Background
Systematic review and meta-analysis. 12 RCTs, 1,208 patients undergoing total hip arthroplasty (THA) or surgery for acetabular fracture. Compared postoperative RT (single fraction or short course) vs NSAIDs (indomethacin) vs no prophylaxis for prevention of heterotopic ossification (HO). Aimed to determine the optimal prophylactic strategy for HO after hip surgery. Pakos EE et al, IJROBP 2004.
Interventions and follow up
Arm A: RT prophylaxis: 7–8 Gy single fraction (within 72 hours of surgery, most commonly 6–8 Gy × 1) to hip regio
Arm B: NSAIDs (indomethacin 75 mg/day × 3–6 weeks)
Primary endpoint: Rates of any HO (Brooker I–IV) and severe HO (Brooker III–IV) at 6–12 month
mFollow up: 12 month
Arm B: NSAIDs (indomethacin 75 mg/day × 3–6 weeks)
Primary endpoint: Rates of any HO (Brooker I–IV) and severe HO (Brooker III–IV) at 6–12 month
mFollow up: 12 month
Results
Arm C (comparison): No prophylaxis (historical controls)
Any HO (RT): 25% vs no prophylaxis 46% vs NSAIDs 28%
Severe HO (Brooker III–IV, RT): 5% vs no prophylaxis 20% vs NSAIDs 6%
RT vs NSAIDs: Equivalent efficacy — no significant difference (RR 0.92, P=.41)
Any HO (RT): 25% vs no prophylaxis 46% vs NSAIDs 28%
Severe HO (Brooker III–IV, RT): 5% vs no prophylaxis 20% vs NSAIDs 6%
RT vs NSAIDs: Equivalent efficacy — no significant difference (RR 0.92, P=.41)
Adverse events
Main adverse events: RT: local erythema (mild), theoretical secondary malignancy risk (estimated <0.05% lifetime). NSAIDs: GI toxicity, renal effects, platelet inhibition. RT preferred over NSAIDs in patients with GI contraindications, renal disease, or platelet dysfunction.
Conclusions
Single-fraction RT (7–8 Gy) and NSAIDs (indomethacin) are equally effective in preventing HO after THA. Both significantly reduce severe HO (Brooker III–IV) compared to no prophylaxis. RT is preferred when NSAIDs are contraindicated. The choice between RT and NSAIDs should be individualized based on patient risk factors.
Key Limitations
Key Limitations: Heterogeneous RCT population — different surgical procedures, RT doses, NSAID regimens. Follow-up duration variable (6–12 months). Functional outcomes (hip range of motion, patient-reported function) not consistently reported. Secondary malignancy risk from RT near genitalia in young patients not quantified in this analysis.
Clinical Context
HO prophylaxis is standard for high-risk THA (prior HO, DISH, ankylosing spondylitis, bilateral THA). Single-fraction RT 7 Gy within 24–72 hours post-surgery is the standard RT regimen. NSAIDs (indomethacin) for 3–6 weeks post-op are equally effective and more commonly used in the US. RT is preferred for patients with NSAID contraindications.
References