Imaging Studies
Radiographs
An anteroposterior (AP) scapular Y or outlet view and axillary view of the shoulder should be obtained when the pain persists after 6 weeks or more of rest and rehabilitation. These radiographs are performed to rule out the much less likely skeletal causes of shoulder pain (eg, stress fracture, infection, tumor) or evidence of prior trauma or instability, such as a loose body, bony Bankart lesion, or Hill-Sachs lesion.
Magnetic resonance imaging (MRI)
If imaging is needed, MRI is the study that is most likely to be helpful for determining the source of injury in swimmer's shoulder. An MRI images the full spectrum of rotator cuff pathology, which is by far the most likely source of pain in swimmer's shoulder, while also depicting the bones, ligaments, and other tendons in the shoulder.
In most cases of swimmer's shoulder, the MRI findings are normal. On occasion, the MRI may demonstrate some increased signal in the substance of the supraspinatus tendon, indicating tendinitis or tendinosis. If fluid is detected in the subacromial bursa, bursitis may be present, along with a partial tear or fraying of the rotator cuff.
If a labral tear is suspected, an MRI arthrogram (MRA) with intra-articular gadolinium is more sensitive and should be considered.
Procedures
Subacromial injection
This can be a useful test in the older swimmer whose condition has failed to respond to rest and rehabilitation, suggesting a partial or complete rotator cuff tear. Termed an impingement test when performed with lidocaine alone, a subacromial injection can be both diagnostic as well as therapeutic when a corticosteroid (eg, methylprednisolone) is added.
Immediate relief of pain following the injection (as evidenced by a negative Neer test result) would suggest an injury of the rotator cuff and/or the overlying bursa. The addition of a corticosteroid to the injection can give the athlete a prolonged period of pain relief, lasting weeks or months, during which time a rotator cuff strengthening program can be instituted.
Intra-articular injection
This can be a diagnostic as well as therapeutic procedure. Injection is within the glenohumeral joint with lidocaine alone or with a corticosteroid (eg, methylprednisolone, triamcinolone). The addition of a corticosteroid to the injection can give the athlete a prolonged period of pain relief if the derangement is intra-articular in nature.
