As the athlete prepares to jump or starts to land, the knee begins to flex, with the quadriceps muscle and patellar tendon pulling hard on the tubercle. The tubercle, which is not fully fused, is pulled off with the tendon. The patient may have trouble going up and down steps. The physical exam shows focal tenderness at the site of the injury, often with significant ecchymosis and swelling. The patient will be unable to bear weight on the leg or extend the knee because of pain and disruption of the quadriceps mechanism.
Management is dependent on the fracture type.
For nondisplaced type I fractures, I would immobilize the knee using an immobilizer or a cast for 10 days to 2 weeks, for comfort and to allow healing. The patient should avoid jumping activities for 4 additional weeks. More complex injuries require open reduction and fixation. The knee is immobilized for 3 weeks after surgery, followed by progressive rehabilitation. It is usually 2 to 3 months before the patient returns to full athletic activity after an open reduction.