Hip Dislocation

Hip Anatomy (http://www.health.act.gov.au/)

Definition: Separation of the femoral head from the acetabulum of the pelvis in either a posterior or anterior direction.

Classification and Mechanism

• Anatomic
  • Anterior Dislocation (10%)
    • Occurs with axial loading of hip in extension and abduction or from a significant posterior force on the joint forcing the femoral head anteriorly.
    • Can be shifted inferiorly (extension > flexion) or superiorly (flexion > extension)
  • Posterior Dislocation (90%)
    • Occurs with axial loading of hip in flexion and adduction. dashboard injury where the patient’s knee hits the dashboard/steering wheel in flexion and forces the femoral head posteriorly.
• Complexity: Stewart-Milford System (Egol, 2010)

Mechanistic Considerations

• As the femoral head dislocates, it can injure the femoral neurovascular bundle
• Diminishes blood supply to the femoral head leading to avascular necrosis
• Avascular necrosis can develop within 6 hours stressing the need for prompt identification and reduction (Hougaard 1986)
  • Reduction < 6 hours: 4.8% avascular necrosis
  • Reduction > 6 hours: 52.9% avascular necrosis

Epidemiology

• Uncommon injury, typically secondary to trauma or in non-native joints
  • Traumatic
    • 70% of all hip dislocations are dunne to motor vehicle collisions
    • Relatively rare in younger individuals, with only 5% occurring in individuals less than 14 years old (typically sports or fall- related). (Goodwin, 2011)
  • Post-Hip Arthroplasty
    • Dislocation one of the most common complications after arthroplasty, occurring due to laxity, implant positioning, improper implant choice and impingement. (Kendoff, 2013)
    • Frequency: (Eysel 2014) (Weatherford, 2011)
      • 2% after primary total hip arthroplasty
      • 28% after revision and implant exchange surgeries
      • 70% of dislocations occur within the first month and 75-90% posterior
• Associated with other injuries in up to 95% of traumatic cases (Goulet, 1999)
  • Acetabular fractures (70%)
  • Other extremity fractures (39%)
  • Closed head injuries (24%)
  • Craniofacial injuries (21%)
  • Thoracic injuries (21%)
  • Femoral head fractures (14%)

Physical Exam

• General
  • Severe pain
  • Inablity to move the affected lower extremity
• Hip Exam
  • Anterior Dislocation: mildly flexed, abducted and externally rotated
  • Posterior Dislocation: flexed, adducted and internally rotated
• Special Considerations
  • Complete a full trauma survey given frequency of associated injuries
  • Direct particular attention to ipsilateral joints given the large force transmitted through the lower extremity to cause the dislocation
    • Ipsilateral knee, patellar and femur fractures are common co-injuries
    • Meniscal and PCL injuries are common with dashboard type injuries
  • Complete a full neurovascular exam
    • Sciatic nerve injuries occur in up to 10% of cases.
    • Check dorsiflexion of the ankle and large toe (will be weak in anterior and posterior dislocations)

Imaging Modalities

• Initial imaging should include a plain hip with AP pelvis
  • If suspicion for associated fracture, subsequent CT is recommended to fully characterize the injury .
  • If a fracture is present, your orthopedics colleagues may prefer to manage the injury operatively and any closed manipulation may cause injury to surrounding neurovascular structures.
• Posterior Dislocation

Posterior Hip Dislocation (Case courtesy of Dr Hani Salam, Radiopaedia.org. From the case rID: 10397)

• Anterior Dislocation

Anterior Hip Dislocation (Case courtesy of Dr Sajoscha Sorrentino, Radiopaedia.org. From the case rID: 14836)

• Concomitant Fracture
  • Common in traumatic dislocations but may be difficult to visualize with X-rays
  • CT scan superior imaging modality if concern for fracture
    • Fracture of the anterior articular surface of the femoral head (black arrow)
    • Fracture of the posterior margin of the acetabulum (green arrow)
    • Fragment of bone (grey arrow) in the soft tissues posterior to the acetabulum, which had arisen from the posterosuperior femoral head

Fracture of Femoral Head with Dislocation (http://www.radpod.org)

Management

• Closed Reduction
  • Urgent reduction (<6 hours) should be performed in most cases to reduce the risk of osteonecrosis
  • If there is an associated hip/femoral neck fracture, the patient may require closed reduction under anesthesia or an open reduction in the OR
• 

  Allis Maneuver (Waddell 2016)

  Closed Reduction Techniques (Meyer, 2016)

  • Allis Maneuver
    • Place the patient supine in the bed with the physician either on the bed (as shown) or standing beside the patient
    • While an assistant stabilizes the pelvis, hold the ipsilateral leg just below the knee, flex it to 90 degrees and apply traction in line with the femur
    • As the hip begins to reduce, extend the hip and externally rotate to allow the femoral head to slide back into the acetabulum
• 

  Bigelow Maneuver (Waddell 2016)

