Two Year Follow-up of the Preservation Unicompartmental Knee Implant.

Reported results of unicondylar knee arthroplasty (UKA) have mixed reviews in comparison with results of tri-compartmental knee arthroplasty (TKA). We prospectively evaluated the short-term results (2 years) of a newer design of a UKA implant (Preservation UKA) with a cobalt-chromium femoral component and an all polyethylene tibial component. Seventy-two patients with intact ligaments and loss of only medial articular cartilage received the Preservation prosthesis. Data were obtained using WOMAC, Knee Society score (KSS), and standard radiographs. WOMAC scores improved by 24 points and KSS improved by 33 points at 2-year follow-up. Mean flexion increased by 4° to126° at 2 years. On X-ray, only one patient had a radiolucency. No fractures occurred. Two knees were revised due to clinical symptoms of medial compartment pain. This 2-year follow-up study of the Preservation UKA shows promising early results. Long-term data would be necessary to compare results with TKA or other unicompartmental replacements.