Background: Although infrequently reported in amputees previously,
heterotopic ossification has proven to be a common and problematic clinical
entity in our recent experience in the treatment of traumatic and
combat-related amputations related to Operation Enduring Freedom and Operation
Iraqi Freedom. The purpose of the present study was to report the prevalence
of and risk factors for heterotopic ossification following trauma-related
amputation as well as the preliminary results of operative excision.
Methods: We identified 330 patients with a total of 373 traumatic
and combat-related amputations who had been managed at our centers between
September 11, 2001 and November 30, 2005. We reviewed the medical records and
radiographs of 187 patients with 213 amputations who had adequate radiographic
follow-up. Additional analysis was performed for twenty-four patients with
twenty-five limbs that required excision of symptomatic lesions. The mechanism
and zone of injury, amputation level, timing of excision, use of prophylaxis
against recurrence, and other confounding variables were examined. Outcomes
were assessed by determining clinical and radiographic recurrence rates,
perioperative complications, preoperative and follow-up pain medication
requirements, and the ability to be fit with a functional prosthesis.
Results: Heterotopic ossification was present in 134 (63%) of 213
residual limbs, with twenty-five lesions requiring excision. A final
amputation level within the zone of injury was a risk factor for both the
development and the grade of heterotopic ossification (p < 0.05). A blast
mechanism was predictive of occurrence (p < 0.05) but did not correlate
with grade. All patients who had been managed with excision were tolerating
the prosthetic limb at an average of twelve months of follow-up. Twenty-three
limbs demonstrated no evidence of recurrence, and two limbs had development of
clinically asymptomatic, radiographically minimal recurrences. Six patients
experienced wound-related complications that required reoperation, and two
patients required subsequent minor revision surgery. There was a significant
decrease in the use of pain medication following surgery (p < 0.05).
Conclusions: Heterotopic ossification following trauma-related
amputation is more common than the literature would suggest, particularly
following amputations that are performed within the initial zone of injury and
those that are due to blast injuries. Many patients are asymptomatic or can be
successfully managed with modification of the prosthesis. For patients with
refractory symptoms, surgical excision is associated with low recurrence rates
and decreased medication requirements, with acceptable complication rates.
Level of Evidence: Prognostic Level II. See Instructions
to Authors for a complete description of levels of evidence.