Posterior Hip Dislocation

Definition:

• Posterior hip dislocation: Displacement of the femoral head out of the acetabulum towards the posterior aspect of the pelvis.

Epidemiology:

• Represents approximately 90% of all hip dislocations.
• Often results from high-energy trauma such as road traffic accidents.

Clinical Presentation:

• Severe pain in the affected hip and inability to move the leg.
• Limb appears shortened, adducted, and internally rotated.
• Possible associated injuries, especially if trauma was the cause.

Investigations:

• X-ray of the pelvis: Anteroposterior (AP) and lateral views are standard for diagnosis.
• CT scan: To assess associated fractures or to guide treatment.

Management:

• Immediate closed reduction: Under sedation or general anaesthesia to reduce risk of avascular necrosis of the femoral head.
• Operative intervention if closed reduction fails or in the presence of associated fractures.
• Post-reduction X-ray to confirm the correct positioning of the femoral head within the acetabulum.
• Physiotherapy and mobilisation as soon as it is deemed safe.

Complications:

• Avascular necrosis of the femoral head: Due to disruption of its blood supply.
• Osteoarthritis: Secondary to joint trauma.
• Sciatic nerve injury: Due to its proximity to the hip joint.
• Recurrent dislocation.

Prognosis:

• Depends on the promptness of reduction, extent of injury, and associated injuries.
• Early reduction minimises the risk of complications.