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Clinical Procedures > Musculoskeletal Procedures
Joint Reduction, Hip Dislocation, Posterior
Article Last Updated: Nov 7, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 12  
Author: James Emanuel Rodriguez, MD, Staff Physician, Department of Emergency Medicine, New York University/Bellevue Hospital
James Emanuel Rodriguez is a member of the following medical societies: American College of Emergency Physicians, American College of Sports Medicine, and Emergency Medicine Residents Association
Coauthor(s):
Moira Davenport, MD, Consulting Staff, Departments of Emergency Medicine and Orthopedic Surgery, Allegheny General Hospital
Editors: Erik D Schraga, MD, Consulting Staff, Permanente Medical Group, Kaiser Permanente, Santa Clara Medical Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Luis M Lovato, MD, Assistant Clinical Professor, David Geffen School of Medicine at UCLA; Director of Critical Care, Department of Emergency Medicine, Olive View/UCLA Medical Center; Gil Z Shlamovitz, MD, Assistant Professor of Emergency Medicine, University of Connecticut School of Medicine; Attending Physician, Emergency Department, Windham Memorial Community Hospital, Willimantic, CT; Attending Physician, Emergency Department, Hartford Hospital, Hartford, CT; Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital
Author and Editor Disclosure
Synonyms and related keywords:
hip dislocation, hip relocation, posterior hip dislocation, simple hip dislocation, complex hip dislocation, joint reduction, hip reduction, hip joint reduction, sciatic nerve, nerve compression, dashboard injuries, osteoarthritis, osteonecrosis, equinus deformity, avascular necrosis
Hip dislocations, regardless of their etiology, are orthopedic emergencies that require immediate diagnosis, evaluation, and treatment.1 The adult hip joint is remarkably stable. It is reinforced with thick capsular and labral structures. The presence of a dislocation injury indicates a large force from a traumatic mechanism (a traction force of at least 90 lb) or the presence of underlying pathology leading to inherent instability of the joint. Posterior dislocations make up 80-95% of traumatic hip dislocations.
Such a large force injury suggests the need for Advanced Trauma Life Support (ATLS) to be initiated in the initial assessment of the patient. Pediatric hip dislocations may occur with smaller amounts of force and have been documented after gymnastic maneuvers and falls from standing. Elderly patients or those with Ehlers-Danlos Syndrome or Down Syndrome are also more likely to dislocate a hip with smaller amounts of traumatic force.
Posterior traumatic hip dislocations occur when the force acts with adduction, internal rotation, and some degree of flexion of the hip. The incidence of this injury has increased in recent decades because of high-velocity motor vehicle use.1 Injuries in which the front seat passengers are involved in a head-on collision that drives the dashboard into their lower extremities (known as dashboard injuries) have become a notorious cause of posterior traumatic hip displacement. Of note, this mechanism of injury is associated with an incidence of simultaneous severe knee injury in 26% of patients, including patellar fractures in 4% of patients. The difficulty in detecting a knee injury in a patient who has a dislocated hip underscores the need for the physician to maintain a high index of suspicion for multiple lower extremity injuries (eg, acetabular and femoral head, neck, or shaft fractures) as well as occult visceral damage.
Typically, the patient with a posterior traumatic hip dislocation presents with a notably shortened lower limb held in a position of hip flexion, adduction, and internal rotation.2 The presence of the femoral head may sometimes be palpable at the ipsilateral buttock. While this presentation is reliable in patients with simple hip dislocations, the presence of fractures in the ipsilateral femur or pelvis may dramatically alter the patient's presenting position. A high incidence of undetected hip dislocations in patients with ipsilateral fractures, as well as the marked increase in long-term morbidity when initial reduction is delayed, illustrates the need to be able to recognize atypical presentations of this injury.
Plain film radiographs are usually the diagnostic modality of choice, as these can be performed and evaluated in a very short amount of time. Because of the observance of ATLS protocols, an anteroposterior (AP) view of the pelvis, including adequate views of the bilateral hips, is commonly the only film acquired before the diagnosis is confirmed. An additional lateral or Judet oblique view of the pelvis may add more information about the presence and direction of the dislocation and may be obtained provided that it does not interfere with the acute resuscitation of the patient.
