Unusual patellar tendon injury in an adolescent runner with generalised ligamentous laxity.

A case is reported of an acute traction injury of the patellar tendon in a boy of 14 with joint hypermobility. Such injuries are unusual but early diagnosis and surgical repair lead to a good long term outcome. In adolescents participating in sports, the awareness of the possibility of a rare knee extensor mechanism injury is essential for a successful outcome.