Hip dislocations are often associated with fractures of the acetabulum, ipsilateral femur, or knee, and can be anterior, posterior, or inferior. Ninety percent are posterior, resulting from significant forces exerted on a flexed hip and knee (eg, a passenger in a motor vehicle collision whose knees hit the dashboard). Anterior hip dislocations occur when there is forced external rotation of the extended hip, which forces the head out of the acetabulum, either by tearing the anterior capsule or by fracturing the anterior wall of the acetabulum.
Patients complain of severe hip pain and decreased range of motion. Posterior dislocations present with the extremity shortened, internally rotated, adducted, and flexed. With anterior dislocations, the leg is often abducted, externally rotated, and slightly flexed; however, this presentation can vary.
Management and Disposition
Treatment for dislocations is early closed reduction, often with conscious sedation, although ultrasound-guided femoral nerve blocks are an option. A neurovascular and radiographic evaluation should occur before and after reduction attempts. Since the muscles around the hip are so strong, a general anesthetic with complete paralysis may be required. Posterior dislocations are reduced using in-line traction with the hip and knee flexed to 90 degrees, followed by gentle internal to external rotation; several different techniques can be used for reduction: the Allis maneuver, the Bigelow maneuver, and the Captain Morgan technique. Anterior dislocations are reduced using strong in-line traction with the hip in neutral flexion extension or slight extension, slight adduction and internal rotation, followed by abduction.
Hip Dislocation. Typical patient appearance of a left posterior hip dislocation. Note internal rotation of the affected extremity (A). Radiograph (B). (Photo contributor: Cathleen M. Vossler, MD.)
Orthopedic consultation should be obtained as early as possible. These patients require admission, with frequent neurovascular evaluation. Hip replacements tend to dislocate more easily than native hips and usually require less energy for reduction. Radiographs should be done before and after reduction to evaluate for periprosthetic fractures.
Complications of posterior hip dislocations include sciatic nerve injury and avascular necrosis. Neurovascular complications of anterior hip dislocations are uncommon.
In the young patient, immediate reduction of a native hip is imperative and should be accomplished within 6 hours.
Allis Maneuver for Reduction of Posterior Hip Dislocation. (Reproduced with permission from Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 9th ed. New York, NY: McGraw Hill; 2020.)
The Bigelow Maneuver for Reduction of Posterior Hip Dislocation. (A...