[Midterm results of Oxford phase 3 unicondylar knee arthroplasty for medial osteoarthritis].

OBJECTIVES: We evaluated midterm results of Oxford phase 3 unicondylar knee arthroplasty (UKA) in patients with medial osteoarthritis.

METHODS: Twenty-seven patients (24 females, 3 males; mean age 57 years; range 47 to 73 years) underwent Oxford phase 3 UKA with the diagnosis of medial knee osteoarthritis. All patients had primary osteoarthritis but one with spontaneous osteonecrosis. Nine knees were Ahlback grade 2, and 18 knees were grade 3. All femoral and tibial components were cemented and mobile tibial polyethylene inserts were used in all the patients. Pre- and postoperative evaluations were made using the Knee Society clinical rating system. The mean follow-up was 28 months (range 24 to 36 months).

RESULTS: Compared to the preoperative values, significant improvements were obtained in the following at final follow-up (p<0.05): knee flexion (106.4 degrees and 117.4 degrees , respectively), tibiofemoral angle (7 degrees varus and 1 degrees valgus), knee score (47.5 and 78.9), and functional knee score (48.7 and 83.6). Only two patients needed blood transfusion. No major complications occurred including infection, deep vein thrombosis, pulmonary emboli, and neurovascular injury. Two patients underwent revision surgery at postoperative 8 and 10 months, respectively, because of progressive collapse of the tibial plateau. Knee Society clinical scores were excellent or good in 21 (77.8%), moderate in four (14.8%), and poor in two (7.4%) patients. The corresponding figures for functional results were 23 (85.2%), 2 (7.4%), and 2 (7.4%).

CONCLUSION: Our results demonstrate that Oxford phase 3 UKA is effective with considerable success in the treatment of medial osteoarthritis.