eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Dislocation, Hip

Edward T Tham, MD, Fellow in Emergency Ultrasound, Clinical Instructor, Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine
Christopher I Doty, MD, FACEP, FAAEM, Assistant Professor of Emergency Medicine, Residency Program Director, Department of Emergency Medicine, Kings County Hospital Center, State University of New York Downstate Medical Center

Updated: Dec 2, 2008

Introduction

Background

In general, hip dislocations can be classified into congenital and traumatic. The annual incidence of congenital hip dislocation is approximately 2-4 cases per 1000 births, and approximately 80-85% of the affected individuals are girls. Congenital hip dislocations are commonly the result of femoral head or acetabular dysplasia.  
 
The focus of this article is on traumatic hip dislocations. High-energy blunt force trauma is the most common cause. Dislocation of the hip joint is an orthopedic emergency. Without timely diagnosis and management, significant morbidity can result. 

Pathophysiology

The hip is a modified ball-socket joint. The femoral head is situated deep within the acetabular socket, which is further enhanced by a cartilaginous labrum. The hip is also 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. Subsequently, a large force is required to dislocate the joint. Since a high force mechanism is required, other life-threatening injuries and fractures are common.
 
Motor vehicle crashes (MVC) account for almost two thirds of traumatic hip dislocations. Falls from height and sports injuries are also common causes of hip dislocations.
 
The relationship of the femoral head to the acetabulum is used to classify hip dislocations. The 3 main patterns are posterior, anterior, and central.  

Posterior dislocation
 
Posterior dislocations compromise approximately 80-90% of hip dislocations caused by MVCs. The femoral head is situated posterior to the acetabulum. During a MVC, force is transmitted to the flexed hip in one of two ways. During rapid deceleration, the knees strike the dashboard and transmit the 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. 
 
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.
 
Central dislocation

A central dislocation is a fracture-dislocation where the femoral head lies medial to a fractured acetabulum. This is caused by a lateral force against an adducted femur seen in side impact MVCs.

Frequency

United States

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

The incidence of congenital hip dislocations is approximately 1 case per 500 population, which is equivalent to 0.20% or 544,000 people. Extrapolated data suggest that the prevalence of congenital hip dislocation is approximately 587,310.

International

Good extrapolated data about the incidence of congenital hip dislocations are available for many countries. The reader is referred to the References.

Mortality/Morbidity

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 dislocations 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. 

• The local venous injury and prolonged immobilization associated with hip dislocations lead to a significant incidence of deep venous thrombosis (DVT) and potentially lethal pulmonary embolus in affected patients.  If no contraindications exist, patients should receive DVT prophylaxis as part of the hospital and rehabilitation treatment.
• Sciatic nerve injury is common, up to 19% in one study. The femoral head or bony fragments can stretch or tear the nerve as it passes posterior. The neurapraxia is generally transient or minor. A full recovery or recovery with only minor neurological findings can be expected for most patients. Performing and documenting a brief neurological examination before and after relocation is imperative. 
• Avascular necrosis of the femoral head occurs in 2-17% of patients. This can occur with pure dislocations but is more common with fracture-dislocations of the femoral head. Numerous studies suggest that the risk of AVN rises proportional to the time to relocation. The longer it takes to relocate a hip, the higher 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 a rare. With anterior dislocations, 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, an 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 dislocation are 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 life-long gait disturbances and chronic pain. If an associated acetabular fracture is present, the incidence of traumatic arthritis is as high as 80%.

Race

Race is not a risk factor for hip dislocation.

Sex

Hip dislocations are more common in young males than in others because these injuries are associated with risk-taking behavior.

Age

Hip dislocations resulting from traumatic injuries (especially MVCs) are more common in those younger than 35 years than in older people. Hip dislocations resulting from falls are more common in those older than 65 years than in younger people.

Clinical

History

A high index of suspicion for hip dislocation must be present whenever evaluating a patient involved in a major trauma such as an MVC, significant fall, or an athletic injury.

