MRI findings associated with luxatio erecta humeri.

OBJECTIVE: Luxatio erecta humeri is a rare type of inferior glenohumeral dislocation with a unique radiographic appearance; however, the magnetic resonance imaging findings associated with this dislocation have not been described in the radiology literature. The purpose of this study is to identify magnetic resonance imaging findings associated with this uncommon type of glenohumeral dislocation.
MATERIALS AND METHODS: The magnetic resonance imaging features of four patients with clinical and radiographic evidence of luxatio erecta humeri were reviewed retrospectively by two musculoskeletal-trained radiologists. The reported mechanism of injury in all four patients was falling. The MR imaging examinations were evaluated for the presence of rotator cuff and biceps tendon pathology, glenoid labrum pathology, joint capsule and glenohumeral ligament injury, fractures and bone marrow contusions, articular cartilage injury, and joint effusions.
RESULTS: All four patients demonstrated pathology of the glenohumeral joint. Three of the four patients demonstrated rotator cuff tears, including large full thickness tears of the supraspinatus and infraspinatus tendons in two patients, and small full thickness tear of the supraspinatus tendon with partial thickness tear of the infraspinatus tendon in the third patient. In the two patients with large full thickness tears of the supraspinatus and infraspinatus tendons, one patient demonstrated tearing of the subscapularis tendon with dislocation of a partially torn long head of the biceps tendon, and the second patient demonstrated full thickness tearing of the intra-articular biceps tendon. All four patients demonstrated injuries to the glenoid labrum and both anterior and posterior bands of the inferior glenohumeral ligament. Contusions or fractures of the humeral head were seen in two of the patients. Three of the four patients demonstrated cartilage abnormalities including a focal cartilage defect in the anterior inferior glenoid in one patient, and cartilage surface irregularity of the glenoid in the other two patients.
CONCLUSION: Common magnetic resonance imaging findings in patients with a prior luxatio erecta humeri dislocation include rotator cuff tears, injury to the glenoid labrum, and injury to both the anterior and posterior bands of the inferior glenohumeral ligament. These findings are compatible with the mechanism of dislocation in luxatio erecta, and noting these findings on magnetic resonance imaging may suggest that the patient has sustained a prior inferiorly directed glenohumeral dislocation such as luxatio erecta.