Radiation Therapy for Heterotopic Ossification Prophylaxis

Excerpt

Heterotopic ossification (HO) is the formation of mature lamellar bone in soft tissues where bone does not normally exist. HO is commonly seen following trauma or surgical intervention in periarticular soft tissue and is commonly associated with hip injury. The 3 primary causes can be grouped into traumatic, neurogenic, and genetic etiologies.

HO from trauma includes fractures, dislocations, and operative procedures such as open reduction-internal fixation (ORIF) or total hip arthroplasties (THA). The hip's most involved compartment is the abductor compartment. The elbow is the next most commonly involved joint following burns or elbow replacements.

Neurogenic causes include spinal trauma and head injuries and again occur around major joints. The relationship between neurohumoral factors and the development of HO is poorly understood but is centered around the stimulation of osteoblasts to lay down ectopic bone.

The last main etiology includes genetic disorders, such as fibrodysplasia ossificans progressiva, progressive osseous heteroplasia, and Albright hereditary osteodystrophy. These rare conditions lead to the development of HO early in life, resulting in debilitating morbidity.