Humeral avulsion of the anterior shoulder stabilizing structures after anterior shoulder dislocation: demonstration by MRI and MR arthrography.
OBJECTIVE
To demonstrate the MRI findings of an anterior shoulder capsular avulsion from the humerus, with or without subscapularis rupture, after anterior dislocation or severe abduction external rotation injury.


METHODS
We retrospectively reviewed the MRI and MR arthrographic examinations of seven patients who were identified at surgery with avulsion of the anterior shoulder stabilizers from the humerus. MRI was correlated with clinical history and surgical results.


RESULTS
MRI findings included: inhomogeneity or frank disruption of the anterior capsule at the humeral insertion (all), fluid intensity anterior to the shoulder (six patients), tear of the subscapularis tendon (six patients), dislocation of the biceps tendon (four patients), and a Hill-Sachs deformity (four patients). MR arthrography additionally found extravasation of contrast through the capsular defect (two patients).


CONCLUSIONS
Our findings suggest that MRI is helpful for diagnosing humeral avulsion of the anterior glenohumeral capsule, especially when a tear of the subscapularis tendon insertion is present. MR arthrography may be of benefit for diagnosing capsular avulsion without associated subscapularis tendon abnormality.
Tirman
P F
PF
San Francisco Magnetic Resonance Center, CA 94118, USA.
Steinbach
L S
LS
Feller
J F
JF
Stauffer
A E
AE
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D017746:Joint Capsule / Q000293:injuries*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D000070636:Rotator Cuff Injuries; D012782:Shoulder / Q000473:pathology; D012783:Shoulder Dislocation / Q000150:complications* / Q000175:diagnosis*; D012785:Shoulder Joint / Q000473:pathology; D013708:Tendon Injuries / Q000175:diagnosis* / Q000209:etiology