Shoulder and Elbow cases rotator cuff tear

A 76-year-old, right-hand-dominant man presents to clinic complaining of right shoulder pain. The pain started several months ago, has gotten progressively worse, and is located diffusely over his deltoid region. He has night pain and pain with overhead activity. On examination, there is no visible muscle atrophy, and he has full passive and near full active range of motion. He experiences pain and some weakness with resisted shoulder forward flexion and abduction.

What is the most likely diagnosis?

1. Acromioclavicular joint arthritis

2. Full-thickness rotator cuff tear

3. Adhesive capsulitis

4. Glenohumeral labral tear

5. Partial-thickness rotator cuff tear

 

Discussion

The correct answer is (E). Chronic, degenerative rotator cuff tears are very common in older patients. They usually present with insidious onset of diffuse pain over the deltoid that can radiate partially down the upper arm or into the trapezius. This pain is exacerbated with overhead activities, and night pain is common, which is a predictor of poor outcome with nonoperative treatment. These tears are thought to be the result of a combination of chronic impingement and rotator cuff degeneration from normal aging. The physical examination findings in this case are typical of rotator cuff tears and will be discussed more extensively below.

The scenario given is not one of the acromioclavicular (AC) joint arthritis

(Answer A), which would manifest as pain localized directly at the AC joint, especially with palpation and cross-body adduction testing during examination. Classically, when asking a patient with shoulder pain to localize the pain, if he has AC joint arthritis, he will point with one finger directly over the AC joint. If he has a rotator cuff tear, he will take his hand and lay it over the deltoid due to the diffuse nature of the pain.

Differentiating between partial- and full-thickness tears (Answer B) on examination is difficult, but in general, if a patient is able to flex his or her shoulder through a full or nearly full active range of motion, the tear is not full thickness. A full-thickness tear would generally be associated with significantly decreased active range of motion because the rotator cuff is not able to actively move and stabilize the glenohumeral joint. With a partial-thickness tear, there is still continuous rotator cuff muscle that is able to move and stabilize the shoulder. There is usually not significant weakness with resisted active shoulder flexion but there is pain with it. Other signs of chronic full-thickness tears include weakness, visible atrophy of cuff musculature, and other findings depending on the location of the tear. These signs are almost never seen with partial-thickness tears. With the patient in this case, the physical examination findings are not severe enough to make one suspect a full-thickness tear, so it is more likely that he has a partial-thickness tear.

Adhesive capsulitis (Answer C) causes diffuse shoulder pain with restriction of active and passive range of motion. This patient has near full range of motion of his shoulder.

A labral tear (Answer D) does not classically present with the signs or symptoms seen in this case. Labral tears usually occur acutely with a compression or distraction injury, are associated with mechanical symptoms like clicking and catching, and are diagnosed clinically with different physical examination maneuvers than those for rotator cuff tears.

In the general population, what is the most commonly torn rotator cuff muscle?

1. Supraspinatus

2. Infraspinatus

3. Teres minor

4. Subscapularis

5. Teres major

 

Discussion

The correct answer is (A). It has been shown that it is the most commonly torn

tendon, likely as the result of anatomic, vascular, and biomechanical factors. None of the other rotator cuff tendons, the infraspinatus, teres minor, or subscapularis (Answers B–D) tear as often as the supraspinatus. The teres major (Answer E) is not part of the rotator cuff.

What physical examination maneuver best tests for a supraspinatus tear?

1. Belly press test

2. Hornblower test

3. Jobe test

4. Lift-off test

5. External rotation lag

 

Discussion

The correct answer is (C). Each RC tendon has specific tests for pathology. The supraspinatus strength test (aka Jobe test) is performed by abducting the shoulder to

90 degrees, bringing the arm in the scapular plane (30 degrees forward), and maximally internally rotating the arm (thumb pointing to the floor) (Fig. 2–1). The test is positive if weakness is found or if pain is experienced. Another test for the supraspinatus is the drop arm test. In the drop arm test, the arm is passively elevated by the examiner to the Jobe position, the patient is asked to attempt to keep it there, and the arm is released by the examiner. The test is positive if the patient is not able to keep the arm elevated and the arm drops.

