A hip dislocation is a serious injury where the femur is forced out of its acetabulum. While the hip joint is naturally very stable, this displacement necessitates immediate medical attention due to potential complications.
What is a Hip Dislocation?
The hip is a ball-and-socket joint. A hip dislocation occurs when the femoral head is pushed out of the acetabulum. This requires substantial force, as strong ligaments and muscles stabilize the joint.
There are two primary types of hip dislocations. A posterior dislocation, where the thigh bone is pushed backward, is the most common, accounting for approximately 85% to 90% of cases. Less frequently, an anterior dislocation occurs when the femoral head is forced forward. Both types severely disrupt the hip’s normal alignment and function.
How Hip Dislocations Occur
Hip dislocations most often result from high-energy trauma. Motor vehicle collisions are the most frequent cause, particularly when the knee impacts the dashboard during a crash. This impact drives the thigh bone backward, forcing the femoral head out of the hip socket in a posterior dislocation. Passengers who are unrestrained are at particularly high risk in such incidents.
Falls from significant heights or severe sports injuries also generate enough force to dislocate a hip. The position of the hip at the moment of impact influences the direction of the dislocation. For instance, a posterior dislocation often happens with the hip flexed, adducted, and internally rotated. While traumatic events are the primary cause, certain pre-existing conditions like hip dysplasia or previous hip replacement surgery can make dislocations occur with less force.
Recognizing and Responding to a Dislocation
A hip dislocation presents with severe pain and an inability to move the affected leg. The leg may appear visibly deformed, often shortened, and rotated inward for a posterior dislocation, or outward for an anterior dislocation. Swelling or bruising around the hip joint may also become apparent shortly after the injury.
Immediate medical attention is necessary for a suspected hip dislocation. It is important not to attempt to move the person or try to put the hip back into place. Instead, stabilize the injured leg as much as possible and contact emergency services. Medical professionals will use imaging, such as X-rays or CT scans, to confirm the diagnosis and assess for any associated injuries like fractures.
Recovery and Long-Term Outlook
The initial treatment for a hip dislocation involves repositioning the femoral head back into its socket, a process called reduction. This is performed under sedation or anesthesia. If there are no associated fractures, a closed reduction is attempted; otherwise, surgery may be required.
After the hip is reduced, a period of restricted movement and limited weight-bearing, often with crutches, follows. Physical therapy is important for regaining strength, flexibility, and range of motion. Full recovery can take two to three months, potentially longer if other injuries are present. Potential long-term concerns include avascular necrosis, where bone tissue dies due to disrupted blood supply, and sciatic nerve damage, which can cause weakness or numbness in the leg. The risk of developing arthritis in the joint also increases following a hip dislocation.