Does Postoperative Radiation Decrease Heterotopic Ossification After the Kocher-Langenbeck Approach for Acetabular Fracture?

BACKGROUND: Controversy regarding heterotopic ossification (HO) prophylaxis exists after Kocher-Langenbeck for treatment of acetabular fracture. Prophylaxis options include antiinflammatory oral medications, single-dose radiation therapy, and débridement of gluteus minimus muscle. Prior literature has suggested single-dose radiation therapy as the best prophylaxis to prevent HO formation. However, recent reports have emerged of radiation-induced sarcoma after radiotherapy for HO prophylaxis, which has led many surgeons to reconsider the risks and benefits of single-dose radiation therapy. We set out to determine if radiotherapy, in addition to standard débridement of gluteus minimus muscle, affected postoperative HO formation after a Kocher-Langenbeck approach for acetabular fracture. QUESTIONS/PURPOSES: (1) After the Kocher-Langenbeck approach and gluteus minimus débridement, is single-dose radiotherapy associated with a decreased risk of HO? (2) Does addition of single-dose radiotherapy prolong length of stay after a Kocher-Langenbeck approach and gluteus minimus débridement as compared with patients without radiotherapy?
METHODS: After institutional review board approval, all adult patients treated for acetabular fracture by a single surgeon with a Kocher-Langenbeck approach between August 2011 and October 2014 were identified (n = 60). Débridement of gluteus minimus muscle caudal to the superior gluteal bundle was standard in all patients. Radiotherapy was given with a single dose of 700 cGy within 72 hours of surgery from August 2011 until April 2013. Patients treated subsequently did not receive radiotherapy. Patients treated with indomethacin (n = 1) and with fewer than 10 weeks followup were excluded (n = 12) because several studies suggest that most HO that develops is visible by that point in time. Our study group totaled 46 patients with 24 in the radiotherapy and débridement group and 22 in the débridement group. Charts were reviewed to determine length of stay. Attending orthopaedic trauma surgeons who were blinded to the patient's treatment group graded all followup radiographs according to the Brooker system, and Classes III and IV HO were considered clinically important Fisher's exact test was used to analyze clinically significant differences HO between the two groups. Length of stay was compared using a t-test.
RESULTS: Single-dose radiotherapy is associated with a decreased risk of clinically important (Brooker III-IV) HO after a Kocher-Langenbeck approach and gluteus minimus débridement (radiotherapy: one of 24 [4%], no radiotherapy: seven of 22 [32%], relative risk: 0.131 [95% confidence interval {CI}, 0.018-0.981], p = 0.020). Addition of single-dose radiotherapy did not result in increased length of stay (radiotherapy: 12 ± 7.0 days; no radiotherapy: 11 ± 7.2 days; mean difference: 1.0 [95% CI, -3.2 to 5.2] days, p = 0.635).
CONCLUSIONS: Single-dose radiation in combination with gluteus minimus débridement decreases the risk of clinically important HO compared with gluteus minimus débridement alone after a Kocher-Langenbeck approach for acetabular fracture. No differences in length of stay were seen. Surgeons who chose not to use radiotherapy as a result of concern for future sarcoma may see higher rates of clinically significant HO after a Kocher-Langenbeck approach for acetabular fracture fixation. LEVEL OF EVIDENCE: Level III, therapeutic study.