Osteochondral lesions of the knee: a new one-step repair technique with bone-marrow-derived cells.

Osteochondral lesions of the knee are defects of the cartilaginous surface and underlying subchondral bone, most frequently traumatic in origin1. These lesions are predominantly located on the medial femoral condyle, and associated ligamentous or meniscal pathology is reported in 40% of cases2,3 (Fig. 1). Biomechanical studies have demonstrated increased stress concentration on the rim of the osteochondral defect, which may have important implications for cartilage longevity4. Due to poor hyaline cartilage repair capability, larger osteochondral lesions of the knee are associated both with immediate significant clinical impairment and with symptoms appearing approximately one decade earlier than the degenerative cartilage changes that are associated with idiopathic osteoarthritis5. Recently, bone-marrow-derived mesenchymal stem cells have been identified as a new option for the treatment of osteochondral defects, and a new one-step technique for bone-marrow-derived mesenchymal stem-cell transplantation has been proposed19. After encouraging results were obtained in the ankle19, bone-marrow-derived mesenchymal stem-cell transplantation is now being utilized for osteochondral lesions of the knee. The aim of this study was to investigate the validity of the "one-step" technique in repair of osteochondral lesions of the knee and to present the results of a series of twenty patients who were consecutively treated.