Renal impairment: contrast and LMWH dose adjustment
Polypharmacy: drug interaction review with sedation agents
Disposition bias
Lower threshold for inpatient admission due to functional status
Physical therapy assessment before discharge
Social support requirements: home supports, rehabilitation placement
Fall risk assessment and prevention counseling
Pediatrics
Age-specific epidemiology
Rare under age 5 — hip joint stability from cartilaginous acetabulum
Most common ages 4-14 years
Lower energy mechanisms sufficient in children (acetabular retroversion, laxity)
SCFE must be excluded in adolescents before reduction attempt
Unique injury patterns
Greater femoral head vascularity in younger children — lower AVN risk
AVN rate lower in children under 6 years (3%) vs older children (15-25%)
Triradiate cartilage injury may be missed on plain radiograph
Physeal fractures common — Salter-Harris classification applies
Reduction approach in children
General anesthesia preferred over procedural sedation in young children
Ketamine 1-2 mg/kg IV or 4-6 mg/kg IM is acceptable alternative
Same reduction techniques as adults; smaller body size facilitates reduction
Require orthopedic consultation before any reduction attempt
Imaging considerations
MRI preferred over CT in children to avoid radiation
MRI reliable and accurate for posterior hip dislocation assessment in pediatric patients
Ultrasound can confirm reduction in infants and young children at bedside
Post-reduction CT acceptable if MRI not available and intra-articular fragment suspected
Follow-up requirements
Closer AVN surveillance: MRI at 4-6 weeks and 3-6 months
Growth disturbance monitoring in skeletally immature
Non-weight-bearing 3-6 weeks then progressive loading per orthopedic guidance
Background
Epidemiology
Incidence and demographics
Posterior dislocations account for approximately 90% of all traumatic hip dislocations
Anterior dislocations account for approximately 10%
Mean age of affected patients approximately 43 years
Males disproportionately affected due to higher-energy trauma exposure
Mechanisms and settings
Motor vehicle collisions predominate (dashboard mechanism in most)
Sports-related dislocations most common in contact and collision athletes
Recurrence rate approximately 3% for native hip dislocations
Athletes: 33% return to pre-injury sports level, 25% do not return to work
Complications and outcomes
AVN rate approximately 5% for isolated simple dislocations
AVN rate up to 35% with associated acetabular fracture-dislocations
Post-traumatic osteoarthritis develops in approximately 32% at intermediate follow-up
Total hip arthroplasty required in approximately 19% at longer-term follow-up
Sciatic nerve injury in up to 27.5% — predominantly peroneal division
Concurrent ipsilateral knee injury (PCL, meniscus) in approximately 29%
Pathophysiology
Anatomic mechanism of dislocation
Hip flexed and adducted at time of impact — positions femoral head against posterior capsule
Axial loading force transmitted through knee and femoral shaft
Posterior capsule and labrum rupture under extreme load
Femoral head exits posteriorly, may shear acetabular wall
Iliofemoral and ischiofemoral ligaments are typically disrupted
Vascular anatomy and AVN mechanism
Medial femoral circumflex artery (MFCA) is the primary blood supply to femoral head
MFCA runs along the posterior femoral neck — at risk during posterior dislocation
Prolonged dislocation causes vascular occlusion from stretch and compression
Restoration of blood flow is time-dependent: 6-hour window is critical
Retinacular vessels also at risk, particularly with associated neck fracture
Nerve injury mechanism
Sciatic nerve exits below piriformis into gluteal region
Posteriorly displaced femoral head compresses or stretches sciatic trunk
Peroneal division is more susceptible to stretch injury (tethered by fibular head)
Neuropraxia most common (recovers in weeks to months); axonotmesis less common
Associated injury mechanisms
Acetabular posterior wall fracture: shear force as femoral head exits
Femoral head fracture: impaction against acetabular rim during dislocation (Pipkin types)
PCL injury: dashboard mechanism transmits force across knee joint simultaneously
Therapeutic Considerations
Timing as primary determinant of outcome
6-hour window from injury to reduction is the critical threshold
Reduction within 6 hours: 88% excellent/good outcomes
Reduction after 6 hours: 42% excellent/good outcomes
Do not delay for CT imaging unless femoral neck fracture suspected
