Hip Dislocation

Hip dislocation is a serious orthopedic emergency that occurs when the ball-shaped head of the femur (thighbone) is forcefully displaced from its socket in the acetabulum of the hip bone. This traumatic injury requires immediate medical attention to prevent long-term complications such as avascular necrosis, nerve damage, and chronic instability. Hip dislocations are relatively rare due to the stable nature of the hip joint, making them typically the result of high-energy trauma.

Overview

The hip joint is one of the most stable joints in the human body, formed by the articulation between the femoral head and the acetabulum of the pelvis. This ball-and-socket joint is surrounded by strong ligaments, muscles, and a joint capsule that provide remarkable stability during normal activities. However, when subjected to extreme forces, the femoral head can be displaced from its normal position, resulting in a hip dislocation.

Hip dislocations are classified based on the direction of displacement: posterior dislocations account for approximately 85-90% of all hip dislocations, while anterior dislocations are less common but equally serious. Central dislocations, where the femoral head is driven through the acetabulum, represent a distinct category often associated with acetabular fractures.

This injury represents a true orthopedic emergency requiring prompt reduction within 6-12 hours to minimize the risk of complications. The hip joint's blood supply can be compromised during dislocation, leading to avascular necrosis of the femoral head if treatment is delayed. Additionally, the sciatic nerve may be stretched or compressed, potentially causing permanent neurological deficits.

Most hip dislocations occur in adults aged 16-40 years and are typically associated with high-energy trauma such as motor vehicle accidents. The injury can have devastating long-term consequences if not properly managed, including chronic pain, arthritis, and functional disability.

Symptoms

Hip dislocation presents with distinctive clinical features that are usually apparent immediately after the injury. The symptoms are typically severe and unmistakable, making the diagnosis relatively straightforward in most cases.

Primary Symptoms

  • Hip pain that is severe, constant, and localized to the hip region
  • Leg pain that may radiate down the affected limb
  • Complete inability to bear weight on the affected leg
  • Inability to move the hip joint
  • Obvious deformity of the hip and leg position
  • Shortening of the affected leg compared to the uninjured side

Posterior Dislocation Symptoms

In posterior dislocations (most common), the leg typically appears:

  • Shortened and internally rotated
  • Adducted (pulled toward the midline)
  • Flexed at the hip and knee
  • The patient often holds the knee toward the chest

Anterior Dislocation Symptoms

In anterior dislocations, the leg typically appears:

  • Externally rotated and abducted
  • Extended at the hip
  • The femoral head may be palpable in the groin area

Associated Symptoms

  • Numbness or tingling in the leg or foot (indicating nerve involvement)
  • Weakness in foot dorsiflexion (foot drop)
  • Absence of pulses in the foot (indicating vascular compromise)
  • Swelling and bruising around the hip area
  • Signs of shock if there are other associated injuries

Complications-Related Symptoms

  • Persistent numbness after reduction (sciatic nerve injury)
  • Continued pain weeks to months after injury (possible avascular necrosis)
  • Recurrent instability or giving way of the hip
  • Progressive stiffness and decreased range of motion

It's important to note that hip dislocations are often associated with other significant injuries due to the high-energy mechanism typically required to cause this injury. Healthcare providers will assess for additional fractures, internal bleeding, and other trauma-related complications.

Causes

Hip dislocations result from high-energy trauma that overcomes the substantial stability provided by the hip joint's anatomy. The mechanism of injury typically involves significant force applied to a flexed hip, though the specific direction and position determine the type of dislocation.