• Patients with a hip dislocation will be in severe pain. They may complain of pain to the lower extremities, back, or pelvic areas. 
• Patients will have difficulty moving the lower extremity on the affected side and may complain of numbness or paresthesias. 
• Frequently, patients will be a victim of multiple trauma and may not pinpoint pain to the hip as a result of altered mental status or distracting injuries. 
• Patients with a total hip replacement may present differently (see Special Concerns).

Physical

As with any major trauma victim, assessment of the airway, breathing, and circulation are of primary importance. During the secondary survey, an examination of the pelvic girdle and hip are mandatory. Examination should consist of inspection, palpation, active/passive range of motion, and a neurovascular examination. 

Inspection

Isolated anterior and posterior dislocations have classic appearances. In practice, these appearances may be altered by the presence of fracture-dislocations or other bony abnormalities along the leg. 

• Posterior: The hip is flexed, internally rotated, and adducted.
• Anterior: The hip is minimally flexed, externally rotated and markedly abducted

Palpation

Palpate the pelvis and lower extremity for any gross bony deformities or step-offs.  In an anterior hip dislocation, the femoral head can occasionally be palpated. Large hematomas may signify vascular injury.
 
Range of motion

Patients with a hip dislocation have severely limited range of motion. Evaluate what the patient can do comfortably. Do not forcefully perform range of motion on a patient who cannot tolerate manipulation. Normal, painless range of motion virtually excludes hip dislocation. 
 
Neurovascular examination

Signs of sciatic nerve injury include the following:

• Loss of sensation in posterior leg and foot
• Loss of dorsiflexion (peroneal branch) or plantar flexion (tibial branch)
• Loss of deep tendon reflexes (DTRs) at the ankle

Signs of femoral nerve injury include the following:

• Loss of sensation over the thigh
• Weakness of the quadriceps
• Loss of DTRs at knee

Signs of vascular injury include the following:

• Hematoma 
• Loss of pulses 
• Pallor

Causes

High-speed motor vehicle collisions (MVCs) are by far the leading cause of hip dislocations. Falls from significant height and sports-related injury are also among the top causes.   

Differential Diagnoses

Abdominal Trauma, Blunt
Fractures, Femur
Fractures, Hip
Fractures, Pelvic
Legg-Calve-Perthes Disease
Pediatrics, Limp

Workup

Laboratory Studies

No specific laboratory studies are indicated for hip dislocation. Laboratory studies should focus on the overall trauma workup and/or preoperative testing. Type and crossmatching of blood products is generally the most useful. 

Imaging Studies

Radiography

A portable anteroposterior (AP) pelvis radiograph is often ordered as part of an initial trauma workup. The initial test should be a radiograph of the pelvis and hip. The presence of a hip dislocation can be subtle; however, a careful inspection of the AP pelvis radiograph should reveal most hip dislocations. Lateral views may further classify the type of dislocation. 

• Findings on an AP pelvis radiograph
  • The position of the femoral head relative to the acetabulum should be symmetrical. The joint space should be examined for bony fragments, widening, or evidence of an effusion. 
  • Both femoral heads should be roughly the same size. In a posterior dislocation, the femoral head may appear smaller than the contralateral side. This is because it is further away from the x-ray beam and is magnified less. The opposite is true of anterior dislocations.
  • The positions of the trochanters in relation to the femoral shaft may reveal abnormal rotation.
  • Shenton’s line is a smooth curved line defined by the obturator foramen and the femoral metaphysis. If this line is disrupted, a hip fracture, dislocation, or femoral neck fracture should be suspected.
  • A thorough inspection of the film for associated fractures must be conducted. 
  • If the AP pelvis film is nondiagnostic and a high index of suspicion exists, a lateral hip film, dedicated hip films, Judet views, or CT scan may be indicated.  