Posterior hip dislocations can be visualized well on an AP film2 by the presence of the femoral head outside and just superior to the acetabulum. They may commonly be associated with ipsilateral acetabular (81% of posterior hip dislocations in adults have posterior acetabular fractures) or femoral fractures. If the plain films are questionable or if the patient is stable without additional injury, a CT scan of the hip can be used to diagnose and describe the anatomy of the dislocation and identify small fracture fragments. Use of CT should only be pursued if it can be both performed and evaluated in an extremely timely manner, since the reduction attempt must not be delayed.
Multiple studies have demonstrated that the ultimate morbidity for the patient increases as the time interval from injury to reduction increases.2, 3 Complications such as osteonecrosis of the femoral head, arthritic degeneration of the hip joint, and long-term neurological sequelae become more likely as reduction is delayed. While the goal is to perform an adequate reduction as quickly as possible, careful prereduction evaluation must be performed to properly diagnose the injury. Optimally, the reduction should be performed within 6 hours from the time of injury. If adequate closed reduction cannot be attained or if a nerve palsy becomes apparent after closed reduction is achieved, emergent operative reduction is required.
- Emergent closed reduction for traumatic hip dislocation
- Closed reduction is indicated for a dislocation with or without neurologic deficit when no associated fracture is present.
- Closed reduction is indicated for a dislocation with an associated fracture if neurological deficits are not present.
- Closed reduction attempt before open surgical reduction for traumatic hip dislocation
- Open surgical reduction is usually required for a hip dislocation with an associated fracture and neurological deficits (the displaced fracture fragment is most likely compressing the nerve).
- If open reduction cannot be performed emergently, an attempt to decompress the nerve with closed reduction is indicated and should be performed.
- Open traumatic hip dislocation (suggests extremely large forces)
- Such injuries are associated with high infection rates and up to 50% mortality from the injury.
- Patients with such injuries are generally brought directly to the operating room for treatment with surgical irrigation, debridement, and open reduction.
- If operative management is delayed, closed reduction may be attempted, with follow up operative management as soon as possible.
- Multiple failed closed reduction attempts
- If the hip cannot be relocated after multiple (2-3) reduction attempts, then emergent operative exploration is indicated.
- Further closed reduction attempts should not be initiated at this point.
- Procedural sedation is usually indicated.
- A dedicated physician should be responsible only for the procedural sedation.
- For more information, see Procedural Sedation.
- General anesthesia in the operating room is an alternative.
- Oxygen supply
- Bag valve mask
- Oxygen saturation monitor
- Wall suction, suction tubing, and Yankauer suction catheter
- Intravenous catheter (≥20 gauge)
- Medications as needed for procedural sedation
- Normal saline (0.9% NaCl) flushes
- Various techniques have been proposed to accomplish closed reduction of posterior hip dislocations, including maneuvers performed with the patient in supine or prone positions and maneuvers performed by one or several practitioners.
- The following is an illustration of a well-established reduction method (the Bigelow maneuver) that may be performed with minimal assistance with the patient in the supine position.
- Place the patient supine on a stretcher that is elevated to the height of the waist of the physicians performing the reduction.
- The injured hip is initially held in a position of adduction and internal rotation, with one physician applying longitudinal distraction and an assistant applying pressure on the patient's anterior superior iliac spines so as to stabilize the patient's pelvis.
The initial position for closed reduction of a posteriorly dislocated hip.
- Obtain and document a thorough preprocedure history that includes the following:
- History of prior injuries and surgeries
- The mechanism of trauma
- Amount of time that has elapsed since the traumatic event
- A description of the presenting symptoms
- Any subjective loss of strength or sensation
- The patient’s age in reference to skeletal maturity
- Perform and document a thorough physical examination.
- Special attention should be paid to noting ecchymoses; swelling; pallor; abrasions; lacerations; paraesthesia; weakness; notable deformities of the hip; and the presence and character of femoral, popliteal, and pedal pulses.
- The exact position in which the hip and distal leg are held should be noted, as well as a comparison examination of the contralateral hip, keeping in mind that bilateral hip dislocations are a rare but well-described occurrence.
- Emphasis should be placed on assessing the neurovascular status of the distal limb, particularly in assessing the sciatic distribution.
- Assess the patient for additional injuries, particularly life-threatening injuries that may have resulted from the same high-force trauma that caused the hip dislocation. Follow ATLS protocols when deemed appropriate. Continue management of the hip dislocation as soon as proper evaluation and resuscitation of the patient have insured hemodynamic stability.
- Obtain radiographs of the patient's bilateral hips and pelvis, choosing the type of radiograph that can be performed and evaluated in the shortest duration of time and make the diagnosis. Choices include the following:
- A single AP pelvis view that shows both hips (If the patient is unstable and is being treated with ATLS protocols, this view may be the only option.)