Motor Vehicle Accidents

The most common cause of hip dislocations, particularly:

  • Dashboard injuries during frontal collisions
  • Direct impact to the knee with hip flexed (posterior dislocation)
  • Side-impact collisions
  • Motorcycle accidents
  • Pedestrian struck by vehicle

Falls from Height

  • Falls from ladders, scaffolding, or buildings
  • Industrial accidents
  • Falls during rock climbing or mountaineering
  • Parachuting accidents

Sports Injuries

Less common but can occur in high-impact sports:

  • American football (particularly linemen)
  • Rugby
  • Skiing (high-speed falls)
  • Snowboarding
  • Gymnastics (rare but possible)
  • Martial arts with high-impact techniques

Other Traumatic Causes

  • Industrial machinery accidents
  • Construction site injuries
  • Military combat injuries
  • Crush injuries
  • Explosions or blast injuries

Special Circumstances

Certain conditions may predispose to hip dislocation with lower energy trauma:

  • Previous hip surgery or hardware
  • Congenital hip dysplasia
  • Neuromuscular disorders causing muscle imbalance
  • Total hip replacement (prosthetic dislocation)
  • Ehlers-Danlos syndrome or other connective tissue disorders

Mechanism by Type

Posterior Dislocation: Occurs when force is applied to a flexed, adducted, and internally rotated hip, typically during dashboard injuries.

Anterior Dislocation: Results from force applied to an extended, abducted, and externally rotated hip, often during falls or direct trauma.

Central Dislocation: Involves fracture of the acetabulum with the femoral head driven into the pelvis, typically from lateral impact.

Risk Factors

While hip dislocations primarily result from traumatic events, certain factors may increase the likelihood of sustaining this injury or experiencing complications.

Demographic Risk Factors

  • Age: Most common in adults aged 16-40 years (peak activity period)
  • Gender: Slightly more common in males due to higher participation in high-risk activities
  • Occupation: Jobs involving heavy machinery, construction, or high-risk environments

Behavioral Risk Factors

  • Participation in high-impact sports
  • Risky driving behaviors or not wearing seatbelts
  • Abusing alcohol or substance use (increases accident risk)
  • Engaging in extreme sports or activities
  • Working in high-risk occupations without proper safety measures

Medical Risk Factors

  • Previous hip surgery: Increases risk of subsequent dislocation
  • Congenital hip dysplasia: Shallow acetabulum provides less stability
  • Neuromuscular disorders: Conditions affecting muscle control and coordination
  • Connective tissue disorders: Such as Ehlers-Danlos syndrome
  • Total hip replacement: Prosthetic joints have different stability characteristics
  • Previous hip dislocation: Increases risk of recurrent dislocation

Anatomical Risk Factors

  • Hip dysplasia or shallow acetabulum
  • Ligamentous laxity or hypermobility
  • Previous trauma causing structural changes
  • Muscle weakness around the hip joint
  • Leg length discrepancy

Environmental Risk Factors

  • Poor road conditions or weather
  • Workplace hazards and inadequate safety protocols
  • Participation in activities without proper protective equipment
  • High-crime areas with increased violence risk

Risk Factors for Complications

  • Delayed treatment: Increases risk of avascular necrosis
  • Associated fractures: Complicate treatment and recovery
  • Age over 50: Higher risk of complications and poorer outcomes
  • Smoking: Impairs healing and increases infection risk
  • Diabetes: Affects healing and increases infection risk
  • Osteoporosis: Increases fracture risk during reduction

Diagnosis

Diagnosing hip dislocation typically begins with clinical assessment, as the presentation is usually quite obvious. However, comprehensive evaluation is essential to identify associated injuries and plan appropriate treatment.

Clinical Examination

Healthcare providers will assess:

  • Visual inspection: Obvious deformity and leg positioning
  • Range of motion: Severely limited and painful
  • Neurological assessment: Sciatic nerve function testing
  • Vascular examination: Pulses, capillary refill, temperature
  • Associated injuries: Examination of entire body for other trauma

Neurological Testing

Critical to assess sciatic nerve integrity:

  • Foot dorsiflexion strength (deep peroneal nerve)
  • Foot eversion strength (superficial peroneal nerve)
  • Foot plantar flexion (tibial nerve)
  • Sensation over dorsum of foot (deep peroneal)
  • Sensation over lateral foot (superficial peroneal)
  • Sensation over sole of foot (tibial nerve)

