eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Dislocation, Hip

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

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.   

More on Dislocation, Hip

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References

References

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  2. Conway WF, Totty WG, McEnery KW. CT and MR imaging of the hip. Radiology. Feb 1996;198(2):297-307. [Medline].

  3. DeLee JC. Fracture and dislocation of the hip. In: Rockwood CA, Green DP, Bucholz RW, et al, eds. Fractures in Adults. 4th ed. Lippincott Williams & Wilkins; 1996:1756-803.

  4. Frazee BW, Park RS, Lowery D, et al. Propofol for deep procedural sedation in the ED. Am J Emerg Med. Mar 2005;23(2):190-5. [Medline].

  5. McNamara R. Management of common dislocation: hip dislocations. In: Roberts J, Hedges J, eds. Clinical Procedures in Emergency Medicine. 4th ed. Philadelphia, PA: W. B. Saunders Co; 2004:Chap 50.

  6. Miner JR, Martel ML, Meyer M, et al. Procedural sedation of critically ill patients in the emergency department. Acad Emerg Med. Feb 2005;12(2):124-8. [Medline].

  7. Monma H, Sugita T. Is the mechanism of traumatic posterior dislocation of the hip a brake pedal injury rather than a dashboard injury?. Injury. Apr 2001;32(3):221-2. [Medline].

  8. Morrey BF. Instability after total hip arthroplasty. Orthop Clin North Am. Apr 1992;23(2):237-48. [Medline].

  9. Pitetti RD, Singh S, Pierce MC. Safe and efficacious use of procedural sedation and analgesia by nonanesthesiologists in a pediatric emergency department. Arch Pediatr Adolesc Med. Nov 2003;157(11):1090-6. [Medline].

  10. Walden PD, Hamer JR. Whistler technique used to reduce traumatic dislocation of the hip in the emergency department setting. J Emerg Med. May-Jun 1999;17(3):441-4. [Medline].

  11. Introduction: congenital hip dislocation. WrongDiagnosis Web site. Available at http://www.wrongdiagnosis.com/c/congenital_hip_dislocation/intro.htm. Accessed May 29, 2003.

  12. Yang EC, Cornwall R. Initial treatment of traumatic hip dislocations in the adult. Clin Orthop Relat Res. Aug 2000;24-31. [Medline].

  13. Goulet J. Hip dislocation. In: Browner B, ed. Skeletal Trauma: Basic Science, Management and Reconstruction. 3rd ed. Philadelphia, PA: Elsevier Science; 2003:chap 46.

  14. Newton E. Femur and hip. In: Marx J, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, PA: Mosby Elsevier; 2006:chap 53.

  15. Sahin V, Karakas ES, Aksu S, et al. Traumatic dislocation and fracture-dislocation of the hip: a long-term follow-up study. J Trauma. Mar 2003;54(3):520-9. [Medline].

  16. Hillyard RF, Fox J. Sciatic nerve injuries associated with traumatic posterior hip dislocations. Am J Emerg Med. Nov 2003;21(7):545-8. [Medline].

  17. Goddard NJ. Classification of traumatic hip dislocation. Clin Orthop Relat Res. Aug 2000;11-4. [Medline].

  18. Nordt WE 3rd. Maneuvers for reducing dislocated hips. A new technique and a literature review. Clin Orthop Relat Res. Mar 1999;260-4. [Medline].

Further Reading

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.

 
 
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