Despite much research, the causes remain unclear but include repetitive physical trauma, ischemia (restriction of blood flow), hereditary and endocrine factors, avascular necrosis (loss of blood flow), rapid growth, deficiencies and imbalances in the ratio of calcium to phosphorus, and problems of bone formation. Although the name<unk> " implies inflammation, the lack of inflammatory cells in histological examination suggests a non-inflammatory cause. It is thought that repetitive microtrauma, which leads to microfractures and sometimes an interruption of blood supply to the subchondral bone, may cause subsequent localized loss of blood supply or alteration of growth. Trauma, rather than avascular necrosis, is thought to cause<unk>  in juveniles. In adults, trauma is thought to be the main or perhaps the sole cause, and may be endogenous, exogenous or both. The incidence of repetitive strain injury in young athletes is on the rise and accounts for a significant number of visits to primary care; this reinforces the theory that<unk>  may be associated with increased participation in sports and subsequent trauma. High-impact sports such as gymnastics, soccer, basketball, lacrosse, football, tennis, squash, baseball and weight lifting may put participants at a higher risk of<unk>  in stressed joints (knees, ankles and elbows). Recent case reports suggest that some people may be genetically predisposed to<unk> . Families with<unk>  may have mutations in the aggrecan gene. Studies in horses have implicated specific genetic defects.
Osteochondritis dissecans
Tennis elbow
Osteochondrosis
Osteochondroma
Myositis ossificans
Osteitis pubis
Osteitis fibrosa cystica
Synovial osteochondromatosis