Computed tomography (CT) scan

A CT is an accurate test for diagnosing hip injuries except in patients with prosthetic hips where streak artifact obscures the image. A CT accurately delineates the type of dislocation as well as any accompanying fractures. CT scans of the pelvis are routinely obtained on major trauma patients. The information obtained by CT can be used in the emergency department and for long-term prognosis and management. If a CT scan is being performed to evaluate the abdomen and pelvis, the hip should be examined for pathology. However, a dedicated hip CT scan should not delay reduction. After the hip is reduced, a CT scan of the hip will provide valuable information to the orthopedist for further surgical or conservative management.

Magnetic resonance imaging (MRI)

MRI has a limited role in acute diagnosis and delineation of hip dislocations. Patients with multiple trauma are often unstable for MRI. It is time consuming and often unavailable. Once the patient is stabilized and the hip is reduced, MRI can provide valuable information about long-term management and prognosis.

Other Tests

• Radionucleotide scanning is a sensitive method that depicts early avascular necrosis (AVN).
• Radionuclide scanning is currently the criterion standard for diagnosis for AVN, though it is being replaced by MRI, which reveals greater anatomic detail and which appears to be equally sensitive.

Procedures

Reduction techniques are described as follows:

Allis method

The patient should be supine and under procedural sedation. The combined weight of the patient and physician may exceed the weight limit of the stretcher. It is generally unsafe for the physician to be standing on a stretcher. For these reasons, placing the patient on the floor rather than on the stretcher is often useful.

An assistant should stabilize the pelvis. The physician should initially be toward the patient’s feet, providing in-line traction. The physician should then gently flex the hip 60-90^o while maintaining in-line traction. At this point, the physician is standing directly above the patient’s hip, providing traction in-line with the deformity.

Gently adducting the hip can force the head of the femur laterally and help it clear the acetabular rim. Alternately, gentle lateral traction can be applied to the proximal femur.

Reduction can be confirmed by a click that is felt and may be heard as well. The patient should assume normal anatomical position.

Stimson method

This method is mechanically the same as the Allis method, but the positioning is opposite. Although some physicians prefer this method because of its technical ease and high success rate, this method has some important disadvantages. It requires the patient to be in a prone position, which may not be possible for the patient with multiple trauma. Monitoring the patient during procedural sedation is also difficult.

The prone patient is placed so the pelvis on the affected side hangs either over the end or over the side of the stretcher. The hip and knee are flexed to 90^o. Downward pressure is applied to the popliteal fossa, providing traction in-line with the deformity. An assistant stabilizes the pelvis and trunk preventing the patient from being pulled off the stretcher.

Whistler technique

The patient is placed supine with ipsilateral knee flexed to 120^o. The physician stands on the affected side and places an arm under the ipsilateral knee with his or her hand resting on the contralateral knee. The pelvis and ankle are stabilized by an assistant or the physician’s free hand. The physician raises his or her arm, which applies an anterior force to the knee and subsequently to the affected hip.

Anterior dislocations

A modified Allis technique may be used. The patient is placed supine. The physician stands at the foot of the stretcher. Traction is applied to a neutral hip while an assistant stabilizes the pelvis. Gentle lateral traction applied to the proximal femur facilitates the femoral head clearing the acetabular rim.

Posterior dislocations

See Joint Reduction, Hip Dislocation, Posterior.

Treatment

Prehospital Care

• Patients with hip dislocation often have associated injuries that may take precedence during stabilization, both in the field and in the ED. Attempts to reduce the dislocation in the field are ill advised.
• Establish the ABCs with appropriate spinal immobilization.
• If hip dislocation is detected in the field, the patient should be placed on a backboard and allowed to assume the leg position that is most comfortable (ie, hip slightly flexed, leg adducted).
• The patient should be transported to a level of trauma center appropriate for his or her overall clinical status.

