PRELIMINARY RESULTS OF MINIMALLY INVASIVE UNI-COMPARTMENTAL KNEE ARTHROPLASTY USING A NEW PROSTHESIS

Abstract

Introduction and Aims: The aim of this study was to report the two-year results of a new tibio-femoral Uni-compartmental Knee Arthroplasty (UKA) designed specifically to be implanted through a minimally invasive approach.

Method: A prospective review of a single surgeon’s experience with the Preservation UKA was undertaken. The initial 54 UKAs from a consecutive cohort of 253 UKAs that had reached two-year follow-up were evaluated, clinically using the AKSS and OKS scores, and also radiographically. The average age of patients was 66.9 (range 48–82), with a slight male preponderance (1.2:1). Forty-five UKAs were for medial compartment OA (40 all polyethylene fixed tibial bearing, five mobile bearing), with eight bilateral procedures, and nine were for lateral compartment OA (seven all polyethylene fixed tibial bearing, two mobile bearing).

Results: There were no losses to follow-up. The pre-operative AKSS knee and function scores improved from 39 and 56 respectively, to 93 (range 46–100) and 92 (range 10–100) respectively, at last review. The OKS had improved from 39 to 19 (range 12–40), and the average range of motion was 135 degrees (range 125–140). There were no failures requiring revision. Only two patients had poor results, one secondary to a post-operative work related injury and the other due to soft tissue impingement that responded to arthroscopic debridement. One patient was excluded due to a femoral neck fracture. One patient experienced a superficial wound infection, and one patient had a pulmonary embolus. Radiographs revealed minor tibial lucencies in three UKAs, none of which were symptomatic, or progressive to date.

Conclusion: This is the first report documenting two-year results of this new prosthesis, and preliminary results suggest it can produce good clinical and functional results.