Hip Dislocation and Subluxation

Causes, Treatments, and Complications

A hip dislocation is a very unusual injury that is most often the result of severe trauma. The most common causes of a hip dislocation include motor vehicle collisions, falls from a height, and sometimes catastrophic sports injuries.

People who sustain this injury will have severe hip pain, difficulty moving, and inability to bear weight on the extremity. The leg will be in an abnormal position as a result of the dislocation, most often with the leg shortened and rotated.

Hip dislocations can also occur as a complication of hip replacement surgery. Because an artificial hip replacement is different from a normal hip joint, dislocation after joint replacement is a possible risk of surgery.

According to a 2014 study from Germany, around 2 percent of people will sustain a hip dislocation within a year of a total hip replacement. Fortunately, newer prosthetics and surgical techniques are making this a far less common occurrence.

How the Hip Joint Works

The hip joint is a ball-and-socket joint. The socket of the hip joint is a deep cup of bone that is part of the pelvis (called the acetabulum). The ball is the top of the thigh bone (the femur) -- the name of the hip joint is the femoroacetabular joint. The major reason hip dislocations are so unusual, is that the ball is held deeply within the hip socket. Unlike the shoulder joint, where the ball is sitting loosely on the socket, hip dislocations are uncommon, whereas shoulder dislocations are very common.

In addition to the bone anatomy of the hip that creates a stable joint, the body also has strong ligaments, many muscles, and tendons that also contribute to the stability of the hip joint. In order for a hip dislocation to occur, significant force must be applied to the joint. People who feel a snapping sensation of the hip seldom have a dislocation of the joint; these conditions are known as snapping hip syndrome.

Hip Dislocation

When a hip dislocation does occur, there has to be damage to the structures that hold the ball in the socket. Common injuries that occur when a hip dislocation happens include fractures of the bone surrounding the hip, tears in the labrum and ligaments of the hip, and cartilage damage of the joint. In addition, injury to blood vessels that nourish the bone can lead to a condition called avascular necrosis (also called osteonecrosis of the hip).

People who sustain a hip dislocation have a very high risk of developing arthritis of the joint over the months and years that follow the injury and are at higher risk for needing a hip replacement later in their life. The extent of cartilage damage will ultimately determine the likelihood of developing future problems within the joint.

Treatment Options

The most important treatment of a dislocated hip is to properly position the ball back in the socket, called a joint reduction. In order to reposition the hip joint, the patient will require general anesthesia. Unlike a shoulder dislocation that many patients, especially those who have had repeat shoulder dislocations, can reposition on their own, a hip dislocation usually requires significant force to reposition.

According to review from NYU Langone Medical Center, the best results are achieved if the reduction is performed within six hours of the dislocation, either as an open surgery or an arthroscopic procedure using keyhole incisions.

Once the ball is back within the socket, your doctor will evaluate for other injuries, including injury to the bone, cartilage, and ligaments. Depending on the injuries that have occurred, further treatment may be necessary. Broken bones may need to be repaired in order to keep the ball within the socket, and damaged cartilage may have to be removed from within the joint.

Hip arthroscopy is becoming more commonly used as a tool to ensure the joint is as healthy as possible following this type of injury.

In addition, the development of early arthritis of the hip is very common following the type of trauma to the hip joint. Therefore, many patients who have a hip dislocation ultimately require hip replacement surgery.

A hip replacement surgery is performed to replace the ball and socket of the damaged hip joint. Hip replacement surgery is among the most common, and most successful orthopedic surgeries, but it is a major surgical procedure that is not without its risk.

This not only includes infection and aseptic loosening (the loosening of the joint without infection) but the very condition that may have led to the surgery in the first place: a hip dislocation.

The same German study concluded that as many as 17.7 percent of total hip replacements are attributed to dislocation. On the flip side, 28 percent of those who undergo revision surgery will experience a dislocation.

Despite these statistics, most people who undergo hip replacement surgery are able to resume a normal, active lifestyle without significant discomfort from their hip joint.

Hip Subluxation

A related injury is called a hip subluxation. A joint subluxation is another way of describing what people often call a partial dislocation. In the case of the hip joint, it means the ball started to come out of the socket but did not come fully out or dislocate.

People with a hip subluxation may have many of the same complications as those who sustain a hip dislocation. Over time, these individuals are just a liable to develop hip labral tears, osteonecrosis, and hip arthritis.

A hip subluxation was the injury that ended the career of football star Bo Jackson.

A Word From Verywell

A hip dislocation or subluxation is a potentially devastating injury that can lead to both short-term and long-term problems with the hip joint. People who sustained a hip dislocation typically require general anesthesia in order for the hip joint to be repositioned back in place.

After a hip dislocation, it is important to ensure the joint is stable and there were no other injuries to the surrounding bone. If there were, additional surgical intervention may be necessary.

People who sustained these injuries are at high risk for developing complications such as osteonecrosis and arthritis of the hip joint. Ultimately, hip replacement may become necessary if there was long-term damage to the hip joint.

Is It Time for a Hip Replacement?
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