Emergency Department Care

• Patients with hip dislocations often have life-threatening injuries that take precedence. Once life-threatening injuries have been stabilized or ruled out, the hip dislocation can be addressed. A proper neurovascular examination should be performed. If a neurovascular deficit exists, there is even more urgency to reduce the dislocation.   
• Appropriate analgesia should be provided. If hemodynamic status permits, intravenous narcotics are usually indicated.
• Radiographs to detect hip pathology should be obtained.
• Reduction is greatly facilitated by the use of procedural sedation. Unless sufficient sedation and muscle relaxation is achieved, attempts at relocation are futile. A variety of medications may be used for this purpose depending on physician preference and hospital protocol. A combination of agents with muscle relaxant and analgesic properties is optimal. The patient should be appropriately monitored during procedural sedation according to institutional protocol.
• Simple hip dislocations without associated fracture are within the practice scope of most emergency physicians. Consider orthopedic consultation if it will not delay relocation beyond a reasonable amount of time, usually within 6 hours.
• Once procedural sedation has been achieved, the hip may be reduced by one of the preceding methods. Reducing a hip usually takes a significant amount of space and resources. Usually, one person applies traction and one or two people supply counter traction. A nurse or other physician provides sedation. More than 3 attempts at closed reduction in the ED is not recommended. The incidence of AVN increases with multiple attempts. If the dislocation cannot be reduced, an emergent CT scan is indicated to visualize any bony or soft tissue fragments that may hinder reduction. Closed reduction may be attempted in the operating room under general anesthesia. However, a majority of these patients may require open reduction. 
• Fracture-dislocations or concomitant fractures of the femoral neck usually require the expertise of an orthopedic specialist. Practice styles vary widely. Some orthopedists make an attempt at closed reduction, whereas others immediately perform an open reduction if a fracture-dislocation exists. 
• After closed reduction, confirm placement with a repeat radiograph. A repeat neurovascular examination should be performed and documented as well. A CT scan or MRI of the hip can provide valuable information about further treatment and prognosis. 
• If relocation of the hip is successful, immobilize the legs in slight abduction by using a pad between the legs to prevent adduction until skeletal traction can be instituted.
• After reduction, patients with hip dislocation should be admitted to the hospital. Patients will be nonambulatory and require a great deal of supportive care. Pain will be significant, even after reduction, and patients may require parenteral narcotics. 
• The duration of traction and non–weight-bearing immobilization is controversial. Evidence suggests that early weight bearing (eg, 2 wk after relocation) may increase the severity of aseptic necrosis when it occurs. Early weight bearing decreases the incidence of other complications (eg, venous thromboembolism, decubiti), and some studies have found equivalent outcomes with early and delayed weight bearing.
• Indications for open reduction
  • Irreducible dislocation (approximately 10% of all dislocations)
  • Persistent instability of the joint following reduction (eg, fracture-dislocation of the posterior acetabulum)
  • Fracture of the femoral head or shaft
  • Neurovascular deficits that occur after closed reduction

Consultations

• Orthopedic surgeon
• Trauma surgeon

Medication

Administer adequate parenteral analgesia. The emergency physician, consultant, and patient must decide on the most appropriate type and place for reduction: open versus closed and emergency department versus operating room.

If a closed reduction is attempted in the ED, the patient requires procedural sedation. Procedural sedation policies should be established to define who can administer medication, who must monitor the patient, the classes and doses of procedural sedation medications, and the resources on hand for resuscitation.

In addition to airway protection and rescue, the procedural sedation goals must include pain relief, muscle relaxation, and procedure amnesia.

General anesthesia in the operating room may be required for patients with dislocations that are irreducible by closed means as well as for those with significant associated fractures, central dislocations, or associated neurovascular injury.

Analgesics

Pain control is essential to good-quality patient care. It ensures patient comfort, promotes pulmonary toilet, and aids physical therapy regimens. The analgesic must have a rapid onset, predictable action, and be easily titratable.

Morphine sulfate (Duramorph, MS Contin, MSIR)

DOC for analgesia because of reliable and predictable effects, safety profile, and ease of reversibility with naloxone.
Various IV doses are used; commonly titrated until desired effect obtained.

