Wakitani’s group was the first to report on clinical application of mesenchymal stem cells for articular cartilage defects. They transplanted autologous culture-expanded bone marrow stem cells into nine full-thickness articular cartilage defects of the patello-femoral joints in the knees of three patients. Single-passage cells were collected, embedded in a collagen solution (5×10[6] cells/ml), gelated, transplanted into the defect and covered with autologous periosteum or synovium. Six months later, clinical symptoms had improved; this improvement was maintained  over the 17-27 months follow-up period. Histology of one patient, 12 months after the transplantation, revealed repair of the defect by fibrocartilaginous tissue. Magnetic resonance imaging of another patient, 1 year after transplantation, revealed complete coverage of the defect (Wakitani et al., 2007)