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Shoulder Instability Pt 2 - Coggle Diagram
Shoulder Instability Pt 2
Load-shift test: GH translation
reduction important b/c HH may be resting in subluxed position
SN/SP of common shoulder instability tests Pg 343
load-shift (under anesthesia): SN 83%, SP 100%
Sulcus sign: not reported (?)
Apprehension: SN 57%, SP 100%
relocation test: SN 30%, SP 50%
anterior release/surprise: SN 92%, SP 89%
M & IGHL/PC: not reported (?)
grading system to assess GH translation
Grade 1: HH moves to glenoid rim, but not over (up to 50% translation
Grade 2: HH can move over edge of rim, but moves back upon release (>50% translation)
Grade 3: HH remains dislocated on release, corresponding to clinical dislocation
25% anterior translation or less is normal so created grading systerm
anterior release/surprise test
tests for posterior instability: load-shift test, jerk test
radiologic studies and views best suited for confirming or evaluating shoulder instability
Trauma series:
-true AP
-true scapular lateral view
-axillary view
most common views include AP in IR/ER, true AP, Y view (scapulolateral view), axillary view, west point projection, stryker notch view
hill sachs and reverse hill sachs lesions
hill-sachs: compression fracture of of PL aspect of HH. Results from impact on anteriorinferior rim
reverse hill-sachs: complression fracture of anteriormedial HH as result of post dislocation
suggested radiologic view to visualize hill-sachs lesion: IR or stryker notch view
-each has 92% SN
important prognostically, bc HS may be prone to redislocation
bankart lesion
avulsion or detachment of anterior portion of IGHL complex and glenoid labrum off anterior rim
-can lead to increased translation of humeral head
complete dislocation requires associated capsular injury
can contribute to recurrent instability
clinical presentation of post shoulder dislocation
-traditionally hold arm in sling position (adduction and IR)
-often difficult to visualize
-ER usually limited
-not uncommon to find shoulder locked in IR due to lesser tuberosity fracture
-flattened anterior aspect of shoulder
-prominent coracoid process
suggested initial treatment for anterior shoulder dislocation
ice and sling use
early and gentle relocation for acute dislocation important bc it quickly reduces stretch and compression of neurovascular structures, minimizes degree of muscle spasms, prevents progressive enlargement of HH defect in locked dislocation
-post reduction management is controversial: no difference in recurrence rates in immobilized vs non-immobilized
-position of immobilization is also controversial: study showed recurrence rated of 0% when immobilized in ER, compared to 30% in IR at 15.5 months for traumatic anterior dislocation
-still more customary to immobilize in IR
most common complication is recurrence
other complications include fracture of humerus, vascular injuries, neural injuries, RC tears (more common in those >40 y.o.
what accounts for high incidence?
age: under 20, recurrence rate is up to 80%. >40 y.o. recurrence rate drops to under 10%
males > females
most recurrences seen within 2 years of initial traumatic dislocation
varies inversely with severity of initial trauma
if dislocation occurs second time in younger patients, chance of frequent recurrence is 100%
incidence of associated RC tears in patient's greater than 40 y.o.
-ranges from 35 to 86%
-variability due to unknown amount of RC pathology prior to initial dislocation
in younger patients anterior capsuloligamentous structures disrupted because it is less strong that other tissues in shoulder
in older patients posterior structures (RC and greater tuberosity complex) are weaker by attrition and tend to disrupt leaving anterior capsuloligamentous structures intact