Adult Hip Dislocations: Causes, Symptoms, Emergency Treatment

A hip dislocation is a serious orthopedic emergency in which the femoral head is displaced from the acetabulum (hip socket). Due to the inherent stability of the hip joint, dislocations typically occur only after high-energy trauma such as motor vehicle accidents or falls from height.

Up to 50% of patients with hip dislocations sustain associated injuries, including fractures of the pelvis, femur, or spine.

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Epidemiology and Key Facts

• Most cases occur in men aged 16–40 years
• Motor vehicle accidents are the leading cause
• Posterior dislocations account for 85–90% of cases
• Anterior dislocations represent 10–15%
• Sciatic nerve injury: 10–20% (posterior cases)
• Osteonecrosis risk: 2–17%
• Post-traumatic arthritis: ~16%

Unrestrained passengers are at significantly higher risk, emphasizing the protective role of seatbelts.

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Anatomy of the Hip Joint

The hip is a ball-and-socket joint composed of:

• Femoral head (ball)
• Acetabulum (socket) formed by:
  • Ilium
  • Ischium
  • Pubis

Key Stabilizing Structures:

• Labrum → deepens the socket
• Capsule and ligaments:
  • Iliofemoral ligament
  • Pubofemoral ligament
  • Ischiofemoral ligament

Blood Supply:

• Primarily from:
  • Medial femoral circumflex artery
  • Lateral femoral circumflex artery
• Minor contribution:
  • Artery of ligamentum teres

Damage to this vascular network can lead to osteonecrosis (avascular necrosis).

See Also: Hip Joint Anatomy

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Mechanism of Injury

Hip dislocations usually result from high-energy trauma, including:

• Dashboard injuries (knee striking dashboard)
• Falls from height
• Industrial accidents

Force Transmission Sources:

1. Flexed knee impact
2. Axial load through the foot
3. Direct force on the greater trochanter

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Types of Hip Dislocations

1. Posterior Hip Dislocation (Most Common)

• Mechanism: Force on flexed knee (dashboard injury)
• Limb position:
  • Flexion
  • Adduction
  • Internal rotation

Associated Injuries:

• Posterior acetabular fractures
• Sciatic nerve injury

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2. Anterior Hip Dislocation

• Mechanism: Abduction + external rotation

Subtypes:

• Inferior (Obturator): flexion + abduction
• Superior (Pubic/Iliac): extension + abduction
• Limb position:
  • External rotation
  • Abduction
  • Mild flexion

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Symptoms and Clinical Presentation

Patients typically present with:

• Severe hip pain
• Inability to move the leg
• Visible deformity

Classic Positions:

• Posterior: shortened, internally rotated limb
• Anterior: externally rotated, abducted limb

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Clinical Evaluation

Because of high-energy trauma, always perform a full trauma assessment.

Important Assessments:

• Neurovascular exam:
  • Sciatic nerve (especially peroneal branch)
• Look for:
  • Pelvic fractures
  • Femur fractures
  • Spine injuries

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Imaging and Diagnosis

Initial Imaging:

• X-ray pelvis (AP view)
• Cross-table lateral view

Key Findings:

• Posterior dislocation → femoral head appears smaller
• Anterior dislocation → femoral head appears larger
• Disruption of Shenton’s line

Advanced Imaging:

• CT scan (post-reduction):
  • Detect fractures
  • Evaluate joint congruency
• MRI (select cases):
  • Labral injury
  • Vascular status of femoral head

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Classification Systems

Posterior Dislocations (Thompson & Epstein)

• Type I → Simple dislocation
• Type II–III → Posterior wall fractures
• Type IV → Acetabular floor fracture
• Type V → Femoral head fracture

Anterior Dislocations (Epstein)

• Type I → Superior
• Type II → Inferior
• Subtypes based on associated fractures

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Emergency Treatment

🚨 Hip dislocation is an orthopedic emergency. Reduction should occur ASAP—ideally within 6 hours.

Delayed reduction (>12 hours) significantly increases risk of osteonecrosis.

Closed Reduction Techniques

Usually performed under general anesthesia or sedation.

Common Methods:

1. Allis Technique (Most Used)

• Patient supine
• Inline traction + gradual hip flexion
• Assistant stabilizes pelvis

2. Stimson Technique

• Patient prone
• Gravity-assisted reduction

3. Bigelow Maneuver

• Less commonly used (risk of complications)

A successful reduction often produces a “clunk” sound.

Open Reduction (Surgery)

Indicated when:

• Closed reduction fails
• Nonconcentric reduction
• Associated fractures
• Femoral neck fracture

Surgical Approaches:

• Posterior (Kocher-Langenbeck)
• Anterior (Smith-Petersen)
• Anterolateral (Watson-Jones)

Post-Reduction Management

• Confirm with imaging (X-ray + CT)
• Assess joint stability

Rehabilitation:

• Stable hip → partial weight bearing for 4–6 weeks
• Unstable → surgical intervention

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Prognosis

• 70–80% good outcomes in simple posterior dislocations
• Worse prognosis with:
  • Delayed reduction
  • Associated fractures

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Complications

1. Osteonecrosis (Avascular Necrosis)

• Occurs in 5–40%
• Risk increases with delayed reduction

2. Post-Traumatic Arthritis

• Most common long-term complication

3. Sciatic Nerve Injury

• Occurs in 10–20%
• Often affects peroneal division

4. Recurrent Dislocation

• Rare (<2%)

5. Heterotopic Ossification

• Occurs in ~2%

6. Thromboembolism

• Requires prophylaxis

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Key Takeaways

• Hip dislocation = medical emergency
• Usually caused by high-energy trauma
• Posterior dislocations are most common
• Early reduction is crucial to prevent complications
• Long-term outcomes depend on timing and associated injuries

References & More

1. Dawson-Amoah K, Raszewski J, Duplantier N, Waddell BS. Dislocation of the Hip: A Review of Types, Causes, and Treatment. Ochsner J. 2018 Fall;18(3):242-252. doi: 10.31486/toj.17.0079. PMID: 30275789; PMCID: PMC6162140. Pubmed
2. Masiewicz S, Mabrouk A, Johnson DE. Posterior Hip Dislocation. [Updated 2023 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: Pubmed
3. Graber M, Marino DV, Johnson DE. Anterior Hip Dislocation. [Updated 2023 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: Pubmed
4. Egol KA. Handbook of fractures. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2019.