Case of the Week year old male fell on the ice. Presents with shoulder pain and limited ROM

Below are the routine radiographs taken shortly after the accident. What are the abnormal findings? What is the imaging diagnosis? What associated injuries should be investigated?

ANSWERS ABNORMAL FINDINGS: The humeral head is no longer in contact with the glenoid fossa and lies inferomedially. A sharp bony fragment is noted above the greater tuberosity of the humerus. A small, oval,calcific density is present immediately superior to the lateral aspect of the humeral head IMAGING DIAGNOSIS: Anterior dislocation of the proximal humerus. New fracture of the distal aspect of the coracoid process. Probable pre-existing calcific tendinitis. ASSOCIATED INJURIES: Commonly associated injuries with anterior shoulder dislocations that should be carefully evaluated include: 1. Avlusion of the greater tuberosity of the humerus (flap fracture) (not present in this case). 2. Bankart lesions (avulsion of the inferior glenoid labrum, with or without associated avulsion of the inferior glenoid itself.) This often needs MRI. 3. Hillsachs deformity, AKA hatchet defect of the posterior aspect of the humeral head due to impaction with the rim of the glenoid fossa. (Need additional imaging to diagnosis this. Once relocated, the AP with internal rotation view should usually show it.) 4. Injury to the neurovascular bundle.

Below are selected CT slices post-reduction with contrast injected into the joint. Note the nicely seen avulsion of the coracoid process on this axial slice The calcific density in the biceps tendon is nicely shown on this axial slice The impaction fracture in the posterolateral aspect of the humeral head is easily seen on the coronal oblique slice (left) and the sagittal oblique slice (right). This is the classic ‘Hillsachs’ deformity or ‘Hatchet defect’.