Abstract
INTRODUCTION
Unicompartmental knee arthroplasty (UKA) allows replacement of a single compartment in patients who have isolated osteoarthritis as a minimally invasive procedure. However, limited visualization of the surgical site provides challenges in ensuring accurate alignment and placement of the prosthesis.
With robot-assisted surgery, correct implant positioning and ligament balancing are obtainable with increased accuracy. To date, there has not been a large series reported in the literature of UKAs performed with robotic assistance. The aim of this study was to examine the clinical outcomes of robot-assisted UKA patients.
METHODS
510 patients who underwent robotic-assisted UKA between July 2008 and June 2010 were identified (average age 63.7 years, range: 22 to 28 years). Clinical outcomes were evaluated using the Oxford Knee Score (OKS) and patients without recent follow-up were phoned. Revision rate and time to revision were also examined.
RESULTS
Average length of stay was 1.4 days (range: 1 to 7 days). There was minimal blood loss with most procedures. There were two intra-operative complications, both in early patients in the series. The first intra-operative complication was broken alignment pins in both the femur and tibia. In the second complication, preparation was finished manually with a burr due to registration problems with the software. Both patients were doing well at most recent follow up and neither experienced further complications.
At latest clinical follow-up, patients reported a mean OKS of 36.1 + 9.92. The revision rate was 2.5% with 13 patients either converted from an inlay to onlay prosthesis or conversion to TKA. The most common indication for revision was tibial component loosening, followed by progression of arthritis. One patient was revised due to infection. Mean time to revision was 9.55 + 5.48 months (range: 1 to 19 months).
CONCLUSION
UKA with a robotic system provides good pain relief and functional outcomes at short-term follow-up. Ensuring correct component alignment and ligament balancing increases the probability of a favorable outcome. Proper patient selection for appropriate UKA candidates remains an important factor for successful outcomes. In combination with robotic assistance there can be a reduction in many of the failures seen with early systems.
