The defects of the articular cartilage structure are not replaced unless the subchondral plate has been breached. However, following the creation of a defect in the subchondral plate, the area is filled in with a fibrous tissue which gradually transforms to hyaline cartilage. The porous nontoxic materials of both biologic and synthetic origin have reportedly been used as matrices for repairing bone and cartilage. Following implantation, carbon fibre, chemically inert and well-tolerated by the body, induces a proliferation of ordered fibrous tissue. We implanted carbon fiber pads in osteochondral defects in rabbits. Those repairs were compared to control holes with no implants. The pads appeared to induce the gross appearance of a restored joint surface, mechanically strong to loading for periods from 2 to 6 weeks. Also, carbon fiber pads promoted the healing of the osteochondral defects in the rabbit femoral condyle, supplying well-organized cartilagenous tissue over repaired subchondral bone. The use of carbon fiber pads as implant material is suggested for the restoration of articular surface in osteoarthritis and osteochondritis dissecans.
Animals ; *Carbon ; Cartilage, Articular/surgery/*ultrastructure ; Knee Joint/surgery/*ultrastructure ; Microscopy, Electron, Scanning ; *Prostheses and Implants ; Rabbits

OBJECTIVETo investigate whether the unevenness of articular surface would affect the osteochondral repair.

METHODSEight Shanghai Chongming 6-months-old masculine goats with a mean weight of 25 kg were used in this study. Different unevenness, which were 0.5 mm, 1.0 mm, 2.0 mm protrude or concavity, were created on the weight-bearing portion of the medial femoral condyles of the goats. The goats were sacrificed 12 weeks later and were observed with the general observation, HE staining and transmission electron microscope. To evaluate the microscopic morphology, a histological grading scale described by O'Driscoll, Keeley and Salter was used.

RESULTSThe general observation and HE staining showed that the unevenness of 0.5 mm or 1.0 mm protrudes or concavity could be repaired to get the surface smooth on the whole. The transmission electron microscope showed that the reparative tissues were the same as the normal cartilage. The 2.0 mm depth couldn't be repaired satisfactorily. The transmission electron microscope showed that the fiber bundle proliferated and the chondrocytes degenerated. The scores of the 2.0 mm depth were significantly lower than that of the 0.5 mm or 1.0 mm (P < 0.05).

CONCLUSIONThe unevenness could have an influence on the repair. The limited unevenness could be repaired by itself.

Animals ; Cartilage, Articular ; pathology ; surgery ; ultrastructure ; Male ; Microscopy, Electron, Scanning ; Sheep ; Wound Healing

BACKGROUNDOsteochondral lesion repair is a challenging area of orthopedic surgery. Here we aimed to develop an extracellular matrix-derived, integrated, biphasic scaffold and to investigate the regeneration potential of the scaffold loaded with chondrogenically-induced bone marrow-derived mesenchymal stem cells (BMSCs) in the repair of a large, high-load-bearing, osteochondral defect in a canine model.

METHODSThe biphasic scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and characterized by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Osteochondral constructs were fabricated in vitro using chondrogenically-induced BMSCs and a biphasic scaffold, then assessed by SEM for cell attachment. Osteochondral defects (4.2 mm (diameter) × 6 mm (depth)) were created in canine femoral condyles and treated with a construct of the biphasic scaffold/chondrogenically-induced BMSCs or with a cell-free scaffold (control group). The repaired defects were evaluated for gross morphology and by histological, biochemical, biomechanical and micro-CT analyses at 3 and 6 months post-implantation.

RESULTSThe osteochondral defects of the experimental group showed better repair than those of the control group. Statistical analysis demonstrated that the macroscopic and histologic grading scores of the experimental group were always higher than those of the control group, and that the scores for the experimental group at 6 months were significantly higher than those at 3 months. The cartilage stiffness in the experimental group (6 months) was (6.95 ± 0.79) N/mm, 70.77% of normal cartilage; osteochondral bone stiffness in the experimental group was (158.16± 24.30) N/mm, 74.95% of normal tissue; glycosaminoglycan content of tissue-engineered neocartilage was (218 ± 21.6) µg/mg (dry weight), 84.82% of native cartilage. Micro-CT analysis of the subchondral bone showed mature trabecular bone regularly formed at 3 and 6 months, with no significant difference between the experimental and control groups.

CONCLUSIONThe extracellular matrix-derived, integrated, biphasic scaffold shows potential for the repair of large, high-load-bearing osteochondral defects.

Animals ; Bone Marrow Cells ; cytology ; Bone Regeneration ; physiology ; Cartilage, Articular ; surgery ; Dogs ; Extracellular Matrix ; chemistry ; Mesenchymal Stromal Cells ; cytology ; ultrastructure ; Microscopy, Electron, Scanning ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry ; X-Ray Microtomography