Why must a posterior hip dislocation be reduced promptly (within about 6 hours)?

• A. To avoid avascular necrosis
• B. To prevent fracture
• C. To prevent nerve injury
• D. To prevent DVT

Answer: (A)

Prompt reduction of a posterior hip dislocation is essential because the femoral head’s blood supply can be severely compromised when the joint is dislocated. The longer the dislocation lasts, the higher the risk that the arterial inflow to the femoral head is interrupted enough to cause osteonecrosis (avascular necrosis). Reducing the hip within about six hours helps restore perfusion sooner, significantly lowering the chance of the femoral head dying and preserving hip function. While fractures, nerve injury, and DVT can accompany hip dislocations, the urgent timing is most closely linked to preventing avascular necrosis of the femoral head.