Imaging Studies

Plain Radiographs

  • Anteroposterior pelvis: First-line imaging study
  • Lateral hip view: May be difficult to obtain due to pain
  • Judet views: To assess acetabular fractures
  • Post-reduction films: To confirm adequate reduction

Advanced Imaging

  • CT scan: Detailed evaluation of bone anatomy and fractures
  • CT with 3D reconstruction: For complex acetabular injuries
  • MRI: To assess soft tissue damage and early avascular necrosis
  • CT angiography: If vascular injury is suspected

Classification Systems

Thompson and Epstein Classification (Posterior Dislocations)

  • Type I: Simple dislocation without fracture
  • Type II: Dislocation with large posterior acetabular rim fracture
  • Type III: Dislocation with comminuted posterior rim fracture
  • Type IV: Dislocation with acetabular floor fracture
  • Type V: Dislocation with femoral head fracture

Pipkin Classification (Femoral Head Fractures with Dislocation)

  • Type I: Fracture below fovea centralis
  • Type II: Fracture above fovea centralis
  • Type III: Type I or II with femoral neck fracture
  • Type IV: Type I or II with acetabular fracture

Laboratory Studies

May be indicated in polytrauma patients:

  • Complete blood count
  • Basic metabolic panel
  • Coagulation studies
  • Type and crossmatch for blood
  • Urinalysis

Differential Diagnosis

  • Femoral neck fracture
  • Intertrochanteric fracture
  • Acetabular fracture
  • Pelvic fracture
  • Lumbar spine injury
  • Sciatic nerve injury

Treatment Options

Hip dislocation treatment focuses on prompt reduction of the joint, management of associated injuries, and prevention of complications. The urgency of treatment cannot be overstated, as delayed reduction significantly increases the risk of serious complications.

Emergency Management

Initial Assessment and Stabilization

  • Primary trauma survey (ABCDE approach)
  • Pain management with appropriate analgesics
  • Neurovascular assessment and documentation
  • Immobilization of the affected extremity
  • Preparation for urgent reduction

Timing of Reduction

  • Ideal: Within 6 hours of injury
  • Acceptable: Within 12 hours
  • Delayed: Beyond 12 hours (increased complication risk)
  • Emergency reduction indicated for neurovascular compromise

Reduction Techniques

Closed Reduction

First-line treatment when no contraindications exist:

Posterior Dislocation Reduction (Allis Method):

  • Patient supine with adequate sedation/anesthesia
  • Assistant stabilizes pelvis
  • Surgeon flexes hip and knee to 90 degrees
  • Gentle longitudinal traction with slight internal rotation
  • Avoid excessive force

Bigelow Method (Alternative):

  • Hip flexed to 90 degrees
  • Abduction and external rotation
  • Extension while maintaining traction

Anterior Dislocation Reduction:

  • Longitudinal traction in slight flexion
  • Internal rotation and adduction
  • Extension to neutral position

Open Reduction

Indicated when closed reduction fails or is contraindicated:

  • Irreducible dislocation (soft tissue interposition)
  • Associated acetabular fractures requiring fixation
  • Femoral head fractures
  • Neurovascular compromise not resolved after closed reduction
  • Failed closed reduction attempts

Post-Reduction Management

Immediate Post-Reduction

  • Confirmation radiographs to verify adequate reduction
  • Repeat neurovascular examination
  • Assessment of hip stability
  • CT scan to rule out loose fragments
  • Pain management

Immobilization and Weight-Bearing

  • Stable reduction: Early mobilization with protected weight-bearing
  • Unstable reduction: Traction or surgical stabilization
  • Associated fractures: Modified protocols based on fracture pattern
  • Physical therapy initiation within 24-48 hours when appropriate

Surgical Treatment

Indications for Surgery

  • Open hip dislocation
  • Irreducible dislocation
  • Unstable reduction
  • Associated acetabular fractures requiring fixation
  • Femoral head fractures
  • Persistent neurovascular compromise
  • Loose intra-articular fragments