Dosing

Adult

Starting dose: 0.1 mg/kg IV/IM/SC
Maintenance dose: 5-20 mg/70 kg IV/IM/SC q4h
Relatively hypovolemic patients: Start with 2 mg IV/IM/SC; reassess hemodynamic effects of dose

Pediatric

Infants and children: 0.1-0.2 mg/kg IV/IM/SC q2-4h prn; not to exceed 15 mg/dose; may initiate at 0.05 mg/kg/dose

Interactions

Phenothiazines may antagonize analgesic effects of opiate agonists; tricyclic antidepressants, MAO inhibitors, and other CNS depressants may potentiate adverse effects of morphine

Contraindications

Documented hypersensitivity; hypotension; potentially compromised airway where establishing rapid airway control would be difficult

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in hypotension, respiratory depression, nausea, emesis, constipation, urinary retention, atrial flutter, and other supraventricular tachycardias; has vagolytic action and may increase ventricular response rate

Fentanyl citrate (Duragesic, Sublimaze)

More potent narcotic analgesic with shorter half-life than that of morphine sulfate. Suitable for procedural sedation analgesia. Excellent choice for pain management and sedation; has short duration (30-60 min) and easy to titrate. Easily and quickly reversed by naloxone.

Dosing

Adult

0.5-2 mcg/kg/dose IV/IM initially; titrate

Pediatric

<2 years: 2-3 mcg/kg/dose IV/IM q30-60min
2-12 years: 1-2 mcg/kg/dose q60min
>12 years: Administer as in adults

Interactions

Phenothiazines may antagonize analgesic effects; tricyclic antidepressants may potentiate adverse effects

Contraindications

Documented hypersensitivity; hypotension; potentially compromised airway in which establishing rapid airway control would be difficult

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in hypotension, respiratory depression, constipation, nausea, emesis, and urinary retention; idiosyncratic reaction, known as chest wall rigidity syndrome, may require neuromuscular blockade in order to increase ventilation

Meperidine (Demerol)

Narcotic analgesic with multiple actions similar to those of morphine. May produce less constipation, smooth muscle spasm, and depression of cough reflex than similar analgesic doses of morphine.

Dosing

Adult

50-150 mg PO/IV/IM/SC q3-4h prn

Pediatric

1-1.8 mg/kg (0.5-0.8 mg/lb) PO/IV/IM/SC q3-4h prn; not to exceed adult dose

Interactions

Monitor for increased respiratory and CNS depression with coadministration of cimetidine; hydantoins may decrease effects; avoid with protease inhibitors

Contraindications

Documented hypersensitivity; concurrent MAOIs; upper airway obstruction or significant respiratory depression; during labor when delivery of premature infant anticipated

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in head injuries (may increase respiratory depression and CSF pressure, use only if absolutely necessary); caution when using postoperatively and with history of pulmonary disease (suppresses cough reflex); substantially increased dose levels, because of tolerance, may aggravate or cause seizures even if no history of convulsive disorders; monitor closely for meperidine-induced seizure activity if prior seizure history; caution in elderly patients when repeated doses anticipated; caution when creatinine clearance <50 mL/min

Sedative hypnotics

Use these agents for procedural sedation with rapid onset and short duration.

Propofol (Diprivan)

Phenolic compound; sedative hypnotic agent used for induction and maintenance of anesthesia or sedation; has anticonvulsant properties.

