Hip Dislocation Management in the ED

Updated: Jan 07, 2022
  • Author: Stephen R McMillan, MD; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Practice Essentials

Traumatic dislocations of the hip are an orthopedic emergency. Although the diagnosis of common posterior hip dislocation is often straightforward, emergent diagnosis and reduction of the dislocation, especially in light of the multiply injured trauma patient, can be challenging. High-energy blunt force trauma is the most common cause, although prosthetic hip joints may dislocate with much less force. Multiple studies have shown that timely reduction plays a significant role in reducing later complications and associated comorbidity. As a result, routine screening for this injury has been adopted as part of the evaluation of trauma patients. [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Congenital dislocation of the hip also occurs and is termed developmental dysplasia of the hip (DDH). The annual incidence of DDH is approximately 2-4 cases per 1000 births; approximately 80-85% of affected individuals are girls. Routine screening for DDH includes the Barlow and Ortolani tests, with additional testing such as ultrasound for cases prompting concern.

The American College of Radiology published the following guidelines for DDH [11] :

  • Imaging is not recommended for the initial imaging of children younger than 4 wk with an equivocal physical examination or risk factors shown for DDH.
  • Ultrasonography (US) of the hips is usually appropriate for the initial imaging of children between the ages of 4 wk and 4 mo with an equivocal physical examination or risk factors shown for DDH.
  • US of the hips is usually appropriate for the initial imaging of children younger than 4 mo with physical findings of DDH at initial imaging.
  • Radiograph of the pelvis is usually appropriate for the initial imaging of children 4-6 mo of age with a concern for DDH at initial imaging.
  • Radiograph of the pelvis is usually appropriate for the initial imaging of children older than 6 mo with a concern for DDH.
  • US of the hips is usually appropriate for children younger than 6 mo with a known diagnosis of DDH during nonoperative surveillance imaging in harness.

A high index of suspicion for hip dislocation must be present whenever a patient who is involved in a major trauma such as a motor vehicle accident, a significant fall, or a sports-related injury is assessed.

Patients with a hip dislocation will be in severe pain. They may describe pain in the lower extremities, back pain, or pain in pelvic areas. Patients have difficulty moving the lower extremity on the affected side and may report numbness or paresthesias. Frequently, patients are victims of multiple trauma and may not pinpoint hip pain as a result of altered mental status or distracting injuries. Patients with a total hip replacement may present differently.

A proper neurovascular examination should be performed. If a neurovascular deficit exists, the need to reduce the dislocation is more urgent. Appropriate analgesia should be provided. If hemodynamic status permits, intravenous narcotics are usually indicated. Radiographs to detect hip pathology should be obtained. Computed tomography (CT) is an accurate test for diagnosing hip injuries except in patients with prosthetic hips; streak artifact obscures the image in these cases. Information obtained by CT can be used for emergency treatment and for long-term prognosis and management. 

Usually, 1 person applies traction and 1 or 2 people supply countertraction. A nurse or another physician provides sedation. More than 3 attempts at closed reduction in the emergency department (ED) is not recommended. 

Hip dislocation has been noted to be one of the most common complications of total hip arthroplasty. [7]



The hip is a modified ball-and-socket joint. The femoral head is situated deep within the acetabular socket, which is further enhanced by a cartilaginous labrum. The hip is bolstered by a fibrous joint capsule, the ischiofemoral ligament, and many strong muscles of the upper thigh and gluteal region. Because of this anatomic configuration, the hip is stable, as shown in the image below.

A normal anteroposterior (AP) pelvis radiograph. A normal anteroposterior (AP) pelvis radiograph.

Subsequently, a large force is required to dislocate the joint. Because a high-force mechanism is required, other life-threatening injuries and fractures are common.

Motor vehicle crashes account for two thirds of traumatic hip dislocations, but falls from a height are also a significant cause, whereas sports injuries are a less common cause.