Surgical Approaches

  • Posterior approach (Kocher-Langenbeck): For posterior dislocations and fractures
  • Anterior approach (Smith-Petersen): For anterior dislocations
  • Anterolateral approach: For complex cases
  • Combined approaches: For extensive acetabular reconstruction

Rehabilitation Protocol

Phase I (0-6 weeks)

  • Protected weight-bearing with assistive devices
  • Gentle range of motion exercises
  • Isometric strengthening
  • Prevention of hip flexion beyond 90 degrees
  • Avoidance of internal rotation and adduction

Phase II (6-12 weeks)

  • Progressive weight-bearing as tolerated
  • Active range of motion exercises
  • Strengthening of hip musculature
  • Gait training
  • Proprioceptive training

Phase III (3-6 months)

  • Full weight-bearing activities
  • Advanced strengthening exercises
  • Return to functional activities
  • Sport-specific training if applicable

Complication Management

Avascular Necrosis

  • Serial radiographic monitoring
  • MRI for early detection
  • Core decompression for early stages
  • Total hip arthroplasty for advanced cases

Sciatic Nerve Injury

  • Observation for spontaneous recovery
  • Physical therapy and occupational therapy
  • Ankle-foot orthosis for foot drop
  • Nerve repair or grafting in severe cases

Post-traumatic Arthritis

  • Conservative management with anti-inflammatory medications
  • Physical therapy
  • Intra-articular injections
  • Total hip arthroplasty for end-stage arthritis

Prevention

While hip dislocations primarily result from traumatic events that may be difficult to predict, several preventive measures can reduce the risk of sustaining this serious injury.

Motor Vehicle Safety

  • Seatbelt use: Always wear properly fitted seatbelts
  • Proper seating position: Maintain appropriate distance from dashboard
  • Vehicle maintenance: Ensure airbags and safety systems function properly
  • Defensive driving: Practice safe driving habits
  • Avoid distractions: No texting or phone use while driving
  • Speed limits: Adhere to posted speed limits
  • Weather awareness: Adjust driving for road conditions

Workplace Safety

  • Safety training: Participate in all required safety programs
  • Personal protective equipment: Use appropriate safety gear
  • Fall protection: Use harnesses and safety systems when working at height
  • Machine safety: Follow all operating procedures for equipment
  • Hazard recognition: Identify and report workplace hazards
  • Emergency procedures: Know evacuation and emergency protocols

Sports and Recreation Safety

  • Proper equipment: Use appropriate protective gear for specific sports
  • Training and conditioning: Maintain good physical fitness
  • Technique instruction: Learn proper techniques from qualified instructors
  • Progressive training: Gradually increase intensity and difficulty
  • Rules compliance: Follow sport-specific safety rules
  • Equipment inspection: Regularly check protective gear for damage

Home Safety

  • Fall prevention: Remove tripping hazards and improve lighting
  • Ladder safety: Use proper ladder techniques and have assistance
  • Stair safety: Install handrails and maintain good lighting
  • Emergency preparedness: Have emergency contact numbers readily available

Lifestyle Modifications

  • Avoid excessive alcohol: Abusing alcohol increases accident risk
  • Substance abuse prevention: Avoid drugs that impair judgment
  • Physical fitness: Maintain good muscle strength and balance
  • Risk assessment: Evaluate risks before engaging in activities
  • Medical management: Control conditions that affect balance or coordination

Special Populations

Elderly Individuals

  • Regular exercise to maintain strength and balance
  • Home safety modifications
  • Medication review to avoid drugs that cause dizziness
  • Vision and hearing checks
  • Assistive devices when appropriate

Individuals with Hip Replacements

  • Follow post-operative precautions long-term
  • Avoid extreme hip positions
  • Use assistive devices as recommended
  • Maintain regular follow-up appointments
  • Report any hip instability or recurrent dislocations

High-Risk Workers

  • Comprehensive safety training
  • Regular safety refresher courses
  • Proper use of fall protection systems
  • Emergency response training
  • Regular equipment inspections

When to See a Doctor

Hip dislocation is a medical emergency requiring immediate professional attention. Understanding when to seek emergency care versus routine medical consultation is crucial for optimal outcomes.

