Sat., 10/16/10 Pelvis & Spine, Paper #82, 4:05 pm OTA-2010
Adaptive Prophylaxis Against Heterotopic Ossification Based on Body Habitus
Waleed F. Mourad, MD1; Satya Packianathan, MD1; Walid Waked, MD2;
Rania A. Shourbaji, BS3; Zhen Zhang, MS1; Majid A. Khan, MD1;
Matt L. Graves, MD1; George V. Russell, MD1;
1University of Mississippi Medical Center, Jackson, Mississippi, USA;
2Yale University School of Medicine, New Haven, Connecticut, USA
3Jackson State University, Jackson, Mississippi, USA
Purpose: Our objective was to retrospectively analyze the impact of differences in body habitus by using the World Health Organization criteria for body mass index (BMI) as a surrogate marker for risk of heterotopic ossification (HO) in patients who underwent open reduction and internal fixation (ORIF) for traumatic acetabular fractures followed by radiation therapy (XRT) ± indomethacin.
Methods: This is a single-institution retrospective analysis of medical records and radiographs of 395 patients with traumatic acetabular fractures. All patients were treated with ORIF followed by XRT ± indomethacin. All patients received postoperative XRT within 72 hours; 700 cGy was prescribed in a single fraction with fields that included the soft tissues around the proximal femur and acetabulum without bone shielding. The patients were separated into 4 groups based on their BMI: underweight group (BMI<18.5), normal weight group (BMI 18.5-24.9), overweight group (BMI 25-29.9), and obese group (BMI ≥30). HO was assessed during scheduled follow-up with standard radiographs. The end point of this study was to evaluate the efficacy of XRT ± indomethacin in preventing HO in patients with different BMIs.
Results: Analysis of BMI showed an increasing incidence of HO with increasing BMI: BMI <18.5, 0 of 6 patients (0%); BMI 18.5 to 24.9, 6 of 105 (5.7%); BMI 25 to 29.9, 22 of 117 (18.8%); and BMI ≥30, 51 of 167 (30.5%). A logistic regression analysis showed that the correlation between odds of HO and BMI is significant (P < 0.0001). As the BMI increases, the risk of HO and Brooker class 3 and/or 4 HO increases. On average, there appears to be a 10% increase in the odds of developing HO with each unit increase in BMI. The 95% confidence interval for the odds ratio is 1.06 to 1.14. The χ2 square test shows no significant difference among all other factors and HO (race, XRT ± indomethacin, gender, causes and types of fracture, and surgical exposures).
Conclusion: Despite similar surgical treatment and prophylactic measures (XRT ± indomethacin), the risk of HO significantly increases in patients with higher BMI after traumatic acetabular fractures. Modifications such as increased radiation dose or fractionated radiation treatment need to be investigated in clinical trials.
Alphabetical Disclosure Listing (292K PDF)
• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.