What strategy helps prevent heterotopic ossification after hip surgery?

• A. NSAID prophylaxis
• B. Radiotherapy in select high-risk cases
• C. NSAID prophylaxis and radiotherapy in select high-risk cases
• D. NSAID prophylaxis; radiotherapy in select high-risk cases

Answer: (D)

Heterotopic ossification after hip surgery is driven by an inflammatory cascade and early osteoprogenitor cell activity, so preventing it focuses on two fronts: damping inflammation and inhibiting abnormal bone-forming cells. Nonsteroidal anti-inflammatory drugs reduce prostaglandin-mediated inflammation after surgery, which lowers the chance that soft tissues will ossify abnormally. In patients who are at higher risk for HO, adding radiotherapy soon after the operation further suppresses HO by inhibiting the proliferation and differentiation of mesenchymal cells into bone-forming osteoblasts. Because NSAIDs provide broad protection and radiotherapy adds extra protection only in select high-risk individuals, the best overall strategy is to use NSAID prophylaxis for all patients and reserve radiotherapy for those high-risk cases.