Traumatic Hip Dislocation in a 3-Year-Old Girl
Emergency closed reduction under sedation/general anesthesia should be performed within 6 hours of injury, followed by immobilization in a hip spica cast for 3-6 weeks, then gradual weight-bearing with close follow-up imaging to monitor for avascular necrosis (AVN).
Immediate Management: Emergency Reduction
The absolute priority is achieving hip reduction within 6 hours of injury to minimize the risk of AVN of the femoral head 1, 2, 3, 4. The risk of AVN increases dramatically when reduction is delayed beyond this critical window 3, 4.
Reduction Technique
- Closed reduction is the first-line approach and is successful in most pediatric cases 1, 2, 4
- Use the Allis maneuver under sedation or general anesthesia 1, 5
- Gentle manipulation is essential—forceful reduction can cause iatrogenic chondrolysis and osteonecrosis 2
- Confirm reduction with fluoroscopy/image intensifier before immobilization 2
Critical caveat: Up to 25% of cases may require open reduction if closed reduction fails or if there is soft tissue/bone interposition 3, 4. Do not persist with multiple aggressive closed reduction attempts.
Post-Reduction Immobilization
After successful reduction, apply a hip spica cast (one and a half or pelvispedious cast) with the hip in approximately 30° abduction 1, 2, 6.
Duration of Immobilization
- 3-6 weeks is the typical immobilization period 1, 2, 6
- In children under 3 years with low-energy trauma, immobilization alone (without preliminary traction) is appropriate 6
- Some protocols use brief skin traction (2 weeks) followed by immobilization 5, but direct immobilization after reduction is acceptable 6
Post-Immobilization Rehabilitation
After cast removal:
- Begin physical therapy with gradual weight-bearing as tolerated 1, 7
- Protected weight-bearing for 2-4 weeks, then progress to full weight-bearing 7
- Most children achieve normal function within 2-3 months 1, 2
Follow-Up Imaging Protocol
This is critical and non-negotiable: AVN can develop months to years after injury and requires systematic surveillance.
Imaging Schedule
- Immediate post-reduction: Plain radiographs to confirm concentric reduction 8
- 6 months post-injury: MRI without contrast to detect early AVN 2, 7
- 12-18 months post-injury: Repeat MRI 2
- Minimum 2 years surveillance: Continue clinical and radiographic monitoring 5
MRI is superior to plain radiographs for early AVN detection, as radiographic changes appear late 2, 7.
Key Distinguishing Features in Young Children
Hip dislocations in children under 3 years differ fundamentally from older children and adults 6:
- Low-energy mechanism: Falls from low heights or minor twisting injuries are sufficient 1, 2, 6
- Predisposing factors: Look for ligamentous laxity, coxa valga, or insufficient acetabular coverage 6
- Easier reduction: Less force required, lower rate of associated fractures 4, 6
- Better prognosis: When reduced promptly, outcomes are generally excellent 1, 2, 6
Clinical Presentation to Confirm
The affected leg will be:
- Shortened
- Adducted and internally rotated (for posterior dislocation—90% of cases)
- Severe pain with any attempted movement
- Limited or absent passive range of motion 1, 2
Complications to Monitor
- AVN of femoral head: Most serious complication, risk increases with delayed reduction beyond 6 hours 3, 4, 7
- Coxa magna: Femoral head overgrowth 4, 6
- Recurrent dislocation: Rare in children 1
- Chondrolysis: Can result from forceful reduction 2, 4
- Late osteoarthritis: Long-term risk 4
The 6-hour window for reduction is the single most important prognostic factor 3, 4, 7. Every effort should be made to achieve reduction within this timeframe, as AVN rates increase substantially with delays.