Purpose: The UniCAP (®) implant for femoral resurfacing treatment of large cartilage lesions and early OA was introduced in 2006. The outcome of the present study is from a prospective cohort study of 64 patients, followed 2 years clinically and 7 years for revisions.
Methods: From 2009 to 2013, 64 patients were treated with femoral resurfacing using the UniCAP implant. Indication for treatment with UniCAP implant was symptomatic huge cartilage lesion or early OA at the femoral condyle demonstrated by MRI or arthroscopy, which was ICRS grades 3-4 and more than 4 cm(2). There were 28 males and 36 females with a median age of 51 (range 35-65) years. Patients were followed for 2 years clinically with Knee Society subjective outcome scores (KSS), pain scores and radiographic evaluations and for 7 years with complications and reoperations.
Results: At 2 years, the follow-up mean KSS improved from 49 (6.9) to 88 (17.1), the mean KSS function score improved from 46 (8.0) to 90 (17.1), and the mean Pain score improved from 7.4 (0.5) to 2.3 (1.4). 47 % of the implants were revised within 7 years to arthroplasty due to the progression of cartilage lesions, progressing of osteoarthritis or increased knee pain. The reoperation rate did not show any significant difference between females and males. The Kaplan-Meier survival rate was 50 % at 7 years, no difference among females and males.
Conclusion: The present study demonstrated an improved subjective outcome and reduced pain after femoral resurfacing using the UniCAP (®) implant in a relatively large cohort of patients with symptomatic large cartilage lesions or early OA. A 47 % reoperation rate with conversion to arthroplasty was found. The femoral resurfacing implantation can be a temporary treatment for large cartilage lesions or early OA that is expected to develop into osteoarthritis. For younger patients who are ineligible for arthroplasty treatment, this implant can offer a temporary solution.
Level of evidence: IV.
Keywords: Condylar implant; Early OA; Femoral resurfacing; Knee prosthesis; Large cartilage lesions.