- An AP pelvis and a lateral or oblique Judet view (This may provide more information then a single AP pelvis view; additional radiographs may be difficult to obtain secondary to the patient's pain, and the acquisition of the additional views should not delay patient care.)
- A CT scan of the hip that includes the area from the iliac crest to the symphysis pubis (While this diagnostic modality provides excellent visualization of the injury, this study should only be sought if it can be quickly obtained and evaluated.)
- Obtain informed consent.
- Prepare for and perform procedural sedation as described in the Anesthesia section.
- Have an assistant stabilize the pelvis by grasping the bilateral anterior superior iliac spines and applying gentle posterior force.
- Apply longitudinal distraction of the injury by grasping the patient’s distal femur, bringing the femoral head from behind the acetabular rim.
- The leg should be held in a position of relative adduction and internal rotation.
- Several moments of persistent traction may be needed to relax the large musculature of the hip; this joint laxity helps to facilitate the subsequent maneuvers.
- Once the leg has been brought out to length, bring the hip to 90° of flexion while allowing the ipsilateral knee to flex passively.
- Gently abduct, externally rotate, and extend the hip while distracting the femoral head anteriorly. Large amounts of rotational force should be avoided, since this has been associated with iatrogenic femoral neck fractures.
- When the femoral head returns to the acetabulum, an audible or palpable "clunk" can be appreciated.
- While the procedural sedation is still in effect, gently take the reduced hip through a full passive range of motion (ROM), being mindful of any additional fractures or injuries the patient may have sustained.
- The stable reduced hip should remain in anatomic position through these maneuvers.
- Repeat hip dislocation during this passive ROM exercise is diagnostic of clinical joint instability. Longitudinal skeletal traction is required to stabilize such an injury.
- Place the affected extremity in a pillow brace to ensure stability during transport.
- Once reduction has been achieved, repeat radiography is required to ensure concentric anatomic placement of the femoral head. While plain film radiography is usually enough to adequately visualize the reduction, a CT scan is superior in that it may also show small intraarticular fragments and marginal impaction, as well as residual subluxation of as little as 2 mm within the joint.2
- Long-term orthopedic follow-up should be arranged in conjunction with the orthopedic specialist, who will continue to treat this patient. Many patients require inpatient management for this or other injuries. If outpatient management is deemed appropriate, the patient should have a follow-up appointment within a few days of the injury.
- Outpatient instructions should include the following:
- The patient should not bear weight on the injured hip for several weeks or until the patient’s first follow-up appointment.
- The hip should be splinted and maintained in a safe position that does not allow for any tension on the healing capsular structures.
- The patient should return for emergent care immediately if he or she experiences an increase in pain, an onset of groin pain, or any numbness or weakness in the ipsilateral leg.
- The patient should follow instructions for pain medicine, as deemed appropriate. Narcotics, nonsteroidal antiinflammatory drugs (NSAIDs), or both are usually warranted.
- Patients who present after successful reduction with groin pain (particularly groin pain that radiates to the ipsilateral thigh) are likely describing the pain of osteonecrosis of the femoral head.
- Hip radiographs are indicated.
- Radiographic signs of osteonecrosis within the femoral head are used to stratify patients into a classification system that has prognostic value and aids in future therapeutic decision-making for the treatment of osteonecrosis.
- The staging system for osteonecrosis is as follows:4
- Stage 1 – Normal appearance of the femoral head; patient is symptomatic (A technetium-99 bone scan may be used to confirm the diagnosis.)
- Stage 2 – Femoral cysts, sclerotic changes, or both
- Stage 3 – Crescent sign of subchondral collapse of the femoral head
- Stage 4 – Joint space narrowing with acetabular cysts, osteophytes, and cartilage damage
- The size of the osteonecrotic portion of the femoral head and the stage of progression at the time of treatment initiation determine whether or not the ultimate outcome will be the loss of structural integrity and severe osteoarthritic degeneration of the hip.
- If adequate closed reduction cannot be accomplished, the dislocated hip should be held in a position of relative extension with the ipsilateral knee in flexion until open reduction is initiated. This is the position that puts the least amount of strain on the sciatic nerve.
- A sciatic stretch test may be used to predict whether future symptoms of damage to the sciatic nerve may occur. This is performed after a successful reduction in patients with no symptoms of neurological dysfunction. The test is performed as follows:
- Place the patient supine on a stretcher.
