[Unicompartmental vs. Total Knee Arthroplasty for Medial Osteoarthritis]

Background In end-stage medial osteoarthritis, the surgeon can decide whether to use unicompartmental or total knee arthroplasty for operative treatment of the patient. Despite the available literature there is a lack of evidence to suggest if one procedure can be rated as being superior to the other. With increasing demand for knee arthroplasty, treatment with the highest expectation of success will be of particular interest. The purpose of this manuscript was to analyse and compare the available literature on unicompartmental vs. total knee arthroplasty for the treatment of medial osteoarthritis. Material and Methods In this review of literature, the two procedures were compared regarding their clinical outcome, implant survival, and complication rates. Results Regarding the clinical outcome the unicompartmental knee arthroplasty was shown to be superior over total knee arthroplasty. However, studies were mostly retrospective and groups were also different preoperatively. Patients treated with unicompartmental knee arthroplasty had better preoperative range of motion and function scores. Unicompartmental and total knee arthroplasty showed comparably increased functional scores. Taking the implant survival as parameter, institutional registries, multicenter studies and arthroplasty registries found total knee arthroplasties to have a significantly better long-term survival in comparison to unicompartmental knee arthroplasty. However, data might be biased by the lower threshold to revise unicompartmental knee arthroplasty due to expected simple revision and more subjective indications for revision. Looking at the complication rate, one has to differentiate between general and implant-specific complications. While the unicompartmental knee arthroplasty was shown to be advantageous in terms of general complications and mortality, it was also shown to be inferior in terms of implant-specific complications. Conclusion The available literature does not show one procedure to be superior to the other. The trend to a better clinical outcome and a lower mortality rate is advantageous for unicompartmental knee arthroplasty, while the better long-term survival and a lower risk of implant-specific complications may make total knee arthroplasty preferable.