Osteochondral Autograft Transplantation Technique Augmented by an Ultrapurified Alginate Gel Enhances Osteochondral Repair in a Rabbit Model

Abstract

Background: One of the most important limitations of osteochondral autograft transplantation (OAT) is the adverse effect on donor sites in the knee. To decrease the number and/or size of osteochondral defects, we devised a method with biomaterial implantation after OAT. Hypothesis: OAT augmented by ultrapurified alginate (UPAL) gel enhances cartilage repair capacity. Study Design: Controlled laboratory study. Methods: Seventy-five osteochondral defects in rabbits were divided into 3 groups: osteochondral defects with OAT alone, defects with OAT augmented by UPAL gel (combined group), and defects without intervention as controls. Macroscopic and histological evaluations of the reparative tissues were performed at 4 and 12 weeks postoperatively. Histological evaluation of graft cartilage degradation was also performed. To evaluate the effects of UPAL gel on graft healing, repaired bone volumes and osseointegration of the graft were evaluated. Collagen orientation and the mechanical properties of the reparative tissue and graft cartilage were also evaluated qualitatively. Results: The macroscopic and histological evaluations of the combined group were significantly superior to the other groups at 12 weeks postoperatively. Regarding degenerative change of the graft, the histological scores of the combined group were significantly higher than those of the OAT-alone group. The values of repaired subchondral bone volumes and osseointegration of the graft were almost identical in both groups. Collagen orientation and the mechanical properties of the reparative tissue and graft cartilage were significantly better in the combined group than in the other groups. Conclusion: Administration of UPAL gel in OAT enhanced cartilage repair and protected graft cartilage without inhibiting subchondral bone repair and graft survival. Clinical Relevance: OAT augmented by UPAL gel decreases the number and/or size of osteochondral grafts, minimizing the risk of donor site morbidity. This combination technique has the potential to improve clinical outcomes and expand the surgical indications for OAT.

Acellular Cartilage Repair Technique Based on Ultrapurified Alginate Gel Implantation for Advanced Capitellar Osteochondritis Dissecans

“…19,40 The low endotoxin level enables safe clinical application of the UPAL gel because it does not induce immunologic reactions to the implanted material. 11,14 The current clinical and radiographic findings suggested that no infections or allergic reactions occurred in any of the 5 patients. Additionally, second-look arthroscopy and biopsy provided visual confirmation that there were no adverse effects derived from the material in the soft tissues of the elbow joint and cartilage, thereby indicating a reasonable safety profile.…”

“…Previous studies have demonstrated that UPAL gel administration without exogenous cell implantation induces hyaline-like cartilage repair, possibly because this hydrogel retains migrated cells and enhances cellular proliferation and chondrogenic differentiation. 2,11 Using a canine model, Baba et al 1 Recent studies have demonstrated that mosaicplasty provides favorable clinical outcomes in patients with large capitellar OCD lesions. 16,17 Mosaicplasty is based on the concept that osteochondral grafts harvested from the articular cartilage of the knee joint provide an adequate biomechanical environment and friction pattern similar to that of the normal elbow joint.…”

Ultrapurified Alginate Gel Containing Bone Marrow Aspirate Concentrate Enhances Cartilage and Bone Regeneration on Osteochondral Defects in a Rabbit Model

“…UPAL gel (Sea Matrix; Mochida Pharmaceutical Co) with a molecular weight of 1700 kDa, as reported previously, was used in this experiment. 12 Generally, edible alginate is made from natural kelp, which has some impurities such as endotoxin that could cause a xenobiotic reaction. To prevent this, the endotoxin level of UPAL gel has been reduced to a sufficiently low level (5.76 EU/g), which passes the biological safety test for implantation in vivo.…”

Scaffold-Mediated Gene Delivery for Osteochondral Repair

“…Hydrogels are well adapted for cartilage repair as they have high water contents mimicking cartilage-based ECM glycosaminoglycans [ 86 ] and biocompatibility, often with lower mechanical properties compared with solid scaffolds [ 87 , 88 ]. Natural polymer biomaterials such as collagen [ 89 ], alginate [ 90 ], gellan gum [ 91 ], or silk fibroin [ 92 ] have been studied as scaffolds for cartilage repair due to their biocompatible nature promoting proliferation and differentiation of the encapsulated cells which makes them promising systems in various tissue engineering approaches [ 74 , 92 , 93 ]. Solid scaffolds are highly porous structures, allowing for migration and infiltration of cells from the surrounding tissue.…”