Hip dislocations can be divided into simple and complex, with the latter having associated fractures. One study suggests that complex dislocations are associated with poorer functional and radiologic outcomes than simple dislocations. Researchers found a strong association between intra-articular fragments and osteoarthritis, so surgical fragment removal could be considered in these cases. [12]

The relationship of the femoral head to the acetabulum is used to classify the dislocation. The 3 main patterns are posterior, anterior, and central.

Posterior dislocation

Posterior dislocations constitute approximately 80-90% of hip dislocations caused by motor vehicle accidents. The femoral head is situated posterior to the acetabulum. During a motor vehicle crash, force is transmitted to the flexed hip in 1 of 2 ways. During rapid deceleration, the knees strike the dashboard and transmit force through the femur to the hip. If the leg is extended and the knee is locked, force can be transmitted from the floorboard though the entire lower and upper leg to the hip joint.

In evaluating posterior hip (femur) dislocation, the first question an examiner should ask is whether the patient has a native hip or a prosthetic hip joint, as the clinical approach varies significantly. Additionally, it is paramount to evaluate for associated injuries such as fractures, as this will also drastically alter management. [13]

(A posterior dislocation is shown in the image below.)

Right posterior hip dislocation in a young woman f Right posterior hip dislocation in a young woman following a high-speed motor vehicle collision (MVC).

Anterior dislocation

The femoral head is situated anterior to the acetabulum. An anterior dislocation is most commonly caused by a hyperextension force against an abducted leg that levers the femoral head out of the acetabulum. Less commonly, an anterior force against the posterior femoral neck or head can produce this dislocation pattern.

Anterior hip dislocations have been reported to account for approximately 5-10% of all hip dislocations. Of all anterior hip dislocations, inferior or obturator dislocations are more common, constituting approximately 70% of all anterior dislocations. Risk factors for closed reduction of anterior hip dislocation include preexisting osteopenia on plain films, age greater than 65 years, and radiographic femoral head impingement on the surrounding bony pelvis. In one study, the need for closed reduction of both anterior and posterior hip dislocations was noted to be urgent; this procedure should occur within 6 hours after the time of dislocation. [7]

Central dislocation

A central dislocation is always a fracture-dislocation. As shown in the image below, the femoral head lies medial to a fractured acetabulum. This is caused by a lateral force against an adducted femur, as is commonly seen in side-impact motor vehicle collisions.

(A central fracture-dislocation is shown in the image below.)

Fracture-dislocation of the right hip. The bony fr Fracture-dislocation of the right hip. The bony fragments are likely part of the acetabulum.


Posterior hip dislocations are more common than anterior ones and account for almost 90% of hip dislocations. Their frequency has decreased with increased use of seat belts and air bags. Anterior dislocations and central fracture-dislocations account for less than 10% of hip dislocations.

Most studies have found that the incidence of dislocation after total hip arthroplasty (THA) is approximately 2-5%, with almost three quarters of these dislocations occurring in the first 6 weeks after surgery. [14]

Claims data for a large sample from a comprehensive health database in Taiwan illustrate several points regarding the epidemiology of hip dislocation [15] :

  • The hip was the most commonly dislocated joint of the lower extremity, with an incidence of 5.2%.

  • Closed reduction was achieved for more than 74% of the dislocations.

  • The incidence of recurrent dislocation was greater than 12%.

Another report indicates that the incidence of traumatic hip dislocation may be increasing due to larger numbers of high-speed motor vehicle accidents [16] —a phenomenon that may be repeated globally as larger populations gain access to motor vehicles.

Hip dislocation is more common among young males than among others because this injury is associated with risk-taking behavior.

In a study of sports-related hip injuries based on the sex and age of patients, the main diagnoses for males were labral tear (23.1%), avulsion fracture (11.5%), slipped capital femoral epiphysis (11.5%), dislocation (7.7%), and tendinitis (7.7%); and the main diagnoses for females were labral tear (59.0%), tendinitis (14.8%), snapping hip syndrome (6.6%), strain (4.9%), and bursitis (4.9%). The increase in hip injuries with advancing age was significantly greater among female than male athletes. [17]

Hip dislocation resulting from traumatic injuries (especially motor vehicle accidents) is more common in those younger than 35 years than in older people, whereas hip dislocation from a fall is more common in those older than 65 years.


