Reproducibility of the minimally invasive approach in unicompartmental knee replacement : 5-year follow-up of oxford phase III prosthesis

Aim. The Oxford III unicompartmental knee replacement (Biomet, UK) has proved to be efficacious in the treatment of the antero-medial arthritis of the knee. The aim of this study is to verify the reproducibility of the minimally invasive approach at an average follow-up of more than 5 years. Methods. Twenty patients (15 women and 5 men, mean age 66.7 years, range 59 to 79) with anteromedial arthritis of the knee were referred to our Institution for prosthetic knee replacement. We implanted 20 Oxford III (Biomet) prostheses with mobile bearing using antibiotic-loaded cement (Palamed G, Biomet). Results. At follow-up the HSS score averaged 87.4 (range 50 -100), with 13 excellent, 3 good, 1 adequate and 3 poor. In the radiological analysis the geometrical parameters indicated in the surgical technique relative to this prosthesis were reproduced in all the implants. The average ROM reported is 133.85°. No cases of infection, nor more serious complications were found; in the 3 patients (15%) with unsatisfactory outcome this was due to the progression of the arthritis in the lateral compartment at the last 5 years follow-up. Conclusion, the Oxford unicompartmental prosthesis is a reliable and reproducible treatment option for arthritis of the anteromedial compartment of the knee.