HIP FRACTURE-DISLOCATIONS
Thompson-Epstein Classification | Pipkin Fractures | Urgent Reduction
THOMPSON-EPSTEIN CLASSIFICATION
Critical Must-Knows
- 6-hour golden window for reduction - AVN risk increases from 5% (under 6h) to 40%+ (over 12h)
- Thompson-Epstein classification - Type I (simple), Type II-V (with fractures)
- Pipkin classification for femoral head fractures - Type I (below fovea), Type II (above fovea), Type III (+ neck), Type IV (+ acetabulum)
- Sciatic nerve at risk in posterior dislocations (10-20%) - peroneal division most vulnerable
- CT post-reduction mandatory - assess concentric reduction, loose bodies, fractures
Examiner's Pearls
- "Hip fracture-dislocation = true orthopaedic emergency - reduce within 6 hours
- "Thompson-Epstein Type V = Pipkin fracture - use Pipkin classification to guide treatment
- "Posterior wall over 40% = unstable - requires ORIF
- "Pipkin III (head + neck) = disaster - double blood supply insult, high AVN risk
Clinical Imaging
Imaging Gallery
Critical Hip Fracture-Dislocation Exam Points
True Orthopaedic Emergency
6-hour golden window for reduction - AVN risk increases from 5% (under 6 hours) to 40%+ (over 12 hours). This is a true orthopaedic emergency. Reduce as soon as possible, even before CT if needed.
Thompson-Epstein Classification
Type I (simple), Type II (posterior wall), Type III (comminuted wall), Type IV (acetabular floor), Type V (femoral head/Pipkin) - Classification guides treatment. Type V uses Pipkin classification for femoral head fracture management.
Pipkin Classification
Pipkin I (below fovea), Pipkin II (above fovea), Pipkin III (+ neck), Pipkin IV (+ acetabulum) - Fovea is key landmark. Above fovea = weight-bearing = must fix. Below fovea = may excise if small.
Sciatic Nerve at Risk
10-20% sciatic nerve injury in posterior dislocations. Peroneal division most vulnerable. Document nerve function BEFORE and AFTER reduction. Most recover by 2 years.
Hip Fracture-Dislocations - Quick Decision Guide
| Type | Associated Fracture | Treatment | AVN Risk |
|---|---|---|---|
| Type I | None | Urgent closed reduction | 5% (under 6h) |
| Type II | Posterior wall | Reduce, assess wall, ORIF if over 40% | 10-15% |
| Type III | Comminuted wall | Reduce, ORIF posterior wall | 15-20% |
| Type IV | Acetabular floor | Reduce, ORIF acetabulum | 20-25% |
| Type V (Pipkin) | Femoral head | Reduce, Pipkin classification guides | 20-40% |
HIPHip Fracture-Dislocation Features
Memory Hook:HIP: Hour (6-hour window), Injury (high-energy), Pipkin (Type V)!
TYPESThompson-Epstein Types
Memory Hook:TYPES: Type I simple, Type II wall, Type III comminuted, Type IV floor, Type V Pipkin!
PIPKINPipkin Classification
Memory Hook:PIPKIN: Pipkin I below fovea, Pipkin II above fovea, Pipkin III plus neck (disaster), Pipkin IV plus acetabulum!
Overview and Epidemiology
Hip fracture-dislocations are high-energy injuries combining hip dislocation with associated fractures (femoral head, acetabulum, femoral neck). They are true orthopaedic emergencies requiring urgent reduction within 6 hours to minimize AVN risk. The Thompson-Epstein classification guides treatment based on associated fractures.
Mechanism of Injury
Posterior dislocation (90%):
- Dashboard injury: Knee strikes dashboard with hip flexed
- High energy: Motor vehicle accident, fall from height
- Associated fractures: Femoral head (Pipkin), posterior wall, femoral neck
Anterior dislocation (10%):
- Forced abduction: Hip forced into abduction and external rotation
- Less common: Usually lower energy
- Associated fractures: Less common
Central dislocation:
- Acetabular fracture: Medial displacement through acetabulum
- High energy: Usually part of complex acetabular fracture pattern
True Orthopaedic Emergency
Hip fracture-dislocation = true orthopaedic emergency - reduce within 6 hours. AVN risk increases from 5% (under 6 hours) to 40%+ (over 12 hours). Every hour of delay increases AVN risk. Reduce as soon as possible, even before CT if needed.
