eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Dislocation, Hip: Follow-up

Author: Edward T Tham, MD, Fellow in Emergency Ultrasound, Clinical Instructor, Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine
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
Contributor Information and Disclosures

Updated: Dec 2, 2008

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.

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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