Hip dislocations occur when the femur slips out of place in the hip socket. Great force typically causes this injury, but it can result from an innocent activity, such as tying a shoe, if a person has had hip replacement surgery.

A hip dislocation is a medical emergency because it can affect a person’s blood flow and nerve communication. Without prompt emergency treatment, it can cause permanent complications.

This article will cover hip dislocation, including possible causes and treatments.

Screen capture (print) of live x-ray (fluoroscopy of dislocated (luxated) total hip arthroplasty (or replacement). The cup (or socket) in the acetabulum is made of a plastic material (fixed to the bone by cement). The stem and head (one piece) is made steel.Share on Pinterest
Image credit: silkfactory/Getty Images

A 2020 study suggests that motor vehicle accidents are the most common cause of hip dislocations. The injury usually requires significant force, which can also occur due to a high fall, such as from a ladder or window.

Because of the force required to cause a hip dislocation, a person often has another significant injury, such as a fracture.

A person who has had a hip replacement is more likely to experience hip dislocation. Some of the causes that may contribute to this include:

  • attempting to stand after sitting on a short or low-to-the-ground chair
  • bending down at the waist
  • crossing the legs, either in a sitting or standing position
  • sleeping on the side

According to an article in The Bone & Joint Journal, a hip replacement is most likely to dislocate within 1 month after hip replacement surgery.

An estimated 90% of the time, a person will dislocate their hip posteriorly. The hip is a ball-and-socket joint where the ball head of the femur (top bone of the leg) connects into the acetabulum (the socket where the femur fits).

When the hip displaces posteriorly, the ball of the femur moves toward the buttocks. When the hip displaces anteriorly, the ball of the femur moves toward the front of the body.

Causes in children

Children can experience hip dislocations due to congenital conditions, which a doctor will likely detect from routine prenatal screening.

This may include developmental hip dysplasia, where the hip joint does not form properly. Other causes include spastic hip disease, which is sometimes due to underlying medical conditions, such as cerebral palsy or neuromuscular disorders.

Young, adult males are most likely to experience an accident-related hip dislocation. As motor vehicle accidents are a common cause of hip dislocations, people should take precautions, such as wearing a seatbelt.

Having a hip replacement can also increase the risk a person will experience a hip dislocation.

Hip dislocations are very painful when they occur. As well as hip pain, a person may experience:

  • inability to move the leg
  • a leg that appears to turn inward or outward
  • a leg that seems to be slightly shorter than the other
  • problems moving the leg
  • loss of sensation in the foot or ankle

If a person thinks they may have dislocated their hip, they should seek emergency medical treatment.

Often, a doctor can identify a hip dislocation by physically examining the leg.

However, a doctor will usually order imaging studies to determine if there are other fractures or injuries they cannot identify with a physical exam. Examples of imaging studies include a CT scan.

It is essential to seek treatment for a hip dislocation within 6 hours of the injury to avoid permanent complications.

A hip displacement can affect blood flow to the leg and can damage the nerves. If a person does not have any fractures in the hip or leg, a doctor will likely carry out a closed reduction as the initial treatment method. A closed reduction involves carefully applying force to return the hip to its socket.

The closed reduction takes place in the emergency room, and the surgeon will first sedate the person, which means giving them medication to relieve pain and reduce muscle tension.

Closed reductions are often successful, but if the procedure does not work, a doctor may perform open reduction and internal fixation surgery. This involves removing any excess tissues or bone fragments and re-positioning the bones.

If a person has a hip replacement, a doctor may have to revise the replacement and potentially replace the implant. One option is to replace the area around the hip socket with a constrained liner. This special liner helps to reduce the likelihood the hip will dislocate again.

Treatment in infants

Children, especially infants, are also vulnerable to hip dislocation.

A doctor may recommend surgery. According to an article in the Journal of Pediatric Orthopaedics, surgery has a 90% success rate in treating or preventing hip dislocations in infants. Different surgical approaches exist, but all aim to stabilize the hip joint.

It may take up to 2–3 months for the hip to heal after a dislocation. This may take even longer if a person has other injuries, such as fractures.

The doctor will likely recommend that a person limits hip motion for several weeks. A person may use walking aids, such as crutches, walkers, or canes, to assist with walking.

If a person requires surgery, they may need several months and physical therapy to recover and rehabilitate. A doctor will give specific instructions on what exercises a person can do and what they should avoid.

Often, hip dislocations occur as a result of accidents. Practicing safety techniques, such as wearing a seatbelt in the car and using ladders safely, can help.

A person who has had a hip replacement or undergone other surgical procedures to correct traumatic fractures should follow a doctor’s orders about how much activity they can do post-surgery. This can reduce the likelihood a person’s hip will dislocate.

Hip dislocation can be extremely painful, and it is essential to seek emergency treatment and follow a doctor’s advice to enhance recovery and prevent long-term complications.