Epidemiology
- Incidence: 5-10% of hip dislocations have associated fractures
- Age: Peak 20-40 years (high-energy trauma)
- Gender: Male predominance (3:1 ratio)
- Laterality: Usually unilateral
- Associated injuries: Other fractures (20-30%), head injury (10-15%), knee injuries (10-15%)
Anatomy and Pathophysiology
Hip Joint Anatomy
The hip joint:
- Ball-and-socket: Femoral head in acetabulum
- Stability: Bony and ligamentous (labrum, capsule, ligaments)
- Blood supply: MFCA (80%), retinacular vessels, ligamentum teres (under 10%)
- Nerves: Sciatic nerve (posterior), femoral nerve (anterior)
Posterior structures at risk:
- Sciatic nerve: Lies posterior to hip, vulnerable in posterior dislocation
- Peroneal division: Most vulnerable (lateral position)
- Tibial division: Less vulnerable (medial position)
Pathophysiology
Posterior dislocation mechanism:
- Dashboard injury: Knee strikes dashboard with hip flexed
- Force transmission: Posterior force on flexed hip
- Dislocation: Femoral head dislocates posteriorly
- Associated fractures: Femoral head (impaction), posterior wall (shear), femoral neck (rare)
Blood supply disruption:
- Retinacular vessels: Disrupted with displacement
- MFCA: May be stretched or torn
- AVN risk: Increases with time to reduction
- 6-hour window: Critical for blood supply preservation
Associated fracture patterns:
- Femoral head (Pipkin): Impaction or shear fracture
- Posterior wall: Shear fracture from dislocation
- Acetabular floor: Central dislocation pattern
- Femoral neck: Rare but devastating (Pipkin III)
Sciatic Nerve at Risk
Sciatic nerve injury occurs in 10-20% of posterior dislocations. Peroneal division is most vulnerable (lateral position). Always document nerve function BEFORE and AFTER reduction. Most injuries recover by 2 years, but explore if no recovery by 6 months.
Classification Systems
Thompson-Epstein Classification (Posterior)
Type I: Dislocation with no or insignificant fracture
- Simple dislocation
- Treatment: Urgent closed reduction
- AVN risk: 5% (under 6 hours)
Type II: Dislocation with single large posterior wall fracture
- Posterior wall fracture
- Treatment: Reduce, assess wall size, ORIF if over 40%
- AVN risk: 10-15%
Type III: Dislocation with comminuted posterior wall fracture
- Comminuted posterior wall
- Treatment: Reduce, ORIF posterior wall
- AVN risk: 15-20%
Type IV: Dislocation with acetabular floor fracture
- Acetabular floor fracture (unstable)
- Treatment: Reduce, ORIF acetabulum
- AVN risk: 20-25%
Type V: Dislocation with femoral head fracture
- Femoral head fracture (Pipkin)
- Treatment: Reduce, Pipkin classification guides treatment
- AVN risk: 20-40%
Thompson-Epstein classification guides treatment based on associated fractures.
Clinical Assessment
History
Mechanism: High-energy trauma
- Dashboard injury: Motor vehicle accident (posterior dislocation)
- Fall from height: High-energy fall
- Sports: Contact sports, high-impact activities
Symptoms:
- Immediate severe pain
- Inability to bear weight
- Leg deformity (shortening, rotation)
- Numbness or weakness (if nerve injury)
Physical Examination
Inspection:
- Posterior dislocation: Leg shortened, adducted, internally rotated
- Anterior dislocation: Leg externally rotated, abducted
- Deformity obvious
- Swelling (may be minimal initially)
Palpation:
- Tenderness over hip
- Palpable femoral head (posterior or anterior)
- Greater trochanter position abnormal
Range of Motion:
- Severely limited (pain, mechanical block)
- Fixed deformity
Neurovascular Status:
- Sciatic nerve: Assess dorsiflexion, plantarflexion, sensation (first web space, lateral foot)
- Vascular: Distal pulses, capillary refill
- Document BEFORE reduction: Critical for medicolegal and clinical assessment
Clinical Examination Key Point
Document sciatic nerve function BEFORE reduction - critical for medicolegal and clinical assessment. Peroneal division most vulnerable (assess dorsiflexion, first web space sensation). Most injuries recover by 2 years, but explore if no recovery by 6 months.
