Essentials of Orthopedic Surgery, third edition / 08-The Shoulder

A lag sign can be documented when the patient has a loss of active motion with preservation of passive motion. The examiner positions the shoulder at the end range of full passive motion and instructs the patient to maintain the position. If the patient is unable to maintain the position and the extremity falls away, the patient is considered to have a positive lag sign. The hornblower’s sign is the lag sign for the abducted, externally rotated position and is suggestive of a massive rotator cuff tear involving the posterior cuff.

Strength Assessment

The relative strength of muscle groups can be assessed during the physical examination. To assess strength, the examiner manually resists the patient’s active motion in a defined plane such as abduction, adduction, or internal or external rotation. Asymmetrical weakness on the involved side can provide additional diagnostic information. Weakness or paralysis of the scapular stabilizer muscles can be assessed by having the patient perform pushups against a wall. Scapular winging can be elicited using this technique.

Neurologic Examination

In the absence of trauma or brachial plexopathies, most neurologic lesions about the shoulder involve a peripheral nerve. Common peripheral neuropathies in the shoulder girdle include the suprascapular, spinal accessory, and long thoracic nerves. Although these conditions can be painful, many patients report dysfunction or cosmetic deformity as the presenting complaint. These lesions are appreciated during the inspection, range of motion, and strength testing of the shoulder girdle. Suprascapular neuropathy can occur at the level of the suprascapular notch or proximal and involve both the supra and infraspinatus tendons, resulting in prominence of the scapular spine and weakness of forward elevation and external rotation. Suprascapular nerve lesions at the level of the spinoglenoid notch involve only the infraspinatus muscle, resulting in atrophy of the infraspinatus fossa and weakness of external rotation. Spinal accessory nerve injury is often iatrogenic from a posterior cervical node biopsy or a radical neck dissection for malignancy. Injury to the spinal accessory nerve (cranial nerve XI) results in trapezius dysfunction and lateral scapular winging. Long thoracic nerve injury is thought to be secondary to traction or contusion and affects the serratus anterior muscle, resulting in medial scapular winging. Medial or lateral refers to the direction toward which the inferior border of the scapula is directed. Nerve lesions in the shoulder girdle should be further evaluated with electromyography (EMG) and nerve conduction testing. The majority of these nerve lesions (except iatrogenic laceration) recover without surgical intervention.

ment sign is tested by passively internally rotating the humerus when the arm is at 90 degrees of forward flexion with the elbow flexed. A positive test is defined as shoulder pain with this maneuver. The drop-arm test is performed by placing the upper extremity at shoulder level (90 degrees) in the scapular plane with the thumb pointing downward. The test is considered positive when the patient is unable to maintain the extremity in this position and is indicative of superior rotator cuff pathology.

Two tests have been described to evaluate the subscapularis. The lift-off test is performed by having the patient place the hands behind the back with the arm internally rotated and the elbow flexed. The patient is then asked to lift the hands off the back without extending the elbows. If the patient is unable to perform the lift-off, the test is considered positive and indicative of subscapularis insufficiency. For patients who are unable to reach behind their back, the belly-press test can be used to evaluate the subscapularis. The belly-press test is performed by having the patient place the hands on the abdomen and, while pressing the hands to the abdomen, bringing the elbows anterior to the coronal plane of the body. Inability to perform the belly-press maneuver is a positive test.

Biceps Tendon (Long Head)

Speed’s test is used to evaluate the long head of the biceps tendon. The test is performed by having the patient maintain forward elevation of the upper extremity at shoulder height against resistance with the elbow extended and the forearm supinated. The test is considered positive when pain is produced in the area of the bicipital groove with this maneuver.

The active compression test, or O’Brien’s test, is used to evaluate the superior labral–biceps tendon complex. The test is performed in two steps. The upper extremity is brought to shoulder height in forward flexion with the forearm fully pronated (thumb down) and adducted approximately 15 degrees. The patient resists the examiner’s downward pressure from this position. If this maneuver elicits pain in the shoulder, the test is repeated with the forearm supinated. If the pain is reduced or absent with the second maneuver, the test is considered positive. A positive test indicates that the biceps tendon–superior labral complex is torn or detached from the superior glenoid.

Shoulder Instability

A number of tests have been described to evaluate shoulder instability. All the following tests can be performed with the patient is supine on the examining table. The apprehension test is performed with the shoulder abducted to 90 degrees and externally rotated to 90 degrees in the coronal plane of the body. From this position, the examiner continues to externally rotate the shoulder. If the patient experiences apprehension (fear of the shoulder dislocating), the test is considered positive. If the patient has a

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positive apprehension test, the examiner can reduce the subluxated humeral head by applying a posterior-directed force against the proximal humerus, thereby reducing the humeral head. If the apprehension is relieved, the relocation test is positive. The examiner can then release the proximal humerus. If apprehension recurs with release of the posterior-directed force, the release test is positive.

The load-and-shift test is used to assess the direction and degree of shoulder laxity. The examiner uses one hand to apply a longitudinal load to the humerus directed toward the glenohumeral joint. This hand is located at the elbow with the elbow flexed. The other hand is used to apply a perpendicular force to the proximal humeral shaft in an attempt to shift (subluxate or dislocate) the humeral head relative to the glenoid. The test is performed while maintaining the upper extremity in the coronal plane of the body. The degree of abduction/rotation and the direction of the applied force can be varied to evaluate the various glenohumeral ligaments. The test is graded by the examiner who determines through tactile sense whether the humeral head translates to the glenoid rim (1+); over the glenoid rim but spontaneously reduces (2+); or over the rim requiring manual reduction (3+).

Imaging Studies and Other Diagnostic Tests

The use of routine imaging studies and tests to evaluate the shoulder girdle for diagnostic purposes is not recommended. At the conclusion of the history and physical examination, the examiner should have a reasonable diagnosis. Additional tests or studies are used to answer specific questions. If the clinical diagnosis is frozen shoulder but the examiner is concerned that the patient has glenohumeral arthritis, it is reasonable to order radiographs to rule out osteoarthritis because the natural history and treatment of osteoarthritis and adhesive capsulitis are dissimilar. If the clinical diagnosis is rotator cuff impingement or tendonitis, there is no reason to obtain further studies initially as they will not change the recommended course of treatment.

Radiographs

The standard shoulder series includes an anteroposterior (AP) X-ray in the plane of the scapula, a Y-outlet view, and an axillary view. This series of X-rays is mandatory in the evaluation of shoulder girdle trauma. Unfortunately, the axillary view is often not obtained, yet it is the most sensitive for documenting shoