Rotator Cuff Pathology
Patrick St. Pierre
John Gregory Smith published the first detailed series of rotator cuff ruptures, describing seven cases obtained by grave robbing, in a letter to the editor of the London Medical Gazette in 1834. Muller and Perthes were the first to perform repairs in the late 1800s. Codman and later McLaughlin were pioneers in the early 1900s, describing their approach to the shoulder and detailing rotator cuff repair techniques that have been followed until today (9).
In 1972, Charles Neer II (33) first proposed the phrase “impingement syndrome” for pain involving the subacromial bursa and superior rotator cuff. He described the clinical presentation of the painful shoulder and proposed a mechanism for how the pathology developed. He noted that many of these patients had a hooked acromion, and his hypothesis was that the bursa and rotator cuff were impinged between the humeral head and acromion with elevation of the arm. This would usually start as mild inflammation of the tendon, would progress to fibrosis and tendonitis, and eventually could lead to full-thickness rotator cuff tear.
IMPINGEMENT OR ROTATOR CUFF SYNDROME (33,34)
Stage I, as described by Neer, included edema and hemorrhage in the tendon. Tendinosis of the supraspinatus and, less frequently, the infraspinatus or subscapularis is involved.
Stage II consisted of fibrosis and tendonitis in the subacromial space. This is a secondary process resulting from the underlying etiology.
Stage III resulted in the development of spurs and eventually tendon rupture.
The long head of the biceps tendon may also be involved with pathology ranging from inflammation to rupture (12). Dislocation of the biceps tendon from the bicipital groove is pathognomonic for a tear of the upper border of the subscapularis muscle from its humeral insertion (17,18).
Pain will often occur along the anterior-lateral acromion, in the infraspinatus fossa, or distally at the deltoid insertion on the humerus. This pain is likely to be referred pain from the inflamed bursa, which irritates the deep deltoid. Pain referring proximally to the neck usually originates from the acromioclavicular (AC) joint (10,39,41,46).
There have been several other etiologies proposed for shoulder pain emanating from the subacromial space following Dr. Neer’s initial description (23,24,40). These different etiologies may or may not lead to actual impingement of the cuff by the acromion. Because multiple pathologies are often factors in this condition, including tendinosis and bursitis, the best global term to describe this condition is rotator cuff syndrome, reserving impingement syndrome for cases of true external impingement caused by AC arthritis or from the development of a coracoacromial (CA) ligament spur. Specific etiologies, as discussed later, may also be used.
Rotator Cuff Syndrome
Historically, patients will occasionally remember a direct blow or some other form of trauma. There may be history of a traction injury or a fall directly on a patient’s shoulder.
Overuse injury is also a frequent cause of this syndrome. Patients will often not recall a specific injury but may have carried luggage all weekend, cleaned out their attic, or worked on their car. Frequently, repetitive overhead activity such as tennis, softball, or swimming is the causative factor.
These conditions occur primarily because of injury to the rotator cuff causing tendinosis and rotator cuff dysfunction. The subacromial impingement occurs chronically with the development of subacromial spurs and superior humeral head migration due to lower rotator cuff inhibition or fatigue.
Subtle shoulder instability can lead to rotator cuff dysfunction and thus to rotator cuff syndrome. Jobe and colleagues described this as secondary or internal impingement syndrome (23,24). This condition was originally noted in overhead-throwing athletes, but should be suspected in all younger athletes who complain of “impingement”-type pain. Treatment of this condition must address the underlying instability and not just the secondary pathology in the subacromial space.
Posterosuperior Glenoid Impingement
This condition, as described by Walch et al. (40), has also been proposed as an etiology occurring in patients who play repetitive overhead sports such as baseball, tennis, and swimming. Walch did not find the anterior instability described by Jobe in his patients, but rather noted an impingement of the supraspinatus and infraspinatus tendons between the posterosuperior glenoid labrum and the humeral head.
