Rotator cuff dysfunction does not always isolate the most superior aspect of the shoulder. Pain is the most common reason for presentation in rotator cuff injury, and pain lateral or anterior are the most common sites of pain in all comers.[19] The astute clinician should recognize the different potential sources of pain generators in the shoulder. For example, anterior pain may be indicative of proximal biceps tendon pathologies,[20][21][22] while anterolateral or straight lateral pain may be indicative of subacromial impingement or rotator cuff dysfunction,[5][3] and posterior shoulder pain may include, but not be limited to, degenerative conditions of the shoulder and/or referred pain from the neck.[7][20]

Patients with subacromial impingement will often complain of pain with overhead activities and may also endorse weakness. In one study, >98% of presenting patients had pain as an element of their presentation.[23] Patients may describe pain with overhead activities, feelings of weakness, sleep disturbances, and deep aching of the shoulder.

To examine the shoulder, first inspect the shoulder, as well as the scapula, for any obvious asymmetry. Evaluate for scapular winging or dyskinesia.  There may or may not be wasting about the scapula if rotator cuff pathology is present. To perform a focused examination of the supraspinatus, ask the patient to forward flex the arm. Pain at liftoff or pain at 90 to 120 degrees of active elevation may indicate rotator cuff pathology.

Furthermore, pain during active slow de-elevation of the arm may indicate cuff pathology.[23] Care is necessary to rule out adhesive capsulitis as out as a diagnosis. In this scenario, the clinician should evaluate both active and passive (supine) range of motion. In isolated supraspinatus tendinitis (or rotator cuff syndrome/dysfunction), passive ROM should be full in all planes.[7] 

The neurovascular exam should be normal in patients with isolated rotator cuff dysfunction or tendonitis. Decreased pulsed with overhead arm positioning, radicular or dermatomal sensory abnormalities, or focal weakness outside of the shoulder should raise the evaluator to look for alternate or concomitant diagnoses including cervical radiculopathy, thoracic outlet syndrome, brachial plexopathy, or peripheral nerve compression.

The Hawkins test (90 degrees forward flexion and passive significant internal rotation of the arm) may also recreate acromial contact with the inflamed bursa/tendon creating pain. Furthermore, the Jobe (or empty can) test has the patient hold their arm in 90 degrees of abduction, 30 degrees of forward flexion, and resist a downward force while in the thumbs down position.[24] Pain and/or weakness in this position may indicate supraspinatus pathology.  One can also evaluate the patient is the same manner with a thumbs up (or full can) test to further interrogate the cuff.

Some constellation of positive findings may lead to the diagnosis of subacromial bursitis, external shoulder impingement, or supraspinatus tendonitis. Weakness that is frank or painless may be more indicative of a complete supraspinatus tear, but a lack of this finding does not rule out the diagnosis. 

The initial evaluation of the patient complaining of shoulder pain is variable. Many patients can be diagnosed based on exam and do not require additional workup at the initial presentation. The presence of profound weakness marked swelling, erythema, or deformity should prompt a more aggressive workup. Initial imaging of the shoulder with routine radiographs including an AP, axillary lateral, true AP, and scapular-Y view may help visualize pathology about the shoulder. Furthermore, using a true supraspinatus outlet view instead of a regular scapular-Y view may improve acromial characterization.[25]

The Dutch Orthopedic Association published guidelines for treating what they refer to as subacromial pain syndrome. Their recommendations include early anti-inflammatories, injections for persistent cases, and advanced imaging (MRI) for cases lasting longer than six weeks.[26] MRI will help to quantify any partial or full-thickness tearing, as well as help characterize tendon inflammation. These recommendations may be useful in guiding an algorithmic approach to care.

In cases when the evaluator may be less certain regarding the diagnosis, an MRI of the shoulder without contrast is the best study to characterize the soft tissues. Usually, this is indicated in patients who fail a conservative treatment effort of more than six weeks, who have profound symptoms, or who have an unclear diagnosis.

