Repair of porcine articular cartilage defect with a biphasic osteochondral composite

Abstract

Autologous chondrocyte implantation (ACI) has been recently used to treat cartilage defects. Partly because of the success of mosaicplasty, a procedure that involves the implantation of native osteochondral plugs, it is of potential significance to consider the application of ACI in the form of biphasic osteochondral composites. To test the clinical applicability of such composite construct, we repaired osteochondral defect with ACI at low cell-seeding density on a biphasic scaffold, and combined graft harvest and implantation in a single surgery. We fabricated a biphasic cylindrical porous plug of DL-poly-lactide-co-glycolide, with its lower body impregnated with b-tricalcium phosphate as the osseous phase. Osteochondral defects were surgically created at the weight-bearing surface of femoral condyles of Lee-Sung mini-pigs. Autologous chondrocytes isolated from the cartilage were seeded into the upper, chondral phase of the plug, which was inserted by press-fitting to fill the defect. Defects treated with cell-free plugs served as control. Outcome of repair was examined 6 months after surgery. In the osseous phase, the biomaterial retained in the center and cancellous bone formed in the periphery, integrating well with native subchondral bone with extensive remodeling, as depicted on X-ray roentgenography by higher radiolucency. In the chondral phase, collagen type II immunohistochemistry and Safranin O histological staining showed hyaline cartilage regeneration in the experimental group, whereas only fibrous tissue formed in the control group. On the International Cartilage Repair Society Scale, the experimental group had higher mean scores in surface, matrix, cell distribution, and cell viability than control, but was comparable with the control group in subchondral bone and mineralization. Tensile stress-relaxation behavior determined by uni-axial indentation test revealed similar creep property between the surface of the experimental specimen and native cartilage, but not the control specimen. Implanted autologous chondrocytes could survive and could yield hyaline-like cartilage in vivo in the biphasic biomaterial construct. Pre-seeding of osteogenic cells did not appear to be necessary to regenerate subchondral bone. ß

Treatment of osteochondral defects of the talus

“…294 Jiang et al investigated repair with a biphasic osteochondral composite consisting of b-tricalcium phosphate and dl-polylactide-co-glycolide seeded with autologous chondrocytes using single-stage surgery. 201 Commercially available composite implants have become available for the treatment of OCDs of the knee (TruFit Plug ® , Smith & Nephew, San Antonio, TX, USA). 452 Our research group is currently investigating the applicability of a novel resurfacing technique of the medial talar dome by means of a contoured metal implant (HemiCAP ® , Arthrosurface Inc., Franklin, MA, USA).…”

“…32,147,312 Therefore, experimental studies focus on improvement of these methods and development of alternativ es. 72,138,140,201,252,411,451 However, almost all studies investigate articular defects of the knee, while the ankle joint is rarely investigated. 81 These knee studies cannot reliably be extrapolated to patients with ankle defects, because biomechanical and biochemical properties of the knee and ankle are clearly different.…”

Bone Marrow-Derived Cell Concentrates Have Limited Effects on Osteochondral Reconstructions in the Mini Pig

“…7 Most recent studies have demonstrated benefits of cell seeding on histological and mechanical properties of osteochondral reconstructions. 8,9 Other groups could not detect the mechanical superiority of cell-seeded constructs compared with empty scaffolds. 10 Irrespective of whether cells are used or not, reconstruction of the subchondral bone remains the key element to osteochondral reconstruction.…”

Oligo[poly(ethylene glycol)fumarate] Hydrogel Enhances Osteochondral Repair in Porcine Femoral Condyle Defects

“…It was surprising to find the quality of repair tissue in our control group surpassed the thin layer of sparsely populated fibrous tissue, commonly found to occupy the osteochondral defects of large-animal models [14,25]. This was despite the use of skeletally mature animals, as germinal cells from the physis of skeletally immature animals [1] could contribute to cartilage regeneration.…”