Associated Injuries
- Femoral head fracture (Pipkin): 10-15%
- Posterior wall fracture: 20-30%
- Acetabular fracture: 10-15%
- Femoral neck fracture: 5-10% (Pipkin III)
- Knee injuries: 10-15% (PCL, patella)
- Other fractures: 20-30%
Investigations
Standard X-ray Protocol
Views: AP pelvis and lateral hip (if possible).
Key findings:
- Dislocation: Femoral head out of acetabulum
- Associated fractures: Femoral head, acetabulum, femoral neck
- Femoral neck fracture: MUST exclude before reduction (risk of displacement)
Pre-reduction X-ray essential - exclude femoral neck fracture before attempting reduction.
Management Algorithm
Management Pathway
Hip Fracture-Dislocation Management
Reduce within 6 hours (golden window). Pre-reduction X-ray to exclude femoral neck fracture. Closed reduction in ED or OR. Document nerve function before reduction.
CT scan mandatory after reduction. Assess concentric reduction, loose bodies, fractures (Pipkin, acetabular, neck). Plan definitive treatment.
If no fractures, observe. Protected weight bearing 6-8 weeks. Monitor for AVN (X-ray at 6, 12 weeks, 1 year).
Type II: ORIF posterior wall if over 40%. Type III: ORIF comminuted wall. Type IV: ORIF acetabulum. Type V: Pipkin classification guides treatment.
Surgical Technique
Posterior Wall Fixation
Indications:
- Posterior wall over 40% (unstable)
- Comminuted wall (Type III)
- Non-concentric reduction
Technique:
- Kocher-Langenbeck approach
- Identify and protect sciatic nerve
- Reduce wall fragments
- Spring plate or buttress plate fixation
- Assess stability with fluoroscopy
Critical: Sciatic nerve at risk - identify and protect before any dissection.
Sciatic Nerve Protection
Sciatic nerve lies directly posterior to hip - at risk during posterior approach. Always identify and protect sciatic nerve before any dissection. Use vessel loops to retract. Avoid excessive retraction. Document nerve function before and after surgery.
Complications
| Complication | Incidence | Risk Factors | Prevention/Management |
|---|---|---|---|
| AVN | 5-40% | Time to reduction, displacement, Pipkin type | Urgent reduction (under 6h), anatomic reduction |
| Sciatic nerve injury | 10-20% | Posterior dislocation, surgical approach | Protect nerve, document function |
| Heterotopic ossification | 20-30% | Surgical approach, delayed reduction | Prophylaxis (indomethacin, radiation) |
| Post-traumatic arthritis | 20-30% | Cartilage injury, AVN, malreduction | Anatomic reduction, early reduction |
| Recurrent dislocation | 5-10% | Instability, inadequate fixation | Secure fixation, assess stability |
AVN
5-40% incidence (depends on timing and pattern):
- Cause: Disruption of blood supply, delayed reduction, displacement
- Prevention: Urgent reduction (under 6 hours), anatomic reduction
- Management: Monitor with X-rays (6, 12 weeks, 1 year), THA if symptomatic
Sciatic Nerve Injury
10-20% incidence:
- Cause: Dislocation itself or surgical approach
- Prevention: Protect nerve during approach, document function
- Management: Observation (most recover by 2 years), explore if no recovery by 6 months
Heterotopic Ossification
20-30% incidence:
- Cause: Surgical approach, delayed reduction, associated injuries
- Prevention: Prophylaxis (indomethacin, radiation)
- Management: Excision if symptomatic (wait for maturity)
Postoperative Care
Immediate Postoperative
- Immobilization: None (early mobilization)
- Weight bearing: Depends on associated fractures
- Simple dislocation: Touch-down weight bearing 6-8 weeks
- With fractures: Non-weight bearing until fractures heal
- ROM: Early hip ROM (immediate)
- PT: Hip ROM, strengthening
Rehabilitation Protocol
Weeks 0-2:
- Touch-down or non-weight bearing (depending on fractures)
- Hip ROM exercises
- Quadriceps and hip strengthening
- Ice and elevation
Weeks 2-6:
- Continue protected weight bearing
- Progressive ROM and strengthening
- Balance and proprioception
Weeks 6-12:
- Progressive weight bearing (if fractures healed)
- Full ROM
- Progressive activity
Weeks 12+:
- Return to sport (when strength and ROM normal)
- Continue monitoring for AVN (X-rays at 6, 12 weeks, 1 year)
Return to Sport
Criteria:
- Full ROM (equal to contralateral)
- Strength greater than 90% of contralateral
- No pain or instability
- Functional testing passed
- No AVN on imaging
Timeline: Usually 6-12 months postoperatively, depending on associated injuries.
