Common Dislocations Flashcards
Where are common sites of dislocations?
Elbow, hip, shoulder, IP joints, patella, knee
What are common features of the history and examination in all dislocations?
Trauma = fall, RTA, sports injury, seizure
Inspection for deformity
Palpating = vascular supply, neurology
What are the common mechanics of shoulder dislocations, and what directions can the dislocations go in?
Fall, traction injury, common in young adults
Directions = anterior (most common), posterior, inferior (rare)
What are some features of an anterior shoulder dislocation?
Fall with shoulder in external rotation, humeral head anterior to glenoid, needs regimental badge area sensory assessment (axillary nerve)
What are some features of posterior shoulder dislocations?
Fall with shoulder in internal rotation, direct blow to anterior shoulder, humeral head posterior to glenoid
What are some features of inferior shoulder dislocations?
Arm held in abduction, humeral head inferior to glenoid, needs prompt neurovascular assessment and reduction
What are some management options for shoulder dislocations?
Closed reduction under sedation, open reduction, stabilisation and rehabilitation
Reduction methods = Hippocratic, in-line traction
What is a complication of shoulder dislocations?
Recurrent instability risk = related to age, risk of recurrence decreases with age
How do elbow dislocations arise, and in what direction can it be dislocated?
Mechanism = fall onto outstretched hand
Directions = anterior, posterior, medial/lateral
Occurs in adults and children
What are some risks associated with elbow dislocations?
Small risk of radial head or coronoid process fracture
Low risk of recurrence
How should elbow dislocations be managed?
Closed reduction under sedation, open reduction rarely required, 2 weeks in sling and rehabilitation
Reduction methods = traction in extension +/- pressure over olecranon
What are some features of interphalangeal (IP) dislocations?
Mechanism = hyperextension, direct axial blow
Always displaced posteriorly
What are some complications of IP dislocations?
Head of phalanx button holes through volar plate, recurrent instability due to associated fracture
How should interphalangeal dislocations be managed?
Closed reduction under digital/metacarpal block, open reduction rarely required, 2 weeks in neighbouring strapping, volar slab in Edinburgh position if unstable
What reduction methods can be used to treat IP dislocations?
In-line traction plus corrective pressure
What are some features of patellar dislocations?
Mechanism = sudden quads contraction with a flexing knee
Always displaced laterally
Most common in teenagers, more common in girls
What are some causes of patellar dislocations?
Hypermobility, under-developed (hypoplastic) lateral femoral condyle, increased Q angle, genu valgum, increased femoral neck anteversion, lateral quads insertion or weak vastus medialis
How do patients present with a patellar dislocation?
Clear history of patella dislocating laterally, often self-relocating
What would you expect to find on examination of a patient with patellar dislocation?
Pain medially = from torn medial retinaculum
Effusion = haemarthrosis
Positive patellar apprehension test
How are patellar dislocations treated?
Reduce with knee expansion, radiographs, aspiration, brace, physio
Surgery for repeat dislocations = lateral release/medial reefing, patella tendon realignment
How do knee dislocations occur and who gets them?
Mechanism = high or low velocity injuries
Most common in teenagers, more common in girls
Why are knee dislocations missed, and why is it important that they are discovered?
May spontaneously relocate = lateral collateral ligament or peroneal nerve may be injured in initial dislocation
What should you do in a patient with a normal examination but high clinical suspicion of a knee dislocation?
Observe in hospital and get arteriogram/MRI
What structures may be damaged in a knee dislocation?
Peroneal nerve
Popliteal artery and vein = may not be obvious (intimal tear/thrombus)
How should ligamentous stability be examined in a patient with a knee dislocation?
Under anaesthetic
What is the urgent management for a knee dislocation?
Reduction under sedation, may require theatre reduction if condyle has button-holed through capsule, stabilise in splint or external-fixation
What methods are used to image a dislocated knee?
Plain radiographs, MRI
What surgery can be done for knee dislocations?
Early surgery = vascular repair (6hr window), nerve repair
Definitive surgery = sequential ligamentous repair
What are some potential complications of a knee dislocation?
Arthrofibrosis and stiffness, ligament laxity, nerve or arterial injury
What are some features of a hip dislocation?
Mechanism = RTA dashboard injury, fall from height
Most commonly posteriorly displaced
Associated fractures = posterior acetabulum wall, femoral
How di hip dislocations present?
Flexed, internally rotated and adducted knee
What is the early management of a hip dislocation?
Neurovascular assessment (especially sciatic nerve)
Radiographs (changes can be subtle)
Urgent reduction and stabilise in tractions if needed
Further imaging with CT
What is the definitive management for a hip dislocation?
Fixation of associated pelvic fractures
Fixation of other injuries in poly-trauma patients
What are some complications of hip dislocations?
Sciatic nerve palsy, avascular necrosis of femoral head, secondary osteoarthritis of hip
