Risk Factors in Hospitalized Patients With Burn Injuries for Developing Heterotopic Ossification-A Retrospective Analysis

The aims of this study were to identify the risk factors for developing heterotopic ossification in patients with burns injuries and, second, to review the outcomes associated with the treatment disodium etidronate. Patients with heterotopic ossification were identified using the burns unit computer database. The control group was the patients who were the next admission after admission of the patient who subsequently developed heterotopic ossification. Demographic and clinical data were collected. Univariate and multivariate techniques were used to identify risk factors for heterotopic ossification. We reviewed 337 patients admitted over a 5-year period and identified 19 patients with heterotopic ossification (5.6%). A further 19 burn injury patients were included as controls. Heterotopic ossification developed clinically and radiologically after a median time of 37 days (interquartile range [IQR], 30-40) and 49 days (IQR, 38-118), respectively. In univariate analysis, heterotopic ossification was associated with a greater %TBSA, inhalation injury, use of mechanical ventilation, number of surgical procedures, sepsis, and longer time to active movement. In a multivariate analysis that adjusted for severity of burn injury by means of the Belgian Outcome in Burn Injury score, time to active movement was recognized as an independent risk factor for heterotopic ossification (odds ratio 1.48, 95% confidence interval 1.09-2.01). Elevations in serum calcium concentrations were the only observed adverse effects for disodium etidonrate. This study has demonstrated that %TBSA, inhalation injury, and the need for ventilatory support and the use of multiple surgical procedures are predictive of the development of heterotopic ossification.