Definition

The rotator cuff has three main functions in the shoulder. It compresses the humeral head into the fossa, increases joint contact pressure, and centers the humeral head on the glenoid. Three types of tears can occur to the rotator cuff. A full-thickness tear can be massive and cause immediate functional impairments. Another type of tear, a partial-thickness tear, can be broken down into a tear on the superior surface into the subacromial space or a tear on the inferior surface on the articular side. As a result of a rotator cuff tear, the humeral head will be displaced superiorly during abduction because of the unopposed action of the deltoid. These tears can be either traumatic or degenerative [1–7] (Figs. 17.1 to 17.3).

Traumatic tears occur in the younger population of athletes and laborers, whereas degenerative tears occur in older individuals. One reason that rotator cuff tears are more common in men is because there are more male heavy laborers. The incidence of degenerative tears is increased in both sexes for individuals older than 35 years and for those with chronic impingement syndrome, repetitive microtrauma, tendon degeneration, and hypovascularity [4,6,8].

Symptoms

Symptoms are similar to those of rotator cuff tendinitis. Pain is referred to the lateral triceps and sometimes more globally in the shoulder. There is often coexisting inflammation, and the pain quality is dull and achy. Weakness occurs because of the pain, which is caused by the impaired motion or the tear itself. Persons have difficulty with overhead activities. Patients may report pain at night in a side-lying position.

Physical Examination

Examination is essentially the same as for rotator cuff tendinitis. The most common physical findings of a tear are supraspinatus weakness, external rotator weakness, and impingement. The arm drop test may demonstrate greater weakness than expected from an inflamed, intact tendon, although one can be easily fooled. As with rotator cuff tendinitis, an anesthetic injection into the subacromial space may help discern tear. Even though the pain may be improved or resolved from the injection, resisted abduction will be just as weak because the torn tendon cannot withstand the stress [9].

Remember to examine the cervical spine to avoid missing underlying pathologic changes. A rotator cuff tear develops in some individuals as a result of a radiculopathy or other nerve impairment. The dysfunction of the shoulder from a radiculopathy or suprascapular neuropathy results in weakness of the rotator cuff or the scapular stabilizers. This dysrhythmia causes impingement of the tendons with other structures and eventually leads to fraying and tearing [10–12].

Functional Limitations

The greatest limitation that patients complain of is performing overhead activities [2,7,13–15].

Patients with rotator cuff tendinitis complain of difficulty with overhead activities (e.g., throwing a baseball, painting a ceiling), greatest above 90 degrees of abduction, secondary to pain or weakness. Internal and external rotation may be compromised and may affect daily self-care activities. Women typically have difficulty hooking the bra in back. Work activities, such as filing, hammering overhead, and lifting, will be affected. The patient can be awakened by pain in the shoulder, which impairs his or her sleep.

Diagnostic Studies

The diagnosis of a rotator cuff tear depends mostly on the history and physical examination. However, imaging studies may be used to confirm the clinician’s diagnosis and to eliminate other possible pathologic processes.

Radiographs are often obtained to rule out any osseous problem. A tear can be inferred if there is evidence of humeral head upward migration or sclerotic changes at the greater tuberosity where the tendons insert. Radiographs are helpful with active 90-degree abduction showing a decreased acromiohumeral distance secondary to absence of the supraspinatus and unopposed action of the deltoid.

Magnetic resonance imaging (MRI) of the shoulder is the “gold standard.” [16] Computed tomographic scans show osseous structures better but are less effective at demonstrating a soft tissue injury. By evaluation of the amount of retraction, the clinician is also better able to predict the course of recovery.

As in the evaluation of a person with rotator cuff tendinitis, an anesthetic injection can be performed to differentiate a tear from tendinitis.