Current Concepts in Neurogenic Heterotopic Ossification

Heterotopic ossification (HO) is abnormal bone deposition, most commonly in the hip or elbow, that can significantly impair patients due to pain, stiffness, and contractures, which prevents them from carrying out activities of daily living. A traumatic brain (TBI) or spinal cord injury may prompt the formation of heterotopic ossification, creating so-called neurogenic heterotopic ossification (NHO). The pathophysiology of this condition is not fully understood, but probably involves a complex interplay between a biological scaffold of demineralized bone, CNS signaling, and local tissue signal mediators that often result from trauma. This environment is conducive to HO formation. Diagnosis relies on laboratory testing, plain radiographs, and advanced imaging such as triple phase bone scan or computed tomography scan. Treatment involves medical management with anti-inflammatory drugs, bisphosphonates, radiation therapy, or surgical excision, although outcomes are variable both in regards to prevention and treatment. A mainstay of treatment is physical therapy to maintain range of motion. This paper also presents a case study of a poly-traumatized patient with a TBI and multi-level spinal column injury who developed NHO after acetabular fixation.