The hip joint is made of a ‘ball’ (the head of the thigh bone) and a cup-shaped ‘socket’ (a pelvic bone called the acetabulum). Sometimes a traumatic injury, such as a road traffic accident, can push the ball out of the socket. This is known as a hip dislocation.
Some babies are born with a hip joint that dislocates more easily than normal. However, this article focuses only on adult hip dislocations that have been caused by an injury.
A hip dislocation is a medical emergency that needs an emergency procedure to push the head of the thigh bone (femur) back into the acetabulum.
In 90% of hip dislocations, the head of the thigh bone (femur) is pushed backwards by a strong blow to the bent knee and hip. This most commonly happens when a person’s knees hit the dashboard during a vehicular accident.
Other causes of hip dislocation include:
- a fall from a significant height, such as falling off a ladder
- industrial accidents
- playing a contact sport, such as football or rugby
Less commonly, a blow to the hip can dislocate the joint by pushing the head of the femur forwards.
An artificial hip joint can also dislocate, often without any significant trauma. Artificial hip dislocations tend to happen soon after hip replacement surgery because the muscles and ligaments that hold the hip joint in place have been weakened by the surgery.
Some adults have a hip socket that is more shallow than normal. This can increase their risk of recurrent hip dislocations later in life.
People with hip dislocations tend to have severe hip pain and are often unable to walk or move the injured leg.
Because a lot of force is needed to dislocate a hip, it is common to also injure the muscles, ligaments, blood vessels, nerves, and bones around the hip during a hip dislocation.
This can lead to other symptoms, which may include leg, ankle, and/or foot numbness due to nerve damage.
Most hips tend to dislocate backwards. If this happens, the affected leg may look shorter and turn inwards towards the other leg. More rarely, a hip can dislocate forwards, causing the leg to turn outwards.
A doctor may suspect a dislocated hip based on symptoms, mechanism of injury, medical history, and a hip examination.
An X-ray may be needed to confirm the diagnosis.
A CT scan may also be recommended if the doctor treating the dislocation cannot push the femoral head back into the hip socket.
A hip dislocation is an emergency that needs to be treated quickly to prevent permanent damage to the hip bones. However, never move a person with a suspected hip dislocation. Instead, call for an ambulance to take them to the nearest hospital.
A hip dislocation is a serious condition that needs an emergency manoeuvre (closed reduction) to put the femoral head back into the hip socket and prevent bone tissue from dying. This procedure is usually done by a specialist (orthopaedic surgeon) under sedation or general anaesthetic.
Treatment for a dislocated hip will usually also include pain relief and the treatment of other injuries, such as blood loss.
Surgery may be needed if:
- small fragments of tissue or bone block the femoral head from going back into the socket - these fragments can be removed during surgery
- the hip joint dislocates again after being pushed back into place
- the hip or thigh bones are broken
Once the hip joint has been put back together, an X-ray and/or CT scan may be performed to make sure the bones are in the correct position.
Even with prompt and successful treatment, it can take around two to three months for a dislocated hip to heal.
Using crutches (on advice from your doctor) can help those with a dislocated hip to start walking soon after treatment.
A physiotherapist can also help with strengthening the hip muscles, which can assist the recovery process.
Hip dislocations can have long-term complications, which may include:
- an increased risk of developing osteoarthritis of the hip - the cartilage that covers and protects the hip bones can be damaged by a dislocation. This may increase the risk of developing arthritis in the joint
- recurrent hip dislocations
- avascular necrosis of the hip
- nerve damage
- damage to blood vessels
- complications of not being able to move around after surgery, such as blood clots
To find answers to any other health questions you might have, visit our Health A-Z.