Abstract
Although osteochondroma is the most common benign bone tumor around the knee, osteochondroma of the tibial tuberosity is a rare presentation. Association of osteochondroma with patellar instability is even more rare.
We report an atypical presentation of solitary osteochondroma. A thirteen years-old boy presented to the clinic with a painful large osteochondroma of the tibial tuberosity associated with patellar instability and ulceration of the skin. Imaging studies showed a large osteochondral growth from the tibial tuberosity growing towards the knee joint. Excision of the mass and medialization of the tibial tuberosity was done, and the patient recovered uneventfully. Instability of the patella in this case can be attributed to lateral position of the insertion of patellar tendon caused by the osteochondroma of the tibial tuberosity.