Articular changes in experimentally induced patellar trauma

Only a few studies have described the microscopic pathology of the articular cartilage after trauma. In the present animal study, we demonstrate the effect of trauma on the articular cartilage of the patella and determine the histological changes. Traumatic injury of the patella was experimentally induced in 45 white New Zealand rabbits aged 4 to 6 months old. The articular cartilage of the patella was observed after the sacrifice of the animals immediately and at days 1, 2, 4, 8, and 15 as well as at months 1, 2 and 3 after the traumatic injury. Macroscopic, light and electron microscopic findings showed progressive articular cartilage changes with failed effort of cartilage repair. Osteoarthritic-like degeneration of the articular cartilage was found in all specimens. According to this experimental study, trauma to the articular cartilage may progress to arthritis. The reversibility of cartilage damage or the progression to arthritis seem to be associated with many factors such as the intensity and frequency of the trauma, the mechanism of injury, the intrinsic remodeling of the cartilage matrix and the capability of the articular cartilage to regenerate.