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Hip Dislocation

Topic updated on 12/19/13 4:21am
Introduction
  • Epidemiology
    • rare, but high incidence of associated injuries 
    • mechanism is usually young patients with high energy trauma
  • Hip joint inherently stable due to
    • bony anatomy
    • soft tissue constraints including
      • labrum
      • capsule 
      • ligamentum teres
Classification
  • Simple vs. Complex
    • simple
      • pure dislocation without associated fracture
    • complex
      • dislocation associated with fracture of acetabulum or proximal femur
  • Anatomic classification
    • posterior dislocation (90%)
      • occur with axial load on femur, typically with hip flexed and adducted
        • axial load through flexed knee (dashboard injury
      • position of hip determines associated acetabular injury
        • increasing flexion and adduction favors simple dislocation
      • associated with
        • osteonecrosis
        • posterior wall acetabular fracture
        • femoral head fractures
        • sciatic nerve injuries 
        • ipsilateral knee injuries (up to 25%) 
    • anterior dislocation 
      • associated with femoral head impaction or chondral injury
      • occurs with the hip in abduction and external rotation
      • inferior vs. superior
        • hip extension results in a superior (pubic) dislocation
        • flexion results in inferior (obturator) dislocation
Presentation
  • Symptoms
    • acute pain, inability to bear weight, deformity
  • Physical exam
    • ATLS
      • 95% of dislocations with associated injuries 
    • posterior dislocation (90%) 
      • hip and leg in slight flexion, adduction, and internal rotation 
      • detailed neurovascular exam (10-20% sciatic nerve injury)
      • examine knee for associated injury or instability
    • anterior dislocation
      • hip and leg in flexion, abduction, and external rotation 
Imaging
  • Radiographs
    • can typically see posterior dislocation on AP pelvis 
      • femoral head smaller then contralateral side
      • Shenton's line broken
      • lesser trochanter shadow reveals internally rotated limb as compared to contralateral side
      • scrutinize femoral neck to rule out fracture prior to attempting closed reduction
  • CT
    • helps to determine direction of dislocation, loose bodies, and associated fractures
      • anterior dislocation 
      • posterior dislocation 
    • post reduction CT must be performed for all traumatic hip dislocations to look for
      • femoral head fractures 
      • loose bodies 
      • acetabular fractures 
  • MRI
    • controversial and routine use is not currently supported 
    • useful to evaluate labrum, cartilage and femoral head vascularity
Treatment
  • Nonoperative
    • emergent closed reduction within 6 hours
      • indications
        • acute anterior and posterior dislocations
      • contraindications
        • ipsilateral displaced or non-displaced femoral neck fracture
  • Operative
    • open reduction and/or removal of incarcerated fragments
      • indications
        • irreducible dislocation
        • radiographic evidence of incarcerated fragment 
        • delayed presentation 
        • non-concentric reduction
        • should be performed on urgent basis
    • ORIF
      • indications
        • associated fractures of
          • acetabulum 
          • femoral head
          • femoral neck 
            • should be stabilized prior to reduction
    • arthroscopy
      • indications
        • no current established indications
        • potential for removal of intra-articular fragments
        • evaluate intra-articular injuries to cartilage, capsule, and labrum
Techniques
  • Closed reduction 
    • perform with patient supine and apply traction in line with deformity regardless of direction of dislocation
    • must have adequate sedation and muscular relaxation to perform reduction 
    • assess hip stability after reduction
    • post reduction CT scan required to rule out
      • femoral head fractures 
      • intra-articular loose bodies/incarcerated fragments
        • may be present even with concentric reduction on plain films
        • acetabular fractures
    • post-reduction 
      • for simple dislocation, follow with protected weight bearing for 4-6 weeks
  • Open reduction
    • approach
      • posterior dislocation
        • posterior (Kocher-Langenbeck) approach
      • anterior dislocation
        • anterior (Smith-Petersen) approach
    • technique
      • may place patient in traction to reduce forces on cartilage due to incarcerated fragment or in setting of unstable dislocation
      • repair of labral or other injuries should be done at the same time
Complications
  • Post-traumatic arthritis 
    • up to 20% for simple dislocation, markedly increased for complex dislocation
  • Femoral head osteonecrosis
    • 5-40% incidence
    • Increased risk with increased time to reduction
  • Sciatic nerve injury
    • 8-20% incidence
    • associated with longer time to reduction
  • Recurrent dislocations
    • less than 2%

 

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Qbank (2 Questions)

TAG
(OBQ08.200) A 41-year-old female sustains the injury shown in Figure A as a result of a high-speed motor vehicle collision. After a successful attempt at closed reduction in the emergency room using conscious sedation, repeat radiographs show a reduced hip joint. What is the next most appropriate step in treatment? Topic Review Topic
FIGURES: A          

1. Femoral skeletal traction
2. CT scan of hip and pelvis
3. Dynamic fluoroscopic examination under general anesthesia
4. Hip spica dressing
5. Touch down weight bearing mobilization

PREFERRED RESPONSE ▶
TAG
(OBQ07.128) A 30-year-old driver is involved in a motor vehicle collision and sustains the injury shown in Figure A. What is the most likely concomitant injury? Topic Review Topic
FIGURES: A          

1. Right knee meniscus tear
2. Left knee ACL tear
3. Subdural hematoma
4. Right ankle fracture-dislocation
5. Lumbar burst fracture

PREFERRED RESPONSE ▶



Cases

http://upload.orthobullets.com/cases/1270/posterior dislocation hip 9.jpg
HPI - fell from motor cycle 9 months ago, is walking with a limp.Has had no treatment.
poll treatment with limited resourses
9/13/2012
61 responses
5
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Videos

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This video shows the mechanism of an acute hip dislocation in a football player....
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This video demonstrates reduction of a dislocated hip and the placement of a fem...
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Posts

post
Schmidt GL, Sciulli R, Altman GT
J Bone Joint Surg Am. 2005 Jun;87(6):1200-4. PMID: 15930527 (Link to Pubmed)
12/18/2013
65 responses
4
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