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Dr. Eliseo Mora Sánchez
2023-05-09 |
This article addresses hip dislocation that results from a traumatic injury.
When there is a hip dislocation, the femoral head is pushed either backward out of the socket, or forward.
Posterior dislocation. In approximately 90% of hip dislocation patients, the femur is pushed out of the socket in a backward direction. This is called a posterior dislocation. A posterior dislocation leaves the lower leg in a fixed position, with the knee and foot rotated in toward the middle of the body.
Anterior dislocation. When the femur slips out of its socket in a forward direction, the hip will be bent only slightly, and the knee and foot will rotate out and away from the middle of the body.
When the hip dislocates, the ligaments, labrum, muscles, and other soft tissues holding the bones in place are often damaged, as well. The nerves around the hip may also be injured.
Cause
Motor vehicle collisions are the most common cause of traumatic hip dislocations. The dislocation often occurs when the knee hits the dashboard in a collision. This force drives the thigh backwards, which drives the ball head of the femur out of the hip socket. Wearing a seatbelt can greatly reduce your risk of hip dislocation during a collision.
A fall from a significant height (such as from a ladder) or an industrial accident can also generate enough force to dislocate a hip.
While far less common, hip dislocations can result from a collision while playing a sport, like football or hockey.
Symptoms
A hip dislocation is very painful. Patients are unable to move the leg, and, if there is nerve damage, they may not have any feeling in the foot or ankle area.
Treatment
Reduction Procedures
If there are no other injuries, you will receive an anesthetic or a sedative, and an orthopaedic doctor will manipulate the bones back into their proper position. This is called a reduction.
In some cases, the reduction must be done in the operating room with anesthesia.
Following reduction, the surgeon will request another set of X-rays, and possibly a computed tomography (CT) scan, to make sure the bones are in the proper position.
Surgical Treatment
Surgical treatment may be required if there are fractures associated with the dislocation, or if the hip is unstable even after reduction.
The goals of surgery are to restore hip joint stability and to restore the cartilage surfaces to their normal positions. Typically, this requires a large incision, and the surgery may result in a lot of blood loss.
Patients may require a blood transfusion during or after this surgery.
Complications
A hip dislocation can have long-term consequences, particularly if there are associated fractures.
- Nerve injury. As the femur is pushed out of the socket, particularly in posterior dislocations, it can crush and stretch nerves in the hip. The sciatic nerve, which extends from the lower back down the back of the legs, is the nerve most commonly affected. Injury to the sciatic nerve may cause weakness in the lower leg and affect the ability to move the knee, ankle and foot normally. Sciatic nerve injury occurs in approximately 10% of hip dislocation patients. The majority of these patients will experience some nerve recovery.
- Osteonecrosis. As the femur is pushed out of the socket, it can tear blood vessels. When blood supply to the bone is lost, the bone can die, resulting in osteonecrosis (also called avascular necrosis). This is a painful condition that can ultimately lead to the destruction of the hip joint, and arthritis.
- Arthritis. The protective cartilage covering the bone may also be damaged, which increases the risk of developing arthritis in the joint. Arthritis can eventually lead to the need for other procedures, like a total hip replacement.
Recovery
It takes time — sometimes 2 to 3 months — for the hip to heal after a dislocation. The rehabilitation time may be longer if there are additional fractures. The doctor may recommend limiting hip motion for several weeks to protect the hip from dislocating again. Physical therapy is often recommended during recovery.
Patients often begin walking with crutches within a short time. Walking aids, such as walkers, crutches, and, eventually, canes, help patients regain their mobility.
