Focal Cartilage Defects in the Knee

In comparing four patient groups awaiting knee surgery treatment, patients with focal cartilage defects in their knees presented major problems with pain and functional impairment, their quality of life evaluated by KOOS being affected to the same extent as in patients scheduled for knee replacement. Eighty four patients with knee cartilage defects ICRS grade 3 and 4 completed follow up median 6.1 years (5-8y) after the detection of the defect by knee arthroscopy. During the follow up, the patients improved their knee function, regardless of having cartilage repair or not. They did not, however, regain normal knee function. Moreover, radiological changes in the affected knee were present in 28 % at the 6-year follow up. In an experimental study the intraarticular location of a focal cartilage defect showed to predict the natural history of defect filling and subchondral mineralized tissue changes in the rabbit knee. This knowledge should be considered in evaluating results of cartilage repair in animal models. By comparing two commonly used techniques for cartilage repair in the same model, mosaic plasty resulted in higher degree of tissue filling than microfracture technique. Large standard deviations, however, imply unpredictable results in the single case – even in a standardized animal model. Mosaic plasty affected the subchondral mineralized tissues more than microfracture technique, the implications of the latter, however, being unknown