Osteochondral Repair with Autologous Cartilage Transplantation with or without Bone Grafting: A Short Pilot Study in Mini-Pigs

Abstract

Objective Treatment strategies for osteochondral defects, for which particulated autologous cartilage transplantation (PACT) is an emerging treatment strategy, aim to restore the structure and function of the hyaline cartilage. Herein, we compared the efficacy of PACT with control or human transforming growth factor-β (rhTGF-β), and clarified the necessity of bone graft (BG) with PACT to treat shallow osteochondral defects in a porcine model. Design Two skeletally mature male micropigs received 4 osteochondral defects in each knee. The 16 defects were randomized to (1) empty control, (2) PACT, (3) PACT with BG, or (4) rhTGF-β. Animals were euthanized after 2 months and histomorphometry, immunofluorescence analysis, semiquantitative evaluation (O’Driscoll score), and magnetic resonance observation of cartilage repair tissue (MOCART) score were performed. Results Hyaline cartilages, glycosaminoglycan synthesis, and collagen type II staining were more abundant in the PACT than in the control and rhTGF-β groups. The O’Driscoll score was significantly different between groups ( P < 0.001), with both PACT groups showing superiority ( P = 0.002). PACT had the highest score ( P = 0.002), with improved restoration of subchondral bone compared with PACT with BG. The MOCART score showed significant differences between groups ( P = 0.021); MOCART and O’Driscoll scores showed high correlation (r = 0.847, P < 0.001). Conclusion Treatment of osteochondral defects with PACT improved tissue quality compared with that with control or rhTGF-β in a porcine model. BG, in addition to PACT, may be unnecessary for shallow osteochondral defects. Clinical Relevance. BG may not be necessary while performing PACT.