Late symptomatic heterotopic ossification of the patellar tendon after medial parapatellar intramedullary nailing of the tibia.

This article describes a case of a 21-year old man who presented with symptomatic heterotopic ossification of the patellar tendon 3.5 years postinjury. The patient sustained an open tibia fracture during a fall and was treated by reamed intramedullary nailing through a medial paratendinous approach. Radiographic evidence of heterotopic ossification in the patellar tendon was first noted at the 4-week follow-up. He presented at 3.5 years postinjury with new-onset anterior knee pain and reported no interval trauma to the knee. Radiographs revealed a well-circumscribed area of calcification within the patellar tendon, which was excised within 2 weeks. On excision, the patient's symptoms had resolved. This case is unique because the patellar tendon was not violated at initial or subsequent surgeries, and because of the delayed presentation of heterotopic bone within the patellar tendon. To date, there have been only 3 reported cases of heterotopic ossification of the patellar tendon after intramedullary nailing of the tibia. We present a case of late symptomatic heterotopic ossification of the patellar tendon after medial paratendinous intramedullary nailing of an open tibia shaft fracture.