Hip Dislocation Flashcards
soft tissue constraints on the hip joint
labrum
capsule
ligamentum teres
pure dislocation without associated fracture
simple dislocation
what is a simple dislocation?
pure dislocation without associated fracture
dislocation associated with fracture of acetabulum or proximal femur
complex dislocation
what is a complex dislocation
dislocation associated with fracture of acetabulum or proximal femur
most common direction of dislocation
posterior
occur with axial load on femur, typically with hip flexed and adducted
posterior dislocation
posterior dislocation biomechanics
occur with axial load on femur, typically with hip flexed and adducted
axial load through flexed knee (dashboard injury)
posterior dislocation
increasing flexion and adduction favors ____ dislocation
simple
increasing flexion and _____ favors simple dislocation
adduction
posterior dislocation associations
osteonecrosis
posterior wall acetabular fracture
femoral head fractures
sciatic nerve injuries
ipsilateral knee injuries (up to 25%)
associated with femoral head impaction or chondral injury
anterior dislocation
anterior dislocation associated with femoral head impaction or ____
chondral injury
anterior dislocation associated with ____ or chondral injury
femoral head impaction
occurs with the hip in abduction and external rotation
anterior dislocation
anterior dislocation occurs with the hip in _____ and external rotation
abduction
anterior dislocation occurs with the hip in abduction and ____
external rotation
anterior dislocation can be further classified as
superior or inferior
hip extension results in a _____ (pubic) dislocation
superior
hip _____ results in a superior (pubic) dislocation
extension
Clinically hip appears in extension and external rotation
superior/anterior dislocation
flexion results in _____ (obturator) dislocation
inferior
_____ results in inferior (obturator) dislocation
flexion
Clinically hip appears in flexion, abduction, and external rotation
inferior/anterior
symptoms
acute pain, inability to bear weight, deformity
____% of dislocations with associated injuries
95
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
CT usage
helps to determine direction of dislocation, loose bodies, and associated fractures
post reduction ____ must be performed for all traumatic hip dislocations
CT
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
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
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%