Dosing

Adult

Induction dose for ASA class I/II: 1-2 mg/kg IV; if too fast, rapid sedation and apnea possible; if too slow, desired sedation and relaxation might not occur

Pediatric

General anesthesia induction:
<3 years: Not established
>3-16 years and ASA class I/II: 2.5-3.5 mg/kg IV over 20-30 sec; then 125-150 mcg/kg/min IV during initiation
Maintenance: 200-300 mcg/kg/min IV during first 30 min
Doses listed are for patients categorized as ASA I/II who have not received premedication or light premedication (eg, PO benzodiazepines, IM opioids)

Interactions

Reduce dose with concomitant benzodiazepines, opiates, phenothiazines, ethanol, and narcotics; may potentiate neuromuscular blockade of vecuronium; theophylline may weaken effects (may need to increase dose)

Contraindications

Documented hypersensitivity; those who are not mechanically ventilated

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Do not administer with blood or blood products using the same IV catheter; patients may develop apnea; may experience a decrease in systemic vascular resistance leading to hypotension

Anxiolytics

Patients with painful injuries usually experience significant anxiety. Anxiolytics allow the clinician to administer a decreased dose of an analgesic to achieve the same effect.

Diazepam (Valium)

By increasing activity of GABA, major inhibitory neurotransmitter, depresses all levels of CNS including limbic and reticular formation. Individualize dose and increase it cautiously to avoid adverse effects.

Dosing

Adult

5 mg PO/IV/IM q2-4h prn; not to exceed 30 mg/8 h

Pediatric

0.05-0.3 mg/kg/dose IV/IM over 2-3 min; repeat in 2-4 h prn; 0.12-0.8 mg/kg/d PO divided q6-8h; not to exceed 10 mg/dose

Interactions

Phenothiazines, barbiturates, alcohols, and MAO inhibitors increase CNS toxicity when administered concurrently

Contraindications

Documented hypersensitivity; narrow-angle glaucoma

Precautions

Pregnancy

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Caution with other CNS depressants, low albumin levels, or hepatic disease (may increase toxicity)

Lorazepam (Ativan)

Sedative hypnotic in benzodiazepine class that has short onset of effect and relatively long half-life. By increasing activity of GABA, major inhibitory neurotransmitter, may depress all levels of CNS, including limbic and reticular formation. Excellent medication when patient needs to be sedated for >24 h.

Dosing

Adult

1-10 mg/d IV divided bid/tid; not to exceed 4 mg/dose

Pediatric

0.05-0 .1 mg/kg IV slowly over 2-5 min; may repeat with 0.5 mg/kg IV slowly; not to exceed 4 mg/dose

Interactions

Toxicity of benzodiazepines in CNS increases when used concurrently with alcohol, phenothiazines, barbiturates, and MAO inhibitors

Contraindications

Documented hypersensitivity; preexisting CNS depression; hypotension; narrow-angle glaucoma

Precautions

Pregnancy

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Caution in renal or hepatic impairment, myasthenia gravis, organic brain syndrome, or Parkinson disease

Follow-up

Further Inpatient Care

• A variety of techniques can be used to accomplish open reduction, acetabular repair, and fixation of associated fractures; these techniques are beyond the scope of this article.
• After reduction of the hip dislocation, obtain repeat AP and lateral radiographs of the hip, as well as repeat CT scans or MRIs of the hip to verify proper reduction.
• After either open or closed reduction of a hip dislocation, the patient is instructed to remain on bed rest with his or her legs abducted and with skeletal traction designed to keep the hip from displacing posteriorly.
• The duration of traction is approximately 2 weeks, but the recommended period with no weight bearing is controversial and varies from 9 days to 3 months.

Further Outpatient Care

• An MRI 2-3 months after reduction can verify proper location and to screen for complications, such as avascular necrosis (AVN), osteoarthritis, and heterotopic calcification, at an early stage.
• Aggressive rehabilitation should be scheduled as soon as the patient can bear weight.
• Patients with AVN or severe osteoarthritis after a hip dislocation may require replacement of the hip with a prosthetic joint.

Inpatient & Outpatient Medications

• Appropriate analgesics and sedatives are required during hospitalization.
• Nonsteroidal anti-inflammatory medications (NSAIDs) may be required on an outpatient basis.

