Five-Year Follow-up of a Multicenter Randomized Controlled Trial Comparing an Aragonite-Based Scaffold With Microfracture and Debridement for Chondral and Osteochondral Knee Lesions

Chondral/osteochondral knee lesions are commonly encountered and often associated with progression of osteoarthritis (OA). Nevertheless, knee repair trials have traditionally excluded patients with concurrent mild to moderate OA. To compare the clinical and safety outcomes of knee repair with an aragonite-based osteochondral implant with outcomes of surgical standard of care (SSOC) in patients with chondral/osteochondral knee lesions, including those with mild to moderate OA. Randomized controlled trial; Level of evidence, 1. Investigators at 26 centers across 8 countries enrolled adult patients (21-75 years of age) with &#x2264;3 cartilage defects of International Cartilage Regeneration & Joint Preservation Society grade &#x2265;3a located on the femoral condyles and/or trochlea, total treatable area 1 to 7 cm, bony defect depth &#x2264;8 mm, and Kellgren-Lawrence knee OA score of 0 to 3. Patients were randomized 2:1 to receive an aragonite-based implant or SSOC (arthroscopic debridement or microfracture) and followed for 5 years. The primary endpoint was improvement in overall Knee injury and Osteoarthritis Outcome Score (KOOS). Secondary endpoints included percentage of responders (minimum overall KOOS improvement &#x2265; 30 points), patient-reported outcomes (KOOS subscale values and International Knee Documentation Committee subjective score), treatment failure (ie, need for any secondary treatment), and treatment-emergent adverse events. A covariate analysis compared primary/secondary outcomes between patients with no to minimal and mild to moderate OA. In total, 167 patients underwent knee repair with the study implant and 84 with SSOC, with follow-up compliance rates of 88.4% and 83.1%, respectively, at 5 years. The mean baseline overall KOOS values were comparable between the implant (41.2 &#xb1; 13.1) and SSOC (41.7 &#xb1; 12.4) groups. By the final follow-up, improvement was significantly greater for the implant group (81.0 &#xb1; 23.0 vs 59.1 &#xb1; 25.2; 22.6-point difference; 95% CI, 16.6-28.7). The overall KOOS responder rate was 74.7% in the implant group and 29.6% in the SSOC group. The implant group experienced significantly superior outcomes between baseline and the final follow-up for all secondary patient-reported outcome measures. Treatment failure rate was significantly higher with SSOC than the implant (35.7% vs 15.0%;< .001). Among patients with mild to moderate OA, the implant group exhibited a higher overall KOOS responder rate (74.6% vs 36.2%) and lower failure rate (13.2% vs 40.7%;< .001) than the SSOC group. The results confirmed that the aragonite-based scaffold is both safe and superior to SSOC in improving clinical outcomes at up to 5 years' evaluation, as well as in patients with mild to moderate OA.