Abstract
Background
Focal resurfacing can treat localised articular damage of the knee not appropriate for arthroplasty or biological repair. Independent results on these implants are limited. We previously published early results showing significantly improved Knee Injury & Osteoarthritis Outcome Score (KOOS4) without complication or re-operation, demonstrating this system gives good analgesia and functional improvement in selected patients. We present long-term follow-up of these patients.
Methods
We prospectively evaluated medium- to long-term results in patients with localised, full-thickness articular cartilage defects of the knee undergoing HemiCAP resurfacing. All procedures were performed by one consultant surgeon. Post-operative rehabilitation was standardised. Outcome measures were KOOS4 score, visual analogue score (VAS), Kellgren and Lawrence arthritis grade, and re-operation rates.
Results
Six patients were evaluated with mean follow-up time of 74 months (range 61–96). Mean age was 44.8 years (range 33–51). One lateral and five medial compartments were resurfaced. Mean pre-operative KOOS4 was 39.1, mean 22-month follow-up KOOS4 improved significantly to 79.6, and mean latest follow-up KOOS4 remained good at 71.3. Mean VAS was 8.8 at latest follow-up. There was no loosening, migration or increase in osteoarthritis grade. One patient underwent revision to unicondylar knee replacement for pain after three years with comparable results at another centre (medial compartment, two year follow-up pre-revision KOOS4 84.6, latest follow-up post-revision KOOS4 73.6, VAS 6). Cause of pain was unclear (heel pain causing prolonged altered weight-bearing or failure of HemiCAP).
Conclusion
Our results demonstrate that the use of the joint-preserving HemiCAP system provides good pain relief and functional improvement in both the short and longer-term. Few studies assess functional outcomes of focal resurfacing for localised full thickness articular cartilage defects. Our study assesses both the contemporaneous and time-dependent behaviour of focal resurfacing. We believe this is one of the longest follow-up series to date.