Transfer

• Once stabilized, patients with multiple trauma may be transferred.
• A patient with an isolated hip dislocation may be transferred if no neurovascular deficit is suspected and if the transfer time does not extend the dislocation time by longer than 6 hours.
• In general, hip dislocations are reduced at the receiving facility and, if necessary, the patient is transferred for ongoing inpatient care with appropriate immobilization en route.

Complications

• AVN of the hip
  • AVN is common, occurring in 8-13% of patients.
  • Early diagnosis and treatment of dislocations decreases the incidence of AVN.
  • The effect of early weight bearing on the occurrence of AVN is controversial. Most studies have shown that early weight bearing after reduction is associated with more severe AVN, but it does not appear to increase the incidence.
  • The incidence of AVN is increased with delayed reduction, repeated attempts at reduction, and open reduction (40% vs 15.5% with closed reduction). This finding may be due to operative trauma or because those dislocations requiring surgery are inherently more severe.
  • AVN may not become apparent on plain radiographs for several months. Early diagnosis can be made with MRI or nuclear scanning, and these modalities should be considered in a patient who develops late and persistent pain after a dislocation.
• Other complications of hip dislocation are the following:
  • Osteoarthritis
  • Heterotopic calcification
  • Recurrent dislocation
  • Ligamentous injury of the knee, other fractures
  • Complications of immobilization (DVT, pulmonary embolus, decubiti, pneumonia)
  • Sciatic nerve injury (posterior dislocation)
    • Injury to the sciatic nerve occurs in 10-14% of posterior dislocations during the initial trauma or during relocation.
    • Function of the sciatic nerve should be verified before and after relocation to detect this complication. The finding of sciatic nerve dysfunction mandates surgical exploration to release or repair the nerve.
  • Femoral-nerve injury
    • Anterior dislocations are occasionally associated with injury to the femoral artery or nerve.
    • Dislocations in children can occur with relatively minor trauma (eg, sports activities), and reduction must be gentle to avoid iatrogenic injury to the femoral epiphysis (eg, slipped capital femoral epiphysis).
    • Femoral-artery injury (in anterior dislocations)

Prognosis

• The prognosis of the patient with a hip dislocation varies with the type of dislocation, with the associated fractures of the femoral head or acetabulum, and the presence of other injuries. Overall, good-to-excellent results are obtained in 50-93% of patients.
• The principal determinants of a poor prognosis are as follows:
  • AVN occurs in 4-21.8% of patients in some reviews and 8-13% in others. The incidence is increased with delays in reduction beyond 6 hours and with open reduction. The severity of AVN increases in patients who undergo early weight bearing. AVN is a severe complication that usually requires replacement with a prosthetic hip.
  • Severe osteoarthritis occurs in at least 10% of patients and is more common in older patients. This seems to be an increased incidence compared to populations without hip dislocations of a similar age, and some authors have found the incidence to range from 30-71% after open reduction.
  • Injury to either the femoral or sciatic nerve usually consists of a neurapraxia, and eventual recovery of function can be expected in these cases. Permanent injury to these nerves can occur, resulting in disabling deficits. If patients have a neurological deficit, surgery is usually not indicated. Electromyography can help determine prognosis.
  • Recurrent dislocation is a complication if supporting ligaments have been disrupted.

Patient Education

• For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education article Total Hip Replacement.

Miscellaneous

Medicolegal Pitfalls

Clinical pitfalls in the management of hip dislocation include the following:

• Failure to diagnose hip dislocation in the presence of associated femoral-shaft fracture
• Reliance on a single AP pelvis radiograph may result in a missed posterior hip dislocation because the femoral head appears to be in the proper place
• Ascribing hemorrhagic shock to blood loss associated with a hip fracture (eg, missing associated intrathoracic or intra-abdominal injuries)
• Failure to test femoral and sciatic nerve function and distal perfusion before and after attempts at closed reduction
• Attempting to reduce a hip dislocation without proper sedation and analgesia
• More than 3 attempts at relocation in the emergency department

