Hip Dislocation Flashcards by Mackenzie Pargeon

soft tissue constraints on the hip joint

labrum
capsule
ligamentum teres

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pure dislocation without associated fracture

simple dislocation

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what is a simple dislocation?

pure dislocation without associated fracture

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dislocation associated with fracture of acetabulum or proximal femur

complex dislocation

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what is a complex dislocation

dislocation associated with fracture of acetabulum or proximal femur

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most common direction of dislocation

posterior

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occur with axial load on femur, typically with hip flexed and adducted

posterior dislocation

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posterior dislocation biomechanics

occur with axial load on femur, typically with hip flexed and adducted

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axial load through flexed knee (dashboard injury)

posterior dislocation

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increasing flexion and adduction favors ____ dislocation

simple

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increasing flexion and _____ favors simple dislocation

adduction

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posterior dislocation associations

osteonecrosis
posterior wall acetabular fracture
femoral head fractures
sciatic nerve injuries
ipsilateral knee injuries (up to 25%)

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associated with femoral head impaction or chondral injury

anterior dislocation

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anterior dislocation associated with femoral head impaction or ____

chondral injury

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anterior dislocation associated with ____ or chondral injury

femoral head impaction

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occurs with the hip in abduction and external rotation

anterior dislocation

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anterior dislocation occurs with the hip in _____ and external rotation

abduction

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anterior dislocation occurs with the hip in abduction and ____

external rotation

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anterior dislocation can be further classified as

superior or inferior

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hip extension results in a _____ (pubic) dislocation

superior

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hip _____ results in a superior (pubic) dislocation

extension

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Clinically hip appears in extension and external rotation

superior/anterior dislocation

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flexion results in _____ (obturator) dislocation

inferior

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_____ results in inferior (obturator) dislocation

flexion

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Clinically hip appears in flexion, abduction, and external rotation

inferior/anterior

symptoms

acute pain, inability to bear weight, deformity

____% of dislocations with associated injuries

associated with posterior wall and anterior femoral head fracture

posterior dislocation

hip and leg in slight flexion, adduction, and internal rotation

posterior dislocation

posterior dislocation associated with ____ fracture

posterior wall and anterior femoral head

percentage of posterior dislocations with sciatic nerve injury

10-20%

examine ____ for associated injury or instability

knee

chest X-ray ATLS workup for ____

aortic injury

hip and leg in extension, abduction, and external rotation

anterior dislocation

radiographic views prior to reduction

AP and cross table lateral

used to differentiate between anterior vs. posterior dislocation

cross table lateral

cross table lateral usage

used to differentiate between anterior vs. posterior dislocation

scrutinize ____ to rule out fracture prior to attempting closed reduction

femoral neck

views to obtain after reduction

AP, inlet/outlet, judet views

general radiographic findings:

loss of congruence disruption of shenton's line

arc along inferior femoral neck + superior obturator foramen

shenton's line

what is shenton's line

arc along inferior femoral neck + superior obturator foramen

femoral head appears larger than contralateral femoral head femoral head is medial or inferior to acetabulum

anterior dislocation

radiographic findings of anterior dislocation

femoral head appears larger than contralateral femoral head femoral head is medial or inferior to acetabulum

femoral head appears smaller than contralateral femoral head femoral head superimposes roof of acetabulum decreased visualization of lesser trochanter due to internal rotation of femur

posterior dislocation

posterior dislocation radiographic findings

femoral head appears smaller than contralateral femoral head femoral head superimposes roof of acetabulum decreased visualization of lesser trochanter due to internal rotation of femur

femoral head appears larger than contralateral femoral head

anterior dislocation

femoral head is medial or inferior to acetabulum

anterior dislocation

femoral head appears smaller than contralateral femoral head

posterior dislocation

femoral head superimposes roof of acetabulum

posterior dislocation

decreased visualization of lesser trochanter due to internal rotation of femur

posterior dislocation

helps to determine direction of dislocation, loose bodies, and associated fractures

CT usage

helps to determine direction of dislocation, loose bodies, and associated fractures

post reduction ____ must be performed for all traumatic hip dislocations

post reduction CT must be performed for all _____

traumatic hip dislocations

post reduction CT must be performed for all traumatic hip dislocations to look for

femoral head fractures loose bodies acetabular fractures

useful to evaluate labrum, cartilage and femoral head vascularity

MRI

MRI usage

useful to evaluate labrum, cartilage and femoral head vascularity

non op management

emergent closed reduction within 12 hours

non op indications

acute anterior and posterior dislocations

non op contraindications

ipsilateral displaced or non-displaced femoral neck fracture

operative techniques

open reduction and/or removal of incarcerated fragments ORIF arthroscopy

open reduction and removal of incarcerated fragments indications

irreducible dislocation radiographic evidence of incarcerated fragment delayed presentation non-concentric reduction should be performed on urgent basis

indications for open reduction and removal of incarcerated fragments

ORIF indications

associated fractures of acetabulum femoral head femoral neck

arthroscopy indications

no current established indications potential for removal of intra-articular fragments evaluate intra-articular injuries to cartilage, capsule, and labrum

arthroscopy

closed reduction-perform with patient supine and apply traction in line with _____ regardless of direction of dislocation

deformity

must have adequate sedation and muscular relaxation to perform ____

reduction

assess hip ____ after reduction

stability

post reduction-for simple dislocation, follow with protected weight bearing for _____ weeks

4-6

ORIF approach to posterior dislocation

posterior (Kocher-Langenbeck) approach

ORIF approach to anterior dislocation

anterior (Smith-Petersen) approach

may place patient in traction to reduce forces on cartilage due to ____ or in setting of unstable dislocation

incarcerated fragment

may place patient in traction to reduce forces on cartilage due to incarcerated fragment or in setting of _____

unstable dislocation

complications:

post traumatic arthritis femoral head osteonecrosis sciatic nerve injury recurrent dislocations

post traumatic arthritis incidence

up to 20% for simple dislocation, markedly increased for complex dislocation

incidence of femoral head osteonecrosis

5-40%

femoral head osteonecrosis risk increased with ____

increased time to reduction

sciatic nerve injury incidence

8-20%

Hip Dislocation Flashcards

(80 cards)