The adult patient with neurogenic heterotopic ossification (HO) gives a history of progressive loss of range of motion (ROM) accompanied by pain or swelling in the involved area. Localized erythema along with warmth and low- to moderate-grade fever may also be present. Most pediatric patients present with decreased ROM but are less likely to have physical symptoms.
The average length of time reported between spinal cord injury and diagnosis of neurogenic HO in the adult population is 6 months, which is in contrast to 14 months after injury in the pediatric population. The use of 3-phase bone scanning to detect HO may result in a shorter average reporting time between injury and diagnosis.
Four clinical stages of HO in people with spinal cord injury were described by Nicholas in 1973.[8] Please see the figure below.