KEY POINTS
- This retrospective 1:3 matched cohort study included 344 patients undergoing total hip arthroplasty: 86 received preoperative radiotherapy and 258 received postoperative non-steroidal anti-inflammatory drug prophylaxis. Matching used sex, cemented versus cementless fixation, and age within three years.
- Radiotherapy consisted of 7 Gy in one fraction, delivered 20–28 hours before surgery, substantially outside the guideline-supported four-hour preoperative window. The comparison group received diclofenac 50 mg twice daily for at least 14 days after surgery.
- Any radiographic heterotopic ossification developed in 18.6% of radiotherapy patients versus 22.5% with diclofenac. The matched analysis found no significant difference between strategies (OR 0.79, 95% CI 0.43–1.46; p=0.449).
- Clinically more substantial heterotopic ossification of Brooker grade ≥2 was also not significantly different (OR 0.77, 95% CI 0.33–1.80; p=0.541). Adjustment for age and radiographic follow-up duration did not materially alter either result.
- An exploratory sex-stratified analysis suggested lower heterotopic ossification rates with radiotherapy among men: 16.2% versus 33.3%, corresponding to an OR of 0.41. Among women, rates were 20.4% versus 14.3%, and no benefit was observed (OR 1.54); this potential interaction was exploratory rather than confirmatory.
- Follow-up radiographs were obtained a mean of approximately 825 days after surgery in the radiotherapy group and 922 days after surgery with diclofenac. Patients lacking imaging at least 362 days after arthroplasty were excluded.
- Radiotherapy was generally selected because non-steroidal anti-inflammatory drugs were contraindicated, leaving potential residual confounding despite matching. The wide confidence intervals also mean that clinically relevant inferiority or superiority cannot be excluded.
CLINICAL TAKEAWAY
Delivering 7 Gy on the day before hip arthroplasty may offer substantially greater logistical flexibility than the conventional four-hour window without an obvious loss of prophylactic efficacy. These data support further prospective evaluation, not immediate declaration that delayed preoperative radiotherapy is equivalent to diclofenac or guideline-timed treatment.
SOURCE
International Journal of Radiation Oncology, Biology, Physics