Secondary impingement, which is usually associated with swimmers or overhead athletes, is a part of the constellation of symptoms of overuse and instability. There are reports regarding athletic patients who have lax shoulders, scapular dyskinesia, and train often. The mainstay of treatment in that population involves rest, physical therapy, and a gradual return to activities. It is a separate entity from degenerative shoulder pathologies and may be on the differential in a younger or more athletic population.[27]

Less than one in every four patients will require surgery even if the condition progresses to a symptomatic full-thickness tear.[28] The vast majority of patients will improve with comprehensive non-operative care, including anti-inflammatories and physical therapy. In a 2017 meta-analysis, physical therapy proved effective, as were NSAIDS (when compared to placebo), for the treatment of subacromial impingement, although the evidence was of low quality.[29] Subacromial injections with a combination of corticosteroids and a local anesthetic may provide some diagnostic and therapeutic benefit for the patient as well.[30]  

Multiple authors have debated the importance of corticosteroids beyond eight weeks.[30] If the patient does go on to need rotator cuff repair, there has been some debate about the effect of corticosteroids pre-operatively effecting the healing potential post-operatively.[31] Baverel et all suggest in their data evaluation that injections with corticosteroids may only cause increased re-rupture rates if injected after surgical repair. With that in mind, a single subacromial injection for patients who do not improve with initial NSAIDs and exercises may provide benefits. Multiple injections without advanced imaging and a discussion of the risks (tendon atrophy) are not a recommendation.

At this time, there is much debate about the surgical treatment of the supraspinatus tendonitis and its associated pathology. Some studies show good improvement with isolated subacromial decompression with or without acromioplasty.[32] Other studies state they see no role for the use of surgical intervention without the presence of a symptomatic rotator cuff tear.[26] At this point, current knowledge discourages the routine use of subacromial decompression and acromioplasty for the treatment of supraspinatus tendonitis without MRI evidence of a tear. However, surgical intervention remains a reasonable consideration and alternative once the patient has exhausted all attempts at non-operative management, and when anatomic risk factors may exist in the presence or absence of significant levels of subacromial/subdeltoid bursitis, in addition to possible partial tears in the rotator cuff tendon(s).

With regards to prognosis, a significant portion of untreated supraspinatus tendonitis may go on to rotator cuff tears. In some patients, these early changes may be subclinical and may not present until the tear has been present for some time. Keener et al. described asymptomatic shoulders with rotator cuff changes visible on ultrasound. He found that a significant portion of these patients had a rotator cuff defect that enlarged and became symptomatic over time.[33] This information about the natural history of tears leads us to believe that patients presenting with rotator cuff tendonitis may benefit from early non-surgical interventions, as mentioned above, to improve their prognosis.  

The differential diagnosis should include subacromial impingement, rotator cuff tear (partial versus full-thickness), bicipital tendonitis, glenohumeral arthritis, acromioclavicular arthritis, adhesive capsulitis, and calcific tendonitis.  Note that many of these occur as a continuum of supraspinatus tendonitis and can occur concomitantly. 

Complications of supraspinatus tendonitis include progression to a rotator cuff tear. Rotator cuff tears were initially described by near to be the produce of untreated impingement secondary to tendon hemorrhage and tendonitis.[6] The literature on tendonitis may also indicate that patients with multiple episodes may progress to surgery and that those patients may have some attrition of the rotator cuff noted at the time of surgery.[34] Keener et al. have discussed this at length in multiple ultrasound-based papers in asymptomatic shoulders.  When subclinical rotator cuff tendinopathy was present in these shoulders, they had a greater than 50% chance of progressing to becoming clinically symptomatic.[33] 

Patient education about proper overhead work techniques may be beneficial. Unfortunately, given the widespread commonality of the disease process, it seems unlikely that the prevention effort would render the disease process eliminated.  With that in mind, educating the patient on the need for non-operative measures, the possibility of progression, and the continuum of options for their shoulders will help them become active participants in their care. 

Managing a patient with supraspinatus tendonitis can be challenging, and requires collaborative interprofessional teamwork, particularly in more complicated cases. The team will include imaging colleagues, nursing, and physical therapy team can help this patient have an optimal outcome. It is pivotal that all team members communicate clearly about their perceived role in the care delivery for the supraspinatus tendonitis patient. The best data to date reports that a therapy-based approach that avoids surgery may be best for the patient.[11] [Level 2] Providing the patient with clear goals, education, and a consistent plan of care should be the goal of the care team. An orthopedic specialty nurse can assist in the examination, coordinate physical therapy, and assist in any surgical intervention that may become necessary. If there is pharmaceutical management, the clinician and nurse can have a pharmacist ensure that dosing is optimal and that there are no drug interactions. These patients may go on to have significant rotator cuff failure and having all portions of the interprofessional care team communicate a perceived any acute change in function is crucial to the patient's outcome. [Level 5]