Hip dislocation is a marker for a high-force mechanism. Most mortality is the result of associated injuries. Life-threatening injuries to the pelvis, abdomen, chest, and head should be specifically sought out.

Long-term disability after hip dislocation is a significant risk. Up to 50% of patients will have limited use or chronic pain as a result of hip dislocation. Prognosis becomes worse with delayed diagnosis and management. Complications include deep venous thrombosis (DVT), sciatic nerve injury, avascular necrosis (AVN), vascular injury, recurrent dislocation, arthritis, and chronic pain.

Local venous injury and prolonged immobilization associated with hip dislocation lead to a significant incidence of deep venous thrombosis and potentially lethal pulmonary embolus in affected patients. If no contraindications are known, patients should receive DVT prophylaxis as part of the hospital and rehabilitation treatment.

Sciatic nerve injury is common, reportedly occurring in up to 19% of patients. The femoral head or bony fragments can stretch or tear the nerve as it passes posteriorly. Neurapraxia is generally transient or minor. Full recovery or recovery with only minor neurologic effects can be expected for most patients. Performing and documenting a brief neurologic examination before and after relocation is imperative.

Avascular necrosis of the femoral head (AVN) occurs in 2-17% of patients. This can occur with pure dislocation but is more common with fracture-dislocation of the femoral head. Numerous studies suggest that risk of AVN rises in proportion to time to relocation. In other words, the longer it takes to relocate a hip, the higher is the risk of AVN. Early relocation of a hip can make the difference between a healthy joint and a chronically disabled joint.

Vascular compromise is rare. With anterior dislocation, the femoral artery is at risk. Pulses and perfusion should be checked and documented before and after reduction. If a patient has vascular compromise, reducing the hip should not be delayed. If a patient has a persistent or new-onset perfusion deficit, open reduction and consultation with a vascular surgeon may be indicated.

Recurrent hip dislocation is uncommon compared to recurrent shoulder dislocation. Risk factors for recurrent hip dislocation include large capsular defects, intra-articular fragments, or a prosthetic hip.

Posttraumatic arthritis is the most frequent long-term complication following hip dislocation. It occurs in up to 16% of affected individuals and is often associated with lifelong gait disturbances and chronic pain. If an associated acetabular fracture is present, the incidence of traumatic arthritis can be as high as 80%.

Traumatic dislocation is accompanied by a variety of intra-articular hip joint pathologies. Managing posterior acetabular rim fracture after traumatic posterior hip dislocation by using arthroscopic reduction and fixation with anchors is a safe and minimally invasive option and delays the progression of traumatic osteoarthritis. [18]



The prognosis of the patient with a hip dislocation varies with type of dislocation, associated fractures of the femoral head or acetabulum, and the presence of other injuries. Overall, 50-93% of patients have good to excellent results.

The principal determinants of a poor prognosis are as follows:

  • AVN occurs in 4-21.8% of patients in some reviews, and in 8-13% in others. The incidence is increased with delay in reduction beyond 6 hours and with open reduction. The severity of AVN is increased in patients who undergo early weight bearing. AVN is a serious complication that usually requires replacement with a prosthetic hip.

  • Severe osteoarthritis occurs in at least 10% of patients and is more common among older patients. This seems to be an increased incidence compared to populations of a similar age without hip dislocation; some authors have found the incidence to range from 30 to 71% after open reduction.

  • Injury to the femoral or sciatic nerve usually consists of neurapraxia; eventual recovery of function can be expected in these cases. Permanent injury to these nerves can result in disabling deficits. If the patient has a neurologic deficit, surgery usually is not indicated. Electromyography can be useful in determining prognosis.

  • Recurrent dislocation is a complication if supporting ligaments have been disrupted.