Seek Emergency Care Immediately For:

  • Obvious hip deformity: Leg appears shortened, rotated, or positioned abnormally
  • Severe hip or leg pain: Especially after trauma
  • Inability to move the hip: Complete loss of hip motion
  • Inability to bear weight: Cannot put any weight on the affected leg
  • Numbness or tingling: In the leg or foot (indicates nerve involvement)
  • Foot drop: Inability to lift the foot up
  • Absent pulses: In the foot or leg
  • Cold or discolored leg: Signs of circulation problems
  • Open wounds: Near the hip with bone visible
  • Signs of shock: Rapid heart rate, low blood pressure, confusion

Call 911 or Go to Emergency Room If:

  • High-energy trauma has occurred (motor vehicle accident, fall from height)
  • Multiple injuries are suspected
  • Patient cannot be safely transported in a regular vehicle
  • Severe pain prevents any movement
  • Signs of vascular compromise are present
  • Neurological symptoms are evident

Follow-Up Care Situations

Schedule urgent medical attention (within 24 hours) for:

  • Persistent pain after hip dislocation treatment
  • New onset of numbness or weakness
  • Signs of infection at surgical sites
  • Increasing swelling or redness
  • Fever after treatment
  • Inability to perform prescribed exercises
  • Concerns about healing progress

Routine Medical Consultation For:

  • History of previous hip dislocation with new symptoms
  • Chronic hip pain or instability
  • Concerns about hip replacement stability
  • Family history of hip problems
  • Questions about activity restrictions
  • Physical therapy needs

Special Considerations

For Athletes

  • Any hip injury during sports participation
  • Persistent hip pain affecting performance
  • Questions about return to sport after hip injury
  • Preventive evaluation for high-risk sports

For Elderly Patients

  • Lower threshold for seeking medical attention
  • Even minor falls should be evaluated if hip pain persists
  • Changes in mobility or function
  • New onset of hip pain

For Patients with Hip Replacements

  • Any sudden hip pain or instability
  • Feeling of the hip "coming out"
  • Inability to move the hip normally
  • Pain that prevents normal activities

What to Expect During Emergency Treatment

  • Immediate pain assessment and management
  • Neurological and vascular examination
  • X-rays and possibly CT scans
  • Preparation for reduction procedure
  • Discussion of treatment options
  • Potential need for surgery

Remember: Hip dislocations are serious injuries that can have long-term consequences if not treated promptly and appropriately. When in doubt, it's always better to seek immediate medical attention rather than wait for symptoms to worsen.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment of medical conditions. Hip dislocation is a medical emergency requiring immediate professional medical attention.

References

  1. Tornetta, P., & Mostafavi, H. R. (1997). Hip dislocation: current treatment regimens. Journal of the American Academy of Orthopaedic Surgeons, 5(1), 27-36.
  2. Thompson, V. P., & Epstein, H. C. (1951). Traumatic dislocation of the hip: a survey of two hundred and four cases covering a period of twenty-one years. Journal of Bone and Joint Surgery, 33(3), 746-778.
  3. Pipkin, G. (1957). Treatment of grade IV fracture-dislocation of the hip. Journal of Bone and Joint Surgery, 39(5), 1027-1042.
  4. Sahin, V., Karakas, E. S., Aksu, S., Atlihan, D., Turk, C. Y., & Halici, M. (2003). Traumatic dislocation and fracture-dislocation of the hip: a long-term follow-up study. Journal of Trauma, 54(3), 520-529.
  5. Cornwall, R., & Radomisli, T. E. (2000). Nerve injury in traumatic dislocation of the hip. Clinical Orthopaedics and Related Research, 377, 84-91.