There is no widely accepted method to repair articular cartilage defects. Bone marrow mesenchymal cells have the potential to differentiate into bone, cartilage, fat and muscle. Bone marrow mesenchymal cell transplantation is easy to use clinically because cells can be easily obtained and can be multiplied without losing their capacity of differentiation. The objective of this study was to apply these cell transplantations to repair human articular cartilage defects in osteoarthritic knee joints.
Twenty-four knees of 24 patients with knee osteoarthritis (OA) who underwent a high tibial osteotomy comprised the study group. Adherent cells in bone marrow aspirates were culture expanded, embedded in collagen gel, transplanted into the articular cartilage defect in the medial femoral condyle and covered with autologous periosteum at the time of 12 high tibial osteotomies. The other 12 subjects served as cell-free controls.
In the cell-transplanted group, as early as 6.3 weeks after transplantation the defects were covered with white to pink soft tissue, in which metachromasia was partially observed. Forty-two weeks after transplantation, the defects were covered with white soft tissue, in which metachromasia was observed in almost all areas of the sampled tissue and hyaline cartilage-like tissue was partially observed. Although the clinical improvement was not significantly different, the arthroscopic and histological grading score was better in the cell-transplanted group than in the cell-free control group.
This procedure highlights the availability of autologous culture expanded bone marrow mesenchymal cell transplantation for the repair of articular cartilage defects in humans.