dislocations Flashcards
(29 cards)
what is the mechanism of shoulder dislocation?
fall, traction, injury
what is the most common shoulder dislocation?
most commonly displaces anteriorly,
caused by fall with shoulder in external
rotation,
humeral head displaced anterior to the glenoid,
axillary nerve = regimental badge area
sensory assessment (axillary nerve can be damaged)
what is a posterior shoulder dislocation?
tend to be people with seizures (usually due to the muscle spasms, not
necessarily the fall), light bulb sign, can also occur in fall with shoulder in internal rotation/direct
bloc to anterior shoulder, humeral head displaces posterior to the glenoid
what is an inferior shoulder dislocation?
RARE, arm held in abduction, humeral head displaced inferior to the
glenoid, needs prompt neurovascular assessment and reduction
what is an associated injury with many shoulder dislocations?
labral tears etc.
management of shoulder dislocation?
closed reduction (not surgical) under sedation
open reduction
stabilisation and
rehabilitation
Reduction methods: hippocratic, in-line traction
Once joint is reduced, need to make sure function fully returns (physio, rehab, may need surgical
operations)
Recurrent instability risk: related to age, risk of recurrence decreases with age
what is the mechanism of elbow dislocation?
Tends to occur in children (holding parents hand - pulled elbow), adults - sporting activities etc.)
Mechanism - usually fall onto outstretched hand
what damage can be caused by an elbow dislocation?
directions - posterior, anterior medial/lateral
Small risk of radial head and coronoid process fractures
Elbow is usually pretty stable due to ligaments and stabilisers
Ante cubital fossa: neurovascular structures
how is an elbow dislocation managed?
closed reduction under sedation, rarely need open reduction, 2 weeks in sling and
rehabilitation
Reduction methods: traction in extension +/- pressure over olecranon
Recurrent instability risk is low!
what is the mechanism of an interphalangeal joint dislocation?
Hyperextension injury, direct axial blow - like a football hitting the finger
- almost always posterior (dorsal)
how is an interphalangeal joint investigated?
Again be aware of any damaged neurovascular structures
Possible pitfalls: head of phalanx button-holes through volar plate, recurrent instability due to
associated fracture
Doing X-rays helps to see if there’s an associated fracture (even if you can clearly see the
dislocation)
how is an interphalangeal joint dislocation managed?
closed reduction under digital/metacarpal block (ring block) - numbs the finger,
then pull it back, so open reduction is really rare, 2 weeks in neighbour strapping, volar slab in
Edinburgh position if unstable
Reduction methods: in-line traction and corrective pressure
Hand kept in this position (rehab) for function - to prevent tendon contraction in an abnormal way
(natural hand position):
what is the first thing to do with a patella fracture?
CONFIRM whether it’s a patella dislocation OR
knee dislocation - very different (has different mechanisms
what is the mechanism of patella dislocation?
sudden quads contraction with a flexing knee
who gets a patella dislocation?
Most common in teenagers (and more common in girls) Associations/causes: hyper-mobility, under-developed (hypoplastic) lateral femoral condyle, increased Q-angle (genu valgum, increased femoral neck anteversion), lateral quads insertions or weak vastus medialis
what else can be injured in a patella dislocation?
Can have torn MPFL (medial patella femoral ligament)
always lateral dislocation and often self-relocating
how is a patella dislocation examined?
pain medially (from torn medial retinaculum),
effusion (haemarthrosis),
positive patella apprehension test
how is patella dislocation managed?
reduce with knee extension, radiographs, aspiration, brace, physiotherapy
if repeat dislocations
surgery:
lateral release/medial reefing,
patella tendon realignment
what is the mechanism of knee dislocation?
Usually high energy (velocity) injuries, can be from low energy injuries
Is there spontaneous relocation? - not a diagnosis to be missed, LCL injury + peroneal nerve
injury = dislocation
If knee is swollen but looks fine on an X-ray and nothing else seems wrong?
knee is reduced,
pulses and sensations are intact), remember to exclude knee dislocation - so OBSERVE (small
tear may get worse, instability etc.
how is a suspected knee dislocation managed?
orthopaedic emergency
Normal exam = observe in hospital, clinical concert = arteriogram/MRI
Check ligamentous stability examinations - may have to do this under anaesthetics
Urgent management: reduction under sedation, may need theatre reduction if condyle buttonholed through capsule, stabilise in splint or external fixation (which is basically just another type
of splint)
what are the possible injuries which can accompany knee dislocation?
Vascular injuries: popliteal artery/vein injury, may not be obvious (intimal tear/thrombus)
Nerve injuries: peroneal nerve
how is a knee dislocation diagnosed?
plain radiographs, there are associated fractures, MRI
What surgery is done for a knee dislocation?
Early - vascular repair (6hr window), nerve repair
Definitive - sequential ligamentous repair
Complications: arthrofibrosis and stiffness, ligamentous laxity, nerve/arterial injury
