Epidemiology
Anterior shoulder dislocation is the commonest dislocation in the body • Makes up 95% of shoulder dislocations • It occurs in around 2% of individuals at some stage • Dislocation is more common in the dominant limb • In young people it is much more common in males • By the 6th to the 7th decade it is more common in females • Instability is bilateral in around 15%
Conceptualizing instability
Two acronyms are used to think about shoulder instability: 1. TUBS: traumatic unidirectional dislocations with a Bankart lesion, often require surgery. 2. AMBRI: Atraumatic multidirectional bilateral shoulder instability, often responds to rehabilitation and occasionally inferior …show more content…
Pathology
Detachment of the anterior labrum and anterior rim of the glenoid – Bankart lesion (IGHL avulses from glenoid)
Indentation on postero-lateral aspect of humeral head – Hill-Sachs lesion
Humeral Avulsion of GlenoHumeral Ligament (HAGL) (IGHL avulses from humerus)
Stretching of inferior glenohumeral ligaments +/- plastic deformation of capsule
There is further damage to the soft tissues with each dislocation
• risk factors for recurrence (Hovelius, 25 year follow up)
b. age (< 25: 40% risk, > 25: 20% risk)
c. sex, activity and sling did not make a difference
d. greater tuberosity fracture reduces risk
e. note: 20% of recurrent dislocators stabilized spontaneously
f. other factors: size of Hills Sachs, Bankart, capsular tear, rotator cuff tear • up to 90% recurrence in 25% need augmentation procedure) • glenoid version • MRI +/- gadolinium • Bankart lesion: look at anterior inferior glenoid on axial T2, proton density films • capsular stripping, redundancy • cuff