Chondral fragment of the lateral femoral trochlea of the knee in adolescents.

Most injuries to the osteochondral region in adolescents have generally been believed to occur as osteochondral fractures. However, we report three cases of pure chondral fragments of the knee in adolescents. The patients were injured during sports activities and as a result had acute limitation of ROM of the knee joint. Only one case out of three could be diagnosed by MRI, and arthroscopic examinations were needed to make a final diagnosis in the remaining two cases. Re-fixation of the fragments was performed using bio-absorbable pins. All the patients were eventually able to return to their previous level of sports activity. Two years after the operation they experienced no symptoms and MRI showed that the re-fixed fragments were continuous to the bed without any abnormal intervening signal area, suggesting successful healing. Moreover, the arthroscopic integration between the re-fixed fragment and the surrounding articular cartilage was acceptable. Chondral fragment of the lateral femoral trochlea in active adolescents should be recognized as a clear entity that can be successfully treated by re-fixation.