Abstract
Introduction
With the introduction of minimally invasive surgery techniques and improved polyethylene wear properties, there has been a renewed interest in Unicondylar Knee Replacements (UKR). Customized, Individually Made (CIM) UKR have been in the market for some time, and have shown to provide improved coverage and fit. The purpose of this study was to assess clinical and patient-reported outcomes utilizing CIM-UKR prostheses.
Methods
A prospectively recruited cohort of 118 patients was implanted with 120 CIM-UKR (110 medial/10 lateral) at multiple centers across the US. Patients were diagnosed with uni-compartmental osteoarthritis of the medial or lateral compartment. Patients with compromised cruciate or collateral ligaments or having a varus/valgus deformity <15° were excluded. Patients were assessed for Knee Society Knee and Function Scores, WOMAC & ROM pre-operatively (120 patients), at 6-weeks post-op (119), 6-months post-op (71 optional visit), 1 year post-op (113) and 2 years post-operatively (96). For the 3 and 4 year post-operative time points, patients were contacted to report on any possible adverse events.
Results
Range-of-motion was improved from 120° pre-operatively to 131° at 2 years post-op. Patients demonstrated marked improvements from baseline scores across all domains. All patients have passed their 2-year follow up visit to date. Average KSS Knee Scores significantly improved from their preoperative levels to 95 at the 2-years follow-up visit. KSS Function domain scores significantly improved from pre-operative levels to 91 at the 2 year time-point. Similar improvements were noted in the WOMAC score, which was reported to be 89 at the 2 year time point. Average VAS Pain scores at the 2 year visit was 1.3. To date, at an average follow-up of 3.1 years there have been 2 patients revised for tibial loosening and an additional 2 patients have been revised for disease progression in the other compartments of the knee.
Discussion
There are a multitude of studies of off-the-shelf mobile and fixed-bearing UKR. The 2-year follow up data collected on CIM-UKR compares favorably to both published scores as well as revision rates for off-the-shelf implants.