 

 

 

Figure 2–1 Jobe test.

The belly press test (Answer A) and lift off test (Answer D) are used to evaluate for subscapularis pathology (Figs. 2–3 and 2–4). The hornblower test (Answer B) assesses the teres minor (Fig. 2–2). The external rotation lag test (Answer E) evaluates the infraspinatus.

 

 

 

Figure 2–2 Positive hornblower’s sign. (From Kuzel BR, Grindel S, Papandrea R, Ziegler D. Fatty infiltration and rotator cuff atrophy. J Am Acad Orthop Surg. 2013;21(10):613–623.)

 

 

 

Figure 2–3 Positive lift-off test with the patient’s left arm in the right picture. Negative lift-off test with the patient’s right arm in the left picture. (From Lyons RP, Green A. Subscapularis tendon tears. J Am Acad Orthop Surg. 2005;13(5):353–363.)

 

 

Figure 2–4 Positive belly-press test with the patient’s left arm in the right picture. Negative belly-press test with the patient’s right arm in the left picture. (From Lyons RP, Green A. Subscapularis tendon tears. J Am Acad Orthop Surg. 2005;13(5):353–363.)

 

What radiologic test should be used to confirm the diagnosis in this patient?

1. Shoulder CT

2. Shoulder MRI

3. Shoulder roentgenogram

4. Shoulder arthrogram

5. Shoulder MR arthrogram

 

Discussion

The correct answer is (B). An MRI showing a rotator cuff tear is considered diagnostic of a rotator cuff tear because of its high sensitivity, specificity, and accuracy. It has superb soft tissue imaging abilities (see Fig. 2–5). However, it should be noted that while MRI usually can differentiate between partial- and full-thickness rotator cuff tears, this varies with the power and accuracy of the MRI facility. This is also true with the ability of MRI to differentiate between partial-thickness rotator cuff tears and subacromial bursitis. An arthroscopy is needed for definitive differentiation of these pathologies.

 

 

 

Figure 2–5 Coronal oblique view MRI slice of a left shoulder. (Reproduced with permission from Smithius R and van de Woude HJ. Shoulder MR Anatomy: Normal Anatomy, Variants, and Checklist. Radiology Assistant. April 2, 2012.)

 

Shoulder CT scans (Answer A) are not typically used to diagnose rotator cuff tears. X-rays, aka roentgenograms (Answer C), can show signs of rotator cuff pathology but are not diagnostic. Some signs of chronic rotator cuff tears that are sometimes seen on AP view x-rays include calcific tendonitis, calcification of the coracohumeral ligament, proximal migration of the humerus, and cystic changes of the greater tuberosity. An outlet view x-ray can show a type III (hooked) acromion, which is correlated with a higher rate of rotator cuff tears, or an OS acromiale, which would require special consideration for surgical treatment. Shoulder arthrograms (Answer D) are used primarily only when MRI is contraindicated and are considered positive for a rotator cuff tear if dye leaks from the glenohumeral joint into the subacromial space. MR arthrogram (Answer E) has been shown to have equivalent diagnostic ability compared with standard MRI and can be used to diagnose rotator cuff tears. However, it adds an additional step and cost to a standard MRI, and it does not offer any additional diagnostic benefit for rotator cuff pathology. Therefore, standard MRI is preferred to MR arthrogram.

Shoulder ultrasound is another modality that can be used to diagnose rotator cuff tears. It is generally less expensive than MRI but the sensitivity and specificity are more operator-dependent.

 

Objectives: Did you learn...?

 

Clinically diagnose a rotator cuff tear?

 

Identify the most commonly torn rotator cuff muscle?

 

Perform the physical examination maneuvers to isolate and test each rotator cuff muscle?

 

Radiologically diagnose a rotator cuff tear?