Outcomes and Prognosis
Overall Outcomes
Simple dislocation (Type I):
- Success rate: 85-90% (with urgent reduction)
- Functional outcomes: 80-85% return to pre-injury level
- Complications: 10-15% (AVN, HO, arthritis)
With fractures (Type II-V):
- Success rate: 70-85% (depends on fracture pattern)
- Functional outcomes: 70-80% return to pre-injury level
- Complications: 20-30% (AVN, HO, arthritis, nerve injury)
Functional Outcomes
Return to sport:
- Timeline: 6-12 months postoperatively
- Rate: 70-85% return to pre-injury level
- Factors: Associated injuries, AVN, rehabilitation compliance
Functional testing:
- Hip strength: 90%+ of contralateral
- ROM: Full (if no complications)
- No pain or instability
Long-Term Prognosis
AVN risk:
- Type I (under 6h): 5-10%
- Type I (over 12h): 40%+
- Type II-V: 20-40% (depends on timing and pattern)
- Pipkin III: 40-60% (disaster)
Post-traumatic arthritis:
- Type I: 20-30% (at 10 years)
- Type II-V: 30-40% (at 10 years)
- Risk factors: Cartilage injury, AVN, malreduction
Factors Affecting Outcomes
Positive factors:
- Urgent reduction (under 6 hours)
- Simple dislocation (Type I)
- No associated fractures
- Complete rehabilitation
Negative factors:
- Delayed reduction (over 12 hours)
- Associated fractures (Type II-V)
- Pipkin III (head + neck)
- Incomplete rehabilitation
Prevention and Return to Sport
Prevention
Primary prevention:
- Seatbelt use (prevents dashboard injury)
- Airbag deployment
- Safe driving practices
- Protective equipment in sports
Secondary prevention (after injury):
- Complete rehabilitation before return to sport
- Continued strength and conditioning
- Gradual return to activity
Return to Sport Criteria
Clinical:
- Full ROM (equal to contralateral)
- Strength greater than 90% of contralateral
- No pain or instability
- No AVN on imaging
Functional:
- Single-leg hop test (greater than 90% of contralateral)
- Agility testing passed
- Sport-specific drills completed
Timeline: Usually 6-12 months postoperatively, depending on associated injuries and AVN risk.
Evidence Base
6-Hour Golden Window
- AVN risk increases from 5% (under 6 hours) to 40%+ (over 12 hours)
- 6-hour golden window for reduction
- Every hour of delay increases AVN risk
Thompson-Epstein Classification
- Original classification system for posterior hip dislocations
- Type I (simple), Type II-V (with fractures)
- Classification guides treatment
Pipkin Classification
- Original classification for femoral head fractures
- Pipkin I-IV classification
- Fovea is key landmark
Sciatic Nerve Injury
- Sciatic nerve injury occurs in 10-20% of posterior dislocations
- Peroneal division most vulnerable
- Most injuries recover by 2 years
Posterior Wall Stability
- Posterior wall over 40% = unstable, requires ORIF
- Wall 20-40% = may be stable, assess with EUA
- Wall size determines stability
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Posterior Dislocation with Pipkin II
"A 30-year-old man presents to ED after a motor vehicle accident. He was the driver and his knee struck the dashboard. He has a painful hip and cannot move his leg. Examination shows leg shortened, adducted, and internally rotated. X-ray shows posterior hip dislocation. After urgent closed reduction, CT shows a Pipkin II femoral head fracture (fragment above fovea, weight-bearing surface)."