  Bigelow Maneuver

  • Place the patient in the supine position with the physician standing beside the bed
  • Place your forearm beneath the patients knee and grasp the ankle with your opposite hand (as shown)
  • While an assistant stabilizes the pelvis, flex the hip to 90 degrees and apply traction in line with the femur while abducting, externally rotating and extending the hip until reduced
• 

  Rochester Maneuver (Waddell 2016)

  Rochester/Whistler Maneuver

  • Place the patient in the supine position with both legs flexed and the physician at the standing beside the bed
  • Slide your arm beneath the knee of the affected side and then hold the knee of the contralateral side
  • Place your hand on the ankle of the affected leg and apply downward traction at the ankle, internally and externally rotating as needed
• 

  Stimson Gravity Maneuver (Waddell 2016)

  Stimson Gravity Maneuver

  • Place the patient in a prone position with the legs over the side of the bed in 90 degrees flexion
  • Place one hand on the patient’s ipsilateral calf, just below the knee, and the under beneath the ipsilateral ankle (as shown)
  • Apply downward force on the lower extremity using the hand on the calf and use the hand on the ankle to apply internal/external rotation until the hip is reduced
• Captain Morgan
  • Place the patient in a supine position with the pelvis stabilized by and assistant or strapped to the bed
  • Stand on the side of the patients bed and place your knee, flexed at 90 degrees, beneath the patients ipsilateral leg, just distal to their knee (as shown)
  • Place your forearm beneath the patients knee and grasp the ankle with your opposite hand (as shown)
  • Apply upward traction with the hand behind the patient’s knee and internally/externally rotate at the ankle until the hip is reduced

• Open Reduction
  • Reduction in the OR
  • Consider in cases of irreducible dislocation, evidence of incarcerated fragments, unstable fracture-dislocation, delayed presentation (>6-12 hrs) or if the reduction is not concentric. (Bhandari, 2012)
• Post-Reduction Management
  • Imaging
    • A post-reduction X-ray should be obtained in all cases (native or non-native) and  a CT is recommended in traumatic cases of dislocation to rule out fracture.
  • Post-Discharge Care
    • Exercise Precautions (non-fractured):
      • Controlled passive range-of-hip motion exercises and early mobilization
      • Extremes of motion should be avoided for 4-6 weeks to allow for capsular and soft-tissue healing
      • Anterior: avoid hyperextension of the hip with external rotation
      • Posterior: avoid flexion of the hips past 45 degrees
    • Weight-bearing
      • Institution specific
      • No associated fracture: Generally full weight-bearing as tolerated
      • Associated fracture: depends on surgical vs. non-surgical management by orthopedics
    • Immobilization
      • Anterior: an abduction pillow may be helpful
      • Posterior: use a simple knee immobilizer
• Complications:
  • Osteonecrosis resulting from avascular necrosis
  • Chronic Pain/Arthritis
    • Post-traumatic arthritis can occur in up to 37.5% of patients with traumatic hip dislocation. (Srikrishnamurthy, 1983)

Take Home Points

• Early identification and reduction is key to prevent complications
• Always perform a full trauma and neuro exam, particularly of ipsilateral joints as concomitant injuries are common with traumatic dislocations
• Don’t be reassured by negative post-reduction XRs as small fractures can occur. You should always consider CT

Read More

ALiEM: PV Card: Hip Injuries

Orthobullets: Hip Dislocation

EMin5.com: Hip Dislocations

Radiopedia: Hip Dislocation

Sanders S et al. Traumatic hip dislocation–a review. Bull NYU Hosp Jt Dis. 2010;68(2):91-6. PMID: 20632983

Kovacevix D et al. Injuries about the hip in the adolescent athlete. Sports Med Arthrosc. 2011 Mar. 19 (1): 64-74. PMID: 21293240

Zahar A et al. Dislocation after total hip arthroplasty. Current Reviews in Musculoskeletal Medicine. 2013;6(4):350-356. PMID: 24170479

Dargel J et al. Dislocation Following Total Hip Replacement. Deutsches Ärzteblatt International. 2014;111(51-52):884-890. PMID: 25597367

Weatherford, B (2011, November). Hip Dislocation. Retrieved from http://www.orthobullets.com/recon/5012/tha-dislocation

Hak DJ1, Goulet JA. Severity of injuries associated with traumatic hip dislocation as a result of motor vehicle collisions. J Trauma. 1999 Jul;47(1):60-3. PMID: 10421188

Hougaard K, Thomsen PB. Traumatic posterior dislocation of the hip – prognostic factors influencing the incidence of avascular necrosis of the femoral head. Arch Orthop Trauma Surg. 1986;106:32-35. PMID: 3566493

Upadhyay SS et al. An analysis of the late effects of traumatic posterior dislocation of the hip without fractures. J Bone Joint Surg Br. 1983 Mar;65(2):150-2. PMID: 6826619

Waddell BS et al. A Detailed Review of Hip Reduction Maneuvers: A Focus on Physician Safety and Introduction of the Waddell Technique. Orthopedic Reviews. 2016;8(1):6253.  PMID: 27114811

Bhandari, M. Evidence-based Orthopedics. Chichester: Wiley Blackwell, 2012. Web.