Purpose: The HemiCAP® implant for femoral resurfacing treatment of cartilage lesions was introduced in 2003. We present outcome from a prospective cohort study of 61 patients with both trochleal and condylar lesions treated with the HemiCAP® implant.
Methods: From 2007 to 2012, 61 patients were treated with femoral resurfacing using the HemiCAP implant. There were 36 femoral condyle implants and 25 trochleal implants. Indication for treatment with HemiCAP implant was symptomatic cartilage lesion at the femoral condyle demonstrated by MRI or arthroscopy, which was ICRS grade 3-4 and size less than 4 cm2. There were 24 males and 37 females with a median age of 49 (range 35-65) years. Patients were followed for 2 years with Knee Society subjective outcome scores (KSS), pain scores and radiographic evaluations and for 7 years with complications and reoperations.
Results: At 2-year follow-up, mean KSS was improved from 52 (6.2) to 90 (7.9), mean KSS function score was improved from 45 (7.5) to 92 (8.3), and mean Pain score improved from 7.1 (0.7) to 1.8 (1.7). Twenty-three per cent of implants were revised within 7 years to arthroplasty due to progression of cartilage lesions, progression of osteoarthritis, or increased knee pain. No difference between females and males was found for reoperation rate.
Conclusion: The present study demonstrated improved subjective outcome and reduced pain after femoral resurfacing using the HemiCAP implant in a relatively large cohort of patients with symptomatic cartilage lesions. A concerning 23 % reoperation rate with conversion to arthroplasty was found. Femoral resurfacing implantation treatment can be a temporary treatment for cartilage lesions expected to develop into osteoarthritis and for younger patients not eligible for arthroplasty treatment.
Level of evidence: IV.
Keywords: Cartilage injury; Condylar implant; Femoral resurfacing; Knee prosthesis.