Scenario 2: Type II with Posterior Wall
"A 35-year-old athlete presents after a high-energy fall. He has a posterior hip dislocation with a large posterior wall fracture. After urgent closed reduction, CT shows posterior wall fracture involving 45% of the wall. Examination under anesthesia shows instability."
MCQ Practice Points
Golden Window
Q: What is the golden window for hip dislocation reduction? A: 6 hours - AVN risk increases from 5% (under 6 hours) to 40%+ (over 12 hours). This is a true orthopaedic emergency. Reduce as soon as possible.
Thompson-Epstein Type V
Q: What does Thompson-Epstein Type V indicate? A: Femoral head fracture (Pipkin) - Type V = dislocation with femoral head fracture. Use Pipkin classification (I-IV) to guide treatment of the head fracture.
Pipkin II Treatment
Q: What is the treatment for Pipkin II femoral head fracture? A: ORIF with headless screws - Pipkin II = fragment above fovea (weight-bearing surface). Must fix to restore articular surface. Anterior approach to avoid posterior blood supply.
Posterior Wall Threshold
Q: What posterior wall size requires ORIF? A: Over 40% - Posterior wall over 40% = unstable, requires ORIF. Wall 20-40% = may be stable (assess with EUA). Wall under 20% = usually stable.
Sciatic Nerve Injury
Q: What is the incidence of sciatic nerve injury in posterior hip dislocations? A: 10-20% - Peroneal division most vulnerable (lateral position). Most injuries recover by 2 years. Document nerve function before and after reduction.
Pipkin III
Q: Why is Pipkin III (head + neck fracture) considered a disaster? A: Double blood supply insult - Both femoral head and neck blood supply disrupted. Very high AVN risk (40-60%). Often requires THA, even in young patients.
Australian Context
Clinical Practice
- Hip fracture-dislocations true orthopaedic emergencies
- Urgent reduction within 6 hours standard
- CT post-reduction mandatory
- Multidisciplinary approach (orthopaedics, trauma, vascular)
Healthcare System
- Public hospitals handle most cases through trauma networks
- Private insurance covers procedures
- Physiotherapy accessible through public/private
Orthopaedic Exam Relevance
Hip fracture-dislocations are a common viva topic. Know that this is a true orthopaedic emergency (6-hour window), Thompson-Epstein classification (Type I-V), Pipkin classification for Type V (I-IV), posterior wall threshold (40%), sciatic nerve at risk (10-20%), and urgent reduction technique. Be prepared to discuss surgical approaches and complications.
HIP FRACTURE-DISLOCATIONS
High-Yield Exam Summary
Key Anatomy
- •Hip joint: Ball-and-socket, femoral head in acetabulum
- •Sciatic nerve: Posterior to hip, vulnerable in posterior dislocation
- •Blood supply: MFCA 80%, retinacular vessels, ligamentum teres under 10%
- •Fovea: Key landmark for Pipkin classification (above vs below)
Classification
- •Thompson-Epstein: Type I (simple), Type II (wall), Type III (comminuted), Type IV (floor), Type V (Pipkin)
- •Pipkin: I (below fovea), II (above fovea), III (+ neck), IV (+ acetabulum)
- •By timing: Acute (under 6h), Subacute (6-12h), Delayed (over 12h)
- •Posterior wall threshold: over 40% = unstable = ORIF required
Treatment Algorithm
- •Urgent closed reduction within 6 hours (golden window)
- •Post-reduction CT mandatory (assess reduction, fractures, loose bodies)
- •Type I: Observe, protected weight bearing 6-8 weeks
- •Type II-V: Address fractures (ORIF wall, Pipkin, acetabulum)
Surgical Pearls
- •Kocher-Langenbeck approach for posterior, protect sciatic nerve
- •Anterior approach for Pipkin (preserves blood supply)
- •Posterior wall over 40% = unstable = ORIF required
- •Pipkin II = weight-bearing = ORIF required
Complications
- •AVN: 5-40% (depends on timing - under 6h = 5%, over 12h = 40%+)
- •Sciatic nerve injury: 10-20% (most recover by 2 years)
- •Heterotopic ossification: 20-30% (prophylaxis with indomethacin)
- •Post-traumatic arthritis: 20-30% (at 10 years)