These internal impingement syndromes are characterized by partial tears of the articular surface of the rotator cuff, in distinction to the external compression described by Neer (29).
Whatever the etiology, weakness of the rotator cuff results, especially the lower cuff, and superior humeral head migration occurs. The humeral head then compresses the bursa and tendon into the acromion, leading to impingement. This causes more bursitis, more tendinosis, and eventually more weakness. Often with chronic injury, shoulder mechanics will change, leading to abnormal scapulothoracic motion. Physical therapy will need to include rehabilitation of the scapular stabilizing musculature as well as the lower rotator cuff muscles (25).
Any subacromial changes such as lateral hooking, CA ligament calcification, or AC joint arthritis (inferior spurs), will cause the condition to get worse and will more likely need operative intervention than when the acromion is flat.
The etiology of calcific tendinitis remains unknown. Degenerative changes and relative hypoxia have been suggested as possible explanations. Conservative treatment similar to that for rotator cuff syndrome is reported as successful in 60%-90% of patients (13,20,31). Repetitive needling and injection of local anesthetic have also been successful in relieving symptoms and often result in disappearance of the calcified mass. Infrequently, the patient’s symptoms will persist, and the patient will require operative intervention. The mass is localized within the substance of the tendon while viewing in the subacromial space. The calcified substance is then evacuated and debrided. Some argue that a repair of the tendon is not necessary, but the surgeon should evaluate the cuff after debridement in each case to determine if repair is necessary.
Inspection should focus on normal alignment of chest wall, shoulders, and clavicle. Have the patient perform active range of motion (ROM) in forward flexion, abduction, adduction, external rotation, and internal rotation. Look from the back and front for asymmetric motion or atrophy. Often patients will have a painful arc of motion over 120 degrees of elevation.
Palpate the AC and sternoclavicular joints, the anterior and lateral acromion edges, and the infraspinatus fossa. Tenderness at the AC joint should lead you to further evaluation and treatment of AC joint arthrosis. Cross-arm adduction is often painful with AC arthrosis. However, this test is not very specific and is often positive with rotator cuff syndrome.
Palpation of the long head of the biceps tendon within the bicipital groove is helpful to determine biceps involvement. O’Brien active compression test, Speed test, and Yergason test are also used to determine biceps involvement and are covered in Chapter 50.
Strength testing should involve the deltoid, biceps, and triceps muscles. Although there is no way to totally isolate each of the rotator cuff muscles, the tests that have shown to be most specific are the following (26):
Supraspinatus: Active elevation against resistance with the elbow in extension and the arm elevated to 90 degrees and externally rotated to 45 degrees. The hand should be supinated to neutral as if holding a full can of soda.
Infraspinatus/teres minor: Active external rotation with arm at the side and elbow flexed to 90 degrees.
Subscapularis: Active internal rotation with elbow flexed to 90 degrees and hand placed behind the back. This is often referred to as the Gerber lift-off test (17,18,19). In patients who are unable to internally rotate their hand behind their back, a belly press test or “Napoleon’s test” is performed. The patient places their hand on their belly and presses hard into their abdomen while bringing their elbow forward in the sagittal plane. Subscapularis tear or dysfunction is indicated if they are unable to do this maneuver and the elbow stays close to the side (42).
Lag tests are also often used to detect rotator cuff tears. The hornblower’s sign, external rotation lag, and internal rotation lag tests were described by Gerber and Hertel and are helpful to determine subtle weakness (18,22).
Special tests include the Neer impingement sign and test and Hawkins sign.
The Neer impingement sign is similar to the supraspinatus testing described earlier, except the arm is held in maximal internal rotation as if pouring out a can of soda. This rotates the greater tuberosity under the acromion to elicit a painful response if the bursa or tendons are injured. A positive Neer test is when a subacromial injection of local anesthetic relieves the pain elicited prior to the injection (33,34).
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