Heterotopic ossification around the hip joint in spinal cord injured patients.

Thirty patients with heterotopic ossification following spinal injuries were divided into acutely-injured and post-surgical groups. Patients in the acutely injured group had symptoms of heterotopic ossification within 6 months of injury. The formation and maturation of the heterotopic bone around the affected hip(s) were studied by serial alkaline phosphatase determinations and radiographic examinations. Radionuclide bone scans using 99m Technetium diphosphonate were made in all patients. Treatment consisted of maintaining range of motion. This appears to be a self-limiting process as maturation occurs. Surgery was not necessary in this group. In patients with mature deposits, wedge and segmental resection of the extraosseous bone was necessary to regain enough hip flexion for the patinets to sit. This was followed by vigorous joint ranging. After one year, average range of recovered flexion was 60 degrees.