Sedation selection principles
Propofol produces deeper sedation and greater muscle relaxation, facilitating reduction
Muscle relaxation is the key determinant of reduction success
General anesthesia with paralysis for delayed presentations or failed ED reduction
Adequate sedation prevents forceful manipulation and secondary fracture
Post-reduction CT as standard of care
CT sensitivity for intra-articular fragments is 87.3%
Fragments not removed cause progressive chondral damage and arthritis
Failure to identify fragments risks premature weight-bearing on incongruent joint
ACR Appropriateness Criteria (2024) support post-reduction CT as usually appropriate
Long-term surveillance requirement
AVN may not be radiographically apparent for 2-3 years post-injury
MRI at 4-6 weeks and 6-12 months detects pre-radiographic AVN
Minimum 2-year follow-up period recommended
Early AVN detection enables hip preservation strategies before collapse
Patient Discharge Instructions
copy discharge instructions
Your diagnosis and what happened
Your hip was dislocated — the ball came out of the hip socket
The hip has been put back into place in the emergency department
An X-ray and CT scan confirmed the hip is back in the correct position
Activity restrictions
No weight-bearing on the affected leg — use crutches at all times
Do not bend your hip more than 90 degrees (do not lift your knee above your waist)
Do not cross your legs or turn your foot inward
These restrictions are in place for 4-6 weeks or until told otherwise by your bone specialist
Medications
Take pain medications as prescribed
Take anti-clotting medication (blood thinner) as prescribed — this prevents dangerous blood clots while you cannot walk normally
Do not stop either medication without speaking to your doctor first
Follow-up appointments
Bone specialist (orthopedic surgeon) appointment within 1-2 weeks — this is mandatory
MRI of the hip at 4-6 weeks after injury to check blood supply to the ball of the hip
Long-term follow-up is needed for at least 2 years to watch for complications
Warning signs — return to the emergency department immediately if
Sudden increase in hip pain
Sensation that the hip has "given way" or dislocated again
New numbness, tingling, or weakness in your leg or foot
Foot drop or difficulty lifting your foot
Swelling, redness, warmth, or pain in your calf (possible blood clot)
Shortness of breath or chest pain (possible pulmonary embolism)
Fever over 38.5 C (101.3 F) — possible infection
Skin changes over the hip (redness, wound breakdown if surgery performed)
Long-term outlook
Most people do well with early reduction and proper follow-up
There is a risk of the bone losing its blood supply (avascular necrosis) — this is why MRI follow-up is important
There is also a risk of arthritis developing in the hip joint over the coming years
Your bone specialist will guide you on return to activity and sports
References
Guidelines and key sources
Primary clinical guidelines
ACR Appropriateness Criteria: Acute Hip Pain — 2024 Update (Bartolotta et al., JACR 2025)
ACEP Clinical Policy considerations for procedural sedation in the emergency department
ATLS (Advanced Trauma Life Support) protocol for polytrauma management
Landmark studies and systematic reviews
Kellam P, Ostrum RF — Systematic Review and Meta-Analysis of Avascular Necrosis and Post-traumatic Arthritis After Traumatic Hip Dislocation (Journal of Orthopaedic Trauma, 2016)
Benedick A et al. — Traumatic Hip Dislocation: Pediatric and Adult Evaluation and Management (JAAOS, 2024)
Foulk DM, Mullis BH — Hip Dislocation: Evaluation and Management (JAAOS, 2010)
Lurie BM et al. — Comparing Propofol With Fentanyl and Midazolam for Sedation in Closed Reductions of Traumatic Hip Dislocations (Orthopedics, 2022)
Gottlieb M — Hip Dislocations in the Emergency Department: A Review of Reduction Techniques (Journal of Emergency Medicine, 2018)
Reduction technique sources
Hendey GW, Avila A — Captain Morgan Technique for the Reduction of the Dislocated Hip (Annals of Emergency Medicine, 2011)
Dan M et al. — Rocket Launcher: A Novel Reduction Technique for Posterior Hip Dislocations and Review of Current Literature (EMA, 2015)
Bommiasamy AK et al. — Conscious Sedation Versus Rapid Sequence Intubation for the Reduction of Native Traumatic Hip Dislocation (American Journal of Surgery, 2018)
SNOMED CT concept: traumatic dislocation of hip joint
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