[Unicondylar knee arthroplasty in medial unicompartmental osteoarthritis: technical faults and difficulties]

The aim of this study is to evaluate both the technical problems of surgery and the clinical and radiologic outcomes of patients treated with unicondylar knee arthroplasty.

Forty-one unicondylar knee prosthesis were performed in 40 patients (3 males, 37 females; mean age 58.2 years; range 44 to 76 years) diagnosed with unicompartmental knee osteoarthritis. Technical problems encountered during surgery were noted. For evaluation of clinical outcomes, the Hospital for Special Surgery (HSS) knee score and WOMAC score were used. Radiologic evaluations were performed using the Oxford Knee Group criteria.

The radiologic evaluation determined there was more than 10 degrees varus-valgus malposition in eight patients, more than 2 mm medial tibial overhang in seven patients, the insertion of a femoral component in extension in one patient, and joint distraction in one patient. The patient with joint distraction underwent a total knee replacement after six months because of progressive pain. The mean HSS knee score improved 21 points; perfect results were obtained in 33 patients and good results in seven patients. The mean postoperative WOMAC score was reduced by 18 points, with perfect results in 33 patients, good results in six patients and a moderate result in one patient. The mean follow-up was 19 months (range 9-42).

Unicondylar knee arthroplasty is a surgical treatment method with a long-term recovery and high frequency of technical faults. Minor errors diagnosed on radiographs do not have an effect on early clinical results. Unicondylar knee arthroplasty is a good alternative surgical technique for appropriately selected patients with medial unicompartmental knee osteoarthritis.