Refractory heterotopic ossification with complications

Heterotopic ossification (HO) following spinal cord injury can lead to various complications, including venous thrombosis, autonomic dysreflexia, and pressure ulcers. We report refractory, complicated HO in a 19-year-old man with C8 incomplete tetraplegia. He first presented at 9 weeks postinjury with fever and swelling of his right leg. Ultrasound indicated a deep venous thrombosis (DVT). Persistent symptoms prompted triple-phase bone scan and magnetic resonance imaging (MRI), which revealed HO compressing the right external iliac vein and no evidence of DVT. The HO was complicated by hypercoagulability.

The HO was refractory to oral indomethacin and etidronate; therefore, intravenous etidronate was instituted, resulting in only a transient decrease in alkaline phosphatase. Local irradiation of the right hip did not decrease the activity of HO. The patient was discharged on oral etidronate, indomethacin, and warfarin. This complicated case raises issues regarding early diagnosis and aggressive treatment of HO, as well as treatment of associated hypercoagulability.