To retrospectively evaluate the appearance of lesions of osseous and
soft-tissue structures of the glenohumeral joint on magnetic
resonance (MR) images after first-time traumatic posterior shoulder
MATERIALS AND METHODS
The study was institutional review board approved and HIPAA
compliant, as appropriate, for the four institutions at which the
involved patients were treated. Informed patient consent was
obtained, were applicable. Thirty-six male patients (age range,
15-80 years; mean age, 40.2 years) with clinically documented
first-time traumatic posterior shoulder dislocation were examined
with MR arthrography (18 patients) or conventional shoulder MR
imaging (18 patients). Causes of posterior shoulder dislocation were
electric shock in one patient, seizure in one patient, and trauma in
34 patients. Hill-Sachs lesions, rotator cuff tears, biceps tendon
abnormalities, posterior labrocapsular complex lesions, humeral head
translation, and osseous glenoid version angle were evaluated.
Spearman rank correlation and Student t test analyses were
In 31 (86%) of the 36 patients, a reverse Hill-Sachs lesion was
found. Eleven (31%) patients had a reverse osseous Bankart lesion.
Twelve full-thickness rotator cuff tears were seen in seven (19%)
patients: four supraspinatus tendon, three infraspinatus tendon, and
five subscapularis tendon tears. Six (17%) patients had biceps
tendon abnormalities. Posterior labrocapsular complex tears were
identified in 21 (58%) patients: 10 (48%) with posterior labral
sleeve avulsions and 11 (52%) with reverse Bankart lesions.
Twenty-seven (75%) patients had a retroverted scaphoglenoid angle
(mean, 4.5 degrees ). The mean humeral translation distance relative
to the osseous glenoid fossa was -4.8 mm; in 33 (92%) patients, this
distance was translated posteriorly.
The MR appearance of traumatic posterior shoulder dislocation was
characterized by reverse Hill-Sachs lesions in 86% of patients and
posterocaudal labrocapsular lesions in nearly 60% of patients.
Full-thickness rotator cuff tears were seen in approximately 20% of