- Have the patient actively flex the relocated hip to a comfortable 90° of flexion.
- Passively extend the knee on the same side as the hip relocation with gentle force. Do not attempt to extend the knee past the patient's comfortable range limit.
- If the passive knee extension produces pain in the sciatic distribution of the same leg, damage to the sciatic nerve may have occurred; symptoms of this injury are more likely to reveal themselves in the future. The patient should be informed of this likelihood and be counseled that paresthesia or neurapraxia may occur in the future weeks or months.
- If neurological symptoms persist from the time of the injury despite adequate reduction, surgical nerve exploration may be performed several weeks after the injury. Emergency nerve exploration is usually not indicated if successful concentric closed reduction can be achieved and maintained in a simple traumatic dislocation. However, if no neurological deficit is apparent at the time of the injury, and such symptoms do appear several days to weeks later, they may be signs of nerve dysfunction attributable to heterotopic ossification or scar tissue formation and may indicate the need for surgical neurolysis as soon as possible. The patient without initial neurological deficits should, therefore, be made aware of this possibility and be instructed to seek treatment immediately if such symptoms occur.
- Osteonecrosis of the femoral head may be caused by traumatic hip dislocation.
- This complication occurs secondary to acute interruption of the femoral head's vascular supply from the ligamentum teres and retinaculum.
- The incidence of osteonecrosis is between 6% and 27% in timely reductions and up to 48% in delayed reductions.
- This complication occurs more often in traumatic hip dislocations that include posterior dislocation rather than anterior dislocation, associated femoral head fracture, or associated acetabular fracture.
- The incidence of osteonecrosis is the reason that traumatic hip dislocations represent a temporal emergency, and reductions performed at longer time intervals from the moment of the injury have been shown by repeated studies to be associated with higher incidences of osteonecrosis. While it is widely held that hip reduction should be performed within 6 hours of the injury to reverse the potential impingement of the femoral and posteromedial circumflex vessels, several studies have demonstrated excellent outcomes with reductions performed at even shorter intervals. These results suggest that decreasing the time to reduction as much as possible is most prudent to achieve the best probability of either decreasing the severity of osteonecrosis or avoiding it entirely.
- Neurological injury is one of the most common complications of hip dislocations, even when successful closed reduction is accomplished.5
- Sciatic neurapraxia, often from damage to the peroneal branch, occurs in up to 5% of pediatric dislocations and in approximately 10-15% of adult traumatic hip dislocations, though these symptoms partially or entirely resolve in 60-70% of cases.5
- The sciatic nerve can be lacerated, stretched, compressed, or encased in heterotopic ossification.5 Neurological symptoms may become apparent after a patient initially presents with a normal neurological examination.
- The symptoms may begin after proper closed reduction has been achieved, and the reduction technique itself may cause notable traction forces to be applied to the sciatic nerve, which may result in further injury.
- If sciatic dysfunction is apparent, prevention of equinus deformity must be addressed by ensuring adequate ankle dorsiflexion.5 The application of ankle dorsiflexion splints is needed if the patient is unable to actively dorsiflex the ipsilateral ankle.
- Postdislocation osteoarthrosis is a complication among adults with traumatic hip dislocations.
- This complication occurs in up to 24% of adults with traumatic hip dislocations without fractures and in 88% of those with hip dislocations that occurred with concomitant hip or acetabular fracture, particularly in those with acetabular fragments with more than 3 mm of displacement.
- While degenerative changes among children have been demonstrated, osteoarthritis after traumatic hip dislocation in the pediatric population has not been described.
- Interposition of the muscle or labrum causes up to 4% of adult simple posterior traumatic dislocations to be impossible to reduce.
- Hip dislocations associated with any type of fracture may have a larger subset of irreducible injuries due to interposition of osseous fragments and connective tissue components.
- These patients should be brought to the operating room as soon as possible for open reduction, and repeated (2-3) attempts at closed reduction should not be performed, as studies have associated repeat attempts with poor long-term results.
| Media file 1:
The initial position for closed reduction of a posteriorly dislocated hip. |
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- Morrey BF. Results of reoperation for hip dislocation: the big picture. Clin Orthop Relat Res. Dec 2004;(429):94-101. [Medline].
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Joint Reduction, Hip Dislocation, Posterior excerpt Article Last Updated: Nov 7, 2007
Topic originally published: Nov 7, 2007
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