Novel Nano-composite Multilayered Biomaterial for Osteochondral Regeneration A Pilot Clinical Trial

Background: In recent years, there has been an increasing interest in and awareness of the importance of subchondral bone, for its role in the pathogenesis of articular surface damage and for the care that should be taken when treating such damage. Purpose: The objective of this pilot clinical study was to test the safety and performance of a newly developed type I collagen-hydroxyapatite nanostructured biomimetic osteochondral scaffold that aims to regenerate cartilage and subchondral bone. Study Design: Case series; Level of evidence, 4. Methods: A multilayer gradient nano-composite scaffold was obtained by nucleating collagen type I fibrils with hydroxyapatite nanoparticles. Thirty patients (9 female, 21 male; mean age, 29.3 years) with knee chondral or osteochondral lesions were treated with scaffold implantation. Lesion size varied from 1.5 cm(2) to 6.0 cm(2). Twenty-eight patients were followed for 2 years and were clinically evaluated using the International Knee Documentation Committee and Tegner scores. At final follow-up, magnetic resonance imaging evaluation was performed in 24 patients, and they were evaluated with the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score. Results: The Tegner and International Knee Documentation Committee objective and subjective scores improved significantly from the baseline evaluation to the 6-, 12-, and 24-month follow-ups. Further analysis showed a slower recovery but the same results for patients who presented with adverse events, for older patients, for patients who underwent previous surgery, and for those with patellar lesions. In contrast, a faster recovery was observed in active patients. At magnetic resonance imaging evaluation, complete filling of the cartilage and complete integration of the graft was shown in 70% of the lesions. However, the subchondral lamina and bone were considered intact in a minority of cases (7% and 47%, respectively). Conclusion: This open 1-step procedure was used for the treatment of chondral and osteochondral knee defects. The present pilot study highlighted the safety and potential clinical benefit of the graded biomimetic osteochondral scaffold in promoting bone and cartilage tissue restoration by itself and with good clinical and magnetic resonance imaging results at the 2-year follow-up.