Bone Marrow Stimulation Technique Augmented by an Ultrapurified Alginate Gel Enhances Cartilage Repair in a Canine Model.

Background: The optimal treatment for a medium- or large-sized cartilage lesion is still controversial. Since an ultrapurified alginate (UPAL) gel enhances cartilage repair in animal models, this material is expected to improve the efficacy of the current treatment strategies for cartilage lesions. Hypothesis: The bone marrow stimulation technique (BMST) augmented by UPAL gel can induce hyaline-like cartilage repair. Study Design: Controlled laboratory study. Methods: Two cylindrical osteochondral defects were created in the patellar groove of 27 beagle dogs. A total of 108 defects were divided into 3 groups: defects without intervention (control group), defects with the BMST (microfracture group), and defects with the BMST augmented by implantation of UPAL gel (combined group). At 27 weeks postoperatively, macroscopic and histological evaluations, micro–computed tomography assessment, and mechanical testing were performed for each reparative tissue. Results: The defects in the combined group were almost fully covered with translucent reparative tissues, which consisted of hyaline-like cartilage with well-organized collagen structures. The macroscopic score was significantly better in the combined group than in the control group (P < .05). The histological scores in the combined group were significantly better than those in the control group (P < .01) and microfracture group (P < .05). Although the repaired subchondral bone volumes were not influenced by UPAL gel augmentation, the mechanical properties of the combined group were significantly better than those of the microfracture group (P < .05). Conclusion: The BMST augmented by UPAL gel elicited hyaline-like cartilage repair that had characteristics of rich glycosaminoglycan and matrix immunostained by type II collagen antibody in a canine osteochondral defect model. The present results suggest that the current technique has the potential to be one of the autologous matrix-induced chondrogenesis techniques of the future and to expand the operative indications for the BMST without loss of its technical simplicity. Clinical Relevance: The data support the clinical reality of 1-step minimally invasive cartilage-reparative medicine with UPAL gel without harvesting donor cells. [ABSTRACT FROM AUTHOR]