a knee score designed to highlight the shortcomings of TKA³.

Methods: 20 consecutive patients over 2 years following lateral UKA were functionally assessed. They were compared with 3 groups of 20 age and sex matched patients: those who had undergone medial UKA or TKA in the same time period, or normal controls from an upper limb clinic. Clinical function was assessed at least 2 years postoperatively, using the ‘total knee questionaire’³. This consists of 55 scaled multiple choice questions. The score is derived from the product of three scales: the importance of a specific activity, the frequency with which it is undertaken, and the ease with a patient can perform it.

Results: 90% of the patients reported that they were either satisfied or very satisfied with their lateral UKA, with 95% of the patients in the medial UKA group and 75% in the TKA group reaching this level of satisfaction. The average Composite Score for the lateral UKA group was significantly better compared with the TKA group (p < 0, 05). (Kneeling – (5,72/4,45), Gardening – (7,32/5,18), Pivoting – (7,83/6,78) and Walking with heavy bags (8,2/5,97)). The Total Composite Score was significantly better (p< 0, 05) in Patients after lateral UKA (7,14) compared to patients who underwent TKA (5,99). No statistically significant differences in the Total Composite Score was found between both the lateral & medial UKA patients taken as a single group compared with the control group.

Conclusion: Lateral Unicompartmental Knee Arthroplasty achieves superior knee function in comparison to Total Knee Arthroplasty, so is worth considering as an option in for early OA of the lateral compartment.