Common Dislocations Flashcards
what is the most common cause of dislocation?
trauma
where can the shoulder dislocate?
anterior - most common
posterior
inferior - rare
who is shoulder dislocation most common in?
young adults - esp females
what is an anterior shoulder dislocation and what causes it?
humeral head is anterior to the glenoid
caused by fall with shoulder in external rotation
how do you assess axillary nerve?
assess sensation in regimental badge area
- often damaged in anterior shoulder dislocation
what is a posterior shoulder dislocation and what causes it?
humeral head posterior to glenoid
caused by fall with shoulder in internal rotation or direct blow to anterior shoulder
X ray sign of posterior shoulder dislocation?
light bulb sign
what is an inferior shoulder dislocation and what causes it?
humeral head inferior to glenoid
arm held in abduction
what must be done if inferior dislocation of shoulder?
NV assessment and reduction
how is shoulder dislocation managed?
closed reduction under sedation
open reduction
stabilisation and rehabilitation
possible reduction methods?
hippocratic
in line traction
what affects instability of shoulder after dislocation?
age at time of dislocation
- younger = higher risk of instability
what usually causes elbow dislocation?
fall onto outstretched hand
how can an elbow dislocate and who does this usually occur in?
posterior anterior medial lateral occurs in adults and children
risks with elbow dislocation?
radial head or coronoid process fracture
what moves in elbow dislocations?
ulna/radius
- humerus stays the same
what is a pulled elbow?
radial head dislocation/possible elbow dislocation due to arm being pulled upwards
how do you manage elbow dislocation?
closed reduction under sedation
open reduction is rare
2 weeks in sling and rehab
reduction methods in elbow?
traction in extension +/- pressure over olecranon
common mechanism of interphalangeal joints dislocations?
hyperextension injury
direct axial blow
- almost always dislocates posteriorly
possible pitfalls in IP joint dislocation?
head of phalanx button-holes through volar plate
recurrent instability due to associated fracture
how can you assess neurovasculature in the hand/fingers?
cap refill - compare to unaffected finger
assess sensation
how is IP joint dislocation managed?
closed reduction under digital or metacarpal block
open reduction = rare
2 weeks neighbour strapping
volar slab in edinburgh position if unstable
reduction methods for IP joints?
in line traction + corrective pressure
where is anaesthesia applied for finger reduction?
in web space
gives specific numbness only in the finger
what is the edinburgh position?
position of safety
prevents contracture of tendons
what commonly causes patella dislocation and how does it dislocate usually?
sudden quads contraction with a flexing knee
almost always lateral
in teenage girls
what is patella dislocation associated with?
hypermobility
under-developed lateral femoral condyle
increased Q angle (valgus, femoral neck anteversion)
lateral quads insertions or weak vastus medialis
how do you assess Q angle?
line 1 = from ASIS to middle of patella
line 2 = tibial tubercle to middle of patella
angle between lines = Q angle
problems in which structure can predispose to lateral patella dislocation?
medial retinaculum
how does patella dislocation present?
can have medial knee pain clear lateral dislocation often self relocating effusion (haemarthrosis) patella apprehension test +ve
how is patella dislocation managed?
reduce with knee extension radiographs aspiration brace physio surgical if recurrent dislocation - lateral release/medial reefing - patella tendon realignment - replace MPFL with graft
what causes knee dislocation?
high velocity injuries
low velocity injuries - if knee goes back on itself after dislocation
how can a spontaneously relocated knee dislocation injury diagnosed if normal X ray?
lateral collateral ligament injury + fibular nerve injury = dislocation
how can the knee dislocate?
anterior
posterior
rotational, medial, lateral
risk with posterior knee dislocation?
damage to popliteal artery
how is a knee dislocation assessed?
popliteal artery/vein injury (may not be obvious - intimal tear or thrombus)
nerve injury - peroneal nerve
ligamentous stability - examination under anaesthetic
normal exam = observe in hospital
clinical concern = arteriogram/MRI
urgent management of knee dislocation?
reduction under sedation - may need open reduction if condyle button-holed through capsule stabilise in splint or external fixation plain radiographs MRI
early knee dislocation surgery?
vascular repair (6 hr window) nerve repair
definitive knee dislocation surgery? what are the risks with this?
sequential ligamentous repair complications - arthrofibrosis and stiffness - ligament laxity - nerve or arterial injury
what usually causes native hip dislocation? and which direction does it dislocate?
high velocity injury (RTA, fall from height etc)
- usually posterior
what other injuries is hip dislocation associated with?
posterior acetabular wall or femoral fracture
how does hip dislocation present?
hip flexed and internally rotated with knee adducted
early management of hip dislocation?
NV assessment (esp. sciatic nerve) radiographs urgent reduction stabilise in traction if required further imaging (CT)
definitive management of hip dislocation? what are the risks?
fixation of associated pelvic fractures fixation of other injuries in poly-trauma complications - sciatic nerve palsy - avascular necrosis of femoral head - secondary osteoarthritis of hip
