Emergency Department Care
When hip dislocation occurs, patients 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 should be obtained to detect hip pathology.
Reduction is greatly facilitated by the use of procedural sedation. Unless sufficient sedation and muscle relaxation are 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 dislocation without associated fracture is within the practice scope of most emergency physicians. Consider orthopedic consultation if this will not delay relocation beyond a reasonable length 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 requires significant space and resources. Usually, 1 person applies traction and 1 or 2 people supply countertraction. A nurse or another physician can provide sedation. More than 3 attempts at closed reduction in the ED is not recommended. The incidence of AVN is increased 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 with the patient under general anesthesia. However, a majority of these patients will require open reduction.
Fracture-dislocation or concomitant fracture of the femoral neck usually requires 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, placement should be confirmed with a repeat radiograph. A repeat neurovascular examination should be performed and documented as well. 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 will 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 of non–weight-bearing immobilization is controversial. Evidence suggests that early weight bearing (eg, 2 weeks after relocation) may increase the severity of aseptic necrosis when it occurs. However, 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.
Once stabilized, a patient with multiple trauma may be transferred. A patient with an isolated hip dislocation may be transferred if no neurovascular deficit is suspected, and if transfer time does not extend 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.
Indications for open reduction
Indications for open reduction include the following:
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Irreducible dislocation (approximately 10% of all dislocations).
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Persistent instability of the joint following reduction (eg, fracture-dislocation of the posterior acetabulum).
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Fracture of the femoral head or shaft.
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Neurovascular deficits that occur after closed reduction.
An orthopedic surgeon and/or a trauma surgeon should be consulted.
Follow-up
Various techniques can be used to accomplish open reduction, acetabular repair, and fixation of associated fractures.
After the hip dislocation is reduced, obtain repeat AP and lateral radiographs of the hip to verify proper reduction.
After open or closed reduction of a hip dislocation, the patient is instructed to remain on bed rest with 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.
Complications
AVN of the hip
Avascular necrosis (AVN) is common, occurring in 8-13% of patients.
Early diagnosis and treatment of dislocation 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 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 to the fact that 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; these modalities should be considered for a patient who develops late and persistent pain after a dislocation.
Sciatic nerve injury (posterior dislocation)
Injury to the sciatic nerve during the initial trauma or during relocation occurs in 10-14% of patients with posterior dislocation.
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 dislocation is occasionally associated with injury to the femoral artery or nerve.
Dislocation in children can occur with relatively minor trauma (eg, sports activities); reduction must be gentle to avoid iatrogenic injury to the femoral epiphysis (eg, slipped capital femoral epiphysis).
Other complications
Other complications of hip dislocation include the following:
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Heterotopic calcification.
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Recurrent dislocation.
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Ligamentous injury of the knee, other fractures.
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Complications of immobilization (DVT, pulmonary embolus, decubiti, pneumonia).
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Femoral artery injury (in anterior dislocation).
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A normal anteroposterior (AP) pelvis radiograph.
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Right posterior hip dislocation in a young woman following a high-speed motor vehicle collision (MVC).
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Fracture-dislocation of the right hip. The bony fragments are likely part of the acetabulum.
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Posterior dislocation of right hip with acetabular fracture.
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Portable AP pelvis with subtle presentation of right posterior hip dislocation. Abnormal rotation is present, and the right femoral head appears smaller, indicating that it is further away.
