Review Question - QID 947

Heterotopic ossification is the formation of bone outside of the skeleton - often occuring within skeletal muscles. Illustrations A and B are representative examples of heterotopic ossification around the elbow and following a total hip arthroplasty. Around the hip, heterotopic ossification is classified via the Brooker classification (Illustration C). It is caused by activation and proliferation of mesenchymal stem cells and is an active research area in trauma and rehabilitation. Prolonged ventilator time, brain injury, spinal cord injury, burns, neurologic compromise (measured via GCS), and amputation thru the zone of injury in a patient injured in a blast are all literature proven risk factors for development of heterotopic ossification.

Pape et al retrospectively studied heterotopic ossifications in patients with blunt multiple trauma with and without associated head injury. They evaluated two cohorts of patients at risk for development of heterotopic ossification and found prolonged ventilation times in multiply traumatized patients was associated with an increased risk of development of heterotopic ossification.