Oxford Phase 3 Unicompartmental Knee Arthroplasty (UKA): Clinical and radiological results of minimum follow-up of 2 years.

Background. Since the introduction minimally invasive techniques, interest in unicompartmental knee arthroplasty (UKA) has rapidly increased. This minimally invasive approach preserves the anatomy of the knee with less damage to extensor mechanisms, less morbidity, and quicker post-operative recovery. The purpose of our study was to evaluate this new treatment option for anteromedial osteoarthritis, both clinically and radiographically, and to identify any possible drawbacks. Material and methods. Between January 1999 and August 2003 88 consecutive Oxford Phase 3 UKAs were implanted by a single surgeon. All patients with a minimal follow-up (FU) period of 2 years were pre- and post- operatively clinically evaluated by the American Knee Society (AKS) Score and radiographically according to the Oxford Centre criteria, including fluoroscopy. Results. Twenty-eight patients with 30 prostheses with a minimal follow-up period 2 years (2.54 +/- 0.48 yrs) were included in this study. The AKS Knee, Function and Pain Score improved significantly at 2-year FU compared to the preoperative score, the preoperative varus deformity was corrected into alignment in all cases. Conclusions. Clinical and radiographical results of the Oxford Phase 3 prosthesis using a minimally invasive surgical technique confirmed previous good results achieved by the standard technique. Evaluation of our patients at a minimum FU of 2 years revealed a significant improvement of AKS scores. Postoperatively knee joint deformity was corrected into a physiological valgus alignment. Patient satisfaction is high, and the prosthesis provides good outcome for patients with anteromedial osteoarthritis when strict indication criteria are considered.