Common dislocations Flashcards
What are the two most common dislocations?
Shoulder
Knee - patella
What might you expect to see on inspection of a dislocation?
Deformity
What should you palpate for before any intervention on a dislocation?
Blood and nerve supply
By which mechanisms do shoulder dislocations most commonly occur?
Fall
Traction
Seizure
In which directions can a shoulder dislocate?
Anterior
Posterior
Luxatio erecta (i.e inferior)
Who most commonly presents with a shoulder dislocation?
Young adults
Elderly with weakened soft tissues
What is the most common direction for a shoulder to dislocate?
Anterior
By which mechanism does an anterior shoulder dislocation occur?
Fall backwards (shoulder externally rotated)
How must an anterior shoulder dislocation be assessed?
Badge area sensory assessment to rule out compression of the axillary nerve
By which mechanisms does a posterior shoulder dislocation occur?
Fall (shoulder internally rotated)
Direct blow to anterior shoulder
How does a patient with an inferior shoulder dislocation hold their arm?
In abduction
How must an inferior shoulder dislocation be assessed?
Prompt neurovascular assessment and reduction
What is the radiological sign indicating a posterior shoulder dislocation?
Light bulb sign
How is a shoulder dislocation managed?
Closed reduction under anaesthetic
Stabilisation
Rehabilitation
When might a shoulder dislocation be managed with an open reduction?
Fixed posterior dislocations
What is the main predictor of recurrent instability with a shoulder dislocation?
Age - the older the patient is the less likely it is to recur
What are the three main techniques of shoulder reduction?
Hippocratic, kocher’s, in line traction
By which mechanism does an elbow dislocation occur?
Fall onto outstretched hand
Who gets elbow dislocations?
Adults
Children
In which directions can an elbow dislocate?
Anterior
Posterior
Medial
Lateral
What are the associated risks with an elbow dislocation?
Radial head fracture
Coronoid process fracture
By which mechanism does a radial head dislocation commonly occur?
Traction (pulling on the forearm)
Who gets radial head dislocation?
Children and infants
What is the risk for recurrent instability with an elbow dislocation?
Low
How is elbow dislocation managed?
Closed reduction under anaesthetic
2 weeks in a sling
Extensive rehabilitation
Why do elbow dislocations need to undergo rehabilitation?
They are prone to stiffness
How is an elbow dislocation reduced?
Traction in extension +/- pressure over olecranon
By which mechanisms do interphalangeal joint dislocations occur?
Hyperextension
Direct axial blow
In which direction does interphalangeal joint dislocation most commonly occur?
Posterior
What are the associated injuries of a dislocated interphalageal joint?
Phalangeal herniation through volar plate
Associated fracture –> recurrent instability
How are interphalangeal joint dislocations managed?
Closed reduction with digital/metacarpal block
2 weeks in neighbour strapping
How is an interphalangeal joint dislocation managed if it’s unstabled?
Volar slab in edinburgh position
How are interphalangeal joint dislocations reduced?
In line traction with corrective pressure
What is the mechanism of patellar dislocation?
Sudden quadriceps contraction while the knee is bent
What is the direction of patellar dislocation?
Lateral
Who gets patellar dislocation?
Teenagers (girls)
What are the associations with patellar dislocation?
Hypermobility Hypoplastic lateral femoral condyle Increased Q-angle (genu valgum, femoral neck anteversion) Lateral quads insertion Weak vastus medialis
What is typically found on examination on patellar dislocation?
Medial pain
Patellar apprehension test positive
Effusion
What is the cause of the effusion in patellar dislocation?
Haemarthrosis
What is the cause of medial pain in patellar dislocation?
Torn medial retinaculum
How patellar dislocation managed?
Reduction on extension Radiograph Aspirate Brace Physiotherapy
How is repeat patellar dislocation managed?
Surgically - lateral release + medial reefing OR patellar tendon realignment
Are knee dislocations high or low velocity?
Most often high velocity
Can knee dislocations spontaneously relocate?
Yes
Which injuries indicated a knee dislocation that has spontaneously relocated?
Lateral collateral ligament injury
Peroneal nerve injury
Who typically gets knee dislocations?
Teenagers with ligamentous laxity (girls)
What directions can the knee dislocate?
Medial Lateral Rotatory Posterior Anterior
What is the most common direction the knee dislocates?
Posterior
What are the common vascular injuries caused by a knee dislocation?
Popliteal artery
Vein injury
Intimal tear/thrombus
What nerve gets injured with a knee dislocation?
Peroneal injury
How is a knee dislocation monitored for complications?
Normal exam - monitor
Clinical concern - arteriogram or MRI
How is ligamentous injury checked with knee dislocation?
Examination under anaesthetic
How is a knee dislocation managed?
Reduction under anaesthetic
Stabilise in splint/external fixation
When might surgical reduction be required for knee dislocation?
Condyle herniation through capsule
What type of imaging is indicated for knee dislocations and why?
X-rays for associated fractures
MRI
What type of early surgery is indicated for knee dislocations?
Vascular repair
Nerve repair
What type of definitive surgery is indicated for knee dislocations?
Sequential ligamentous repair
What are the possible complications of knee dislocation?
Post-traumatic arthritis and stiffness
Nerve/artery injury
Ligamentous laxity
What is the common mechanisms of hip dislocation?
RTA - dashboard injury
Fall from height
(High velocity)
What is the most common direction of hip dislocation?
Posterior
What are the fractures associated with hip dislocation?
Posterior acetabular wall
Femoral
How does a dislocated hip present?
Flexed
Internally rotated
Adducted knee
How is a hip dislocation managed?
Neurovascular assessment X-ray Urgent reduction Possible stabilisation in-traction Imaging/CT
What nerve is at risk in hip dislocation?
Sciatic
What are the complications of hip dislocation?
Sciatic nerve palsy
Avascular necrosis
Secondary osteoarthritis of the hip
Myositis ossificans