Special Concerns

• Patients with dislocation of a prosthetic hip
  • Hip prostheses frequently deteriorate over time and may dislocate with minimal trauma, such as crossing the legs or standing up.
  • The prosthesis is most susceptible to dislocation at 3-4 months after the initial surgery.
  • Reducing such dislocations is less urgent than reducing a native hip dislocation if the neurovascular status is intact. The concern regarding AVN and osteoarthritis is nonexistent.
  • Reduction is accomplished in identical fashion, and treatment is the same as that for nonprosthetic hips. Less force is used because these patients have poor bone structure and are prone to iatrogenic fracture. These patients can be mobilized to bear weight sooner than those with nonprosthetic hip dislocation.
• Neonates
  • Developmental dysplasia of the hip is a common problem that can result in dislocation or severe deformity of the hip joint.
  • Patients are routinely screened for this condition during the initial newborn examination by the Ortolani test (ie, eliciting a click on passive abduction of the flexed hip). Although this situation rarely arises in the ED, this test should be part of the normal newborn examination.
  • Patients with Down syndrome are more susceptible than others to hip dislocation.
• Children
  • If an increased acetabular angle is noted, that is, an increased slope in a line drawn from the upper outermost acetabulum to the center of the acetabulum, this is a sign of possible acetabular dysplasia or subluxation. This condition warrants further investigation.
  • Children may dislocate a hip more easily and with a lesser mechanism of injury than adults. Interpretation of radiographs is complicated by the presence of open epiphyses. Salter fractures may occur.
  • Reduction should be accomplished in a very gentle fashion, under general anesthesia or deep conscious sedation, to avoid producing iatrogenic fracture, slipped capital femoral epiphysis, or other epiphyseal injury.

Multimedia

Media file 1: Right posterior hip dislocation in a young woman following a high-speed motor vehicle collision (MVC).

Media file 2: Fracture-dislocation of the right hip. The bony fragments are likely part of the acetabulum.

Media file 3: Posterior dislocation of right hip with acetabular fracture.

Media file 4: A normal anteroposterior (AP) pelvis radiograph.

References

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Keywords

hip dislocation, dislocation hip, traumatic hip dislocation, prosthetic hip dislocation, hip dysplasia, congenital hip dislocation, CDH, developmental dysplasia of the hip, DDH, hip fracture-dislocation

Contributor Information and Disclosures

Author

Edward T Tham, MD, Fellow in Emergency Ultrasound, Clinical Instructor, Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine
Edward T Tham, MD is a member of the following medical societies: Alpha Omega Alpha
Disclosure: Nothing to disclose.

Coauthor(s)

Christopher I Doty, MD, FACEP, FAAEM, Assistant Professor of Emergency Medicine, Residency Program Director, Department of Emergency Medicine, Kings County Hospital Center, State University of New York Downstate Medical Center
Christopher I Doty, MD, FACEP, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, Council of Emergency Medicine Residency Directors, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

James E Keany, MD, FACEP, Medical Director, JetWest International Air Ambulance; Consulting Staff, Department of Emergency Services, Mission Hospital Regional Medical Center; Host of Healthbuzz at Jim.MD
James E Keany, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, American College of Sports Medicine, and California Medical Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Eric L Legome, MD, Chair, Department of Emergency Medicine, St Vincent's Hospital Manhattan; Associate Professor, Department of Emergency Medicine, New York Medical College
Eric L Legome, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Barry E Brenner, MD, PhD, FACEP, Professor of Emergency Medicine, Professor of Internal Medicine, Program Director, Emergency Medicine, University Hospitals, Case Medical Center
Barry E Brenner, MD, PhD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Chest Physicians, American College of Emergency Physicians, American College of Physicians, American Heart Association, American Thoracic Society, Arkansas Medical Society, New York Academy of Medicine, New York Academy of Sciences, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

The authors and editors of eMedicine gratefully acknowledge the contributions of previous authors, Jerome FX Naradzay, MD, Paul Carter, MD, and Edward Newton, MD, to the development and writing of this article.

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