The hip is a ball-and-socket joint, where the ball is the femoral head and the socket is the acetabulum.
How does a prosthetic hip dislocation happen?
Dislocation of a normal hip is pretty unusual. It takes a tremendous amount of force, usually a high-speed car accident. On the other hand, patients who have had hip replacement surgery can dislocate their artificial hips with minimal force, such as rolling out of bed, or getting out of a chair. These dislocations typically happen in the first four months after surgery, and most artificial hip dislocations are posterior.
How to diagnose a prosthetic hip dislocation
Physical signs of a prosthetic hip dislocation
Dislocation of the hip forces the femoral head of the prosthesis out of the acetabulum and behind it. As a result, there are four physical signs to look for:
- Patient’s affected leg appears shortened
- Leg is flexed at the knee
- Hip is internally rotated
- Hip is adducted
Diagnostic tests for a prosthetic hip dislocation
You can confirm the diagnosis with an x-ray. On the x-ray, the femoral head is displaced out of the socket. This is best seen in the lateral view.
Excellent work! You now know the basics for diagnosing a prosthetic hip dislocation.
- Hendey, GW and Avila, A. 2011. The Captain Morgan technique for the reduction of the dislocated hip. Ann Emerg Med. 58: 536–540. PMID: 21839540
- Roberts, J. 2019. “Management of common dislocations”. In: Roberts and Hedges’ Clinical Procedures in Emergency Medicine and Acute Care. 7th edition. Philadelphia: Elsevier.
- Roberts, J. 2019. “Otolaryngologic procedures”. In: Roberts and Hedges’ Clinical Procedures in Emergency Medicine and Acute Care. 7th edition. Philadelphia: Elsevier.