Overview
what it is and why it mattersA hip dislocation is when the ball at the top of your femur gets forced out of the socket in your pelvis. Most of the time (about 90% of cases) the ball pops out the back, usually after a high-energy impact like a car accident, a sports collision, or a fall from height. The classic mechanism is a knee striking a dashboard and driving the hip backward. The opposite direction (out the front) is less common and happens when the leg is forced wide and rotated outward.
Hip dislocation is a true emergency. The arteries that supply blood to the ball of the hip run alongside the back of the joint capsule, and the longer the hip stays dislocated, the higher the risk those vessels are stretched or torn. After about 6 hours, the chance of the ball losing its blood supply (avascular necrosis) rises sharply. Up to half of dislocations come with associated fractures of the ball, the socket rim, or the neck of the femur.
Symptoms
what you may noticeAfter a posterior dislocation, the most common type, your leg looks obviously abnormal: shortened, rotated inward, and drawn toward the midline. The pain is immediate and severe, and you cannot move the hip at all. These injuries nearly always follow a major impact such as a car crash or a high-speed sports collision.
Numbness or tingling running down the back of the thigh and leg can signal that the sciatic nerve, which passes directly behind the hip joint, has been stretched or compressed by the dislocated ball. About 10 to 15% of posterior hip dislocations involve a sciatic nerve injury. Any associated fracture of the socket rim (acetabular fracture) or femoral head adds to the swelling and may trap bone fragments inside the joint.
Diagnosis
exam first, imaging secondA posterior hip dislocation is unmistakable: severe pain, the affected leg looks shorter than the other, rotated inward, and pulled toward the midline. A standard pelvis X-ray confirms the diagnosis. After the hip is put back into place, a CT scan is essential: it picks up associated fractures and any loose pieces of cartilage or bone trapped inside the joint. Your surgeon will also carefully check the function of the sciatic nerve, which runs right behind the joint and can be stretched or pinched in a posterior dislocation.
How We Treat It
first the hip goes back, then it healsCare for a hip dislocation happens in two stages. The first stage is urgent: get the ball back into the socket quickly, because every hour it stays out raises the risk to the joint's blood supply. The second stage is patient: protect the hip while the soft tissues around it heal, and watch over the following months for any sign that the blood supply was harmed. The steps below follow that order.
1
Closed reduction under sedation
The hip is put back into place as soon as possible, typically in the emergency department or operating room with sedation and muscle relaxation. Speed matters: every hour the hip stays out of joint raises the risk to the blood supply.
2
Protected weight-bearing
After the hip is reduced and confirmed stable, you'll go through a protected weight-bearing phase (crutches or a walker) while the joint capsule and soft tissues heal. Over months, your surgeon will track for any signs of avascular necrosis with periodic imaging.
Surgical Options
if non-operative care isn't enoughSurgery is needed when the hip can't be put back into place by manipulation alone, when associated fractures need to be fixed, or when loose pieces of bone or cartilage in the joint need to be removed.
Frequently Asked
questions we hear in clinicWhy is a hip dislocation an emergency?
The arteries that supply blood to the ball of the hip run alongside the back of the joint capsule. The longer the hip stays dislocated, the higher the risk those vessels are stretched or torn. After about 6 hours, the chance of the ball losing its blood supply (avascular necrosis) rises sharply, which is why the hip is put back into place as soon as possible.
Which way does the hip usually dislocate?
About 90% of the time the ball pops out the back (a posterior dislocation), usually after a high-energy impact like a car accident, a sports collision, or a fall from height. The classic mechanism is a knee striking a dashboard and driving the hip backward. The opposite direction, out the front, is less common and happens when the leg is forced wide and rotated outward.
How is the hip put back into place?
With a closed reduction: the hip is guided back into the socket, typically in the emergency department or operating room, using sedation and muscle relaxation. This is done as soon as possible because every hour the hip stays out of joint raises the risk to the blood supply.
Could the dislocation have injured a nerve?
It can. Numbness or tingling running down the back of the thigh and leg can signal that the sciatic nerve, which passes directly behind the hip joint, has been stretched or compressed by the dislocated ball. About 10 to 15% of posterior hip dislocations involve a sciatic nerve injury, so your surgeon carefully checks the nerve's function.
Will I need surgery?
Not always. Surgery is needed when the hip can't be put back into place by manipulation alone, when associated fractures need to be fixed, or when loose pieces of bone or cartilage in the joint need to be removed. Up to half of dislocations come with associated fractures of the ball, the socket rim, or the neck of the femur.
What happens after the hip is back in place?
Once the hip is reduced and confirmed stable, you go through a protected weight-bearing phase with crutches or a walker while the joint capsule and soft tissues heal. Over the following months, your surgeon tracks for any signs of avascular necrosis with periodic imaging.
Providers Who Treat Hip Dislocation
sports-medicine team
Further Reading
authoritative sourcesExternal patient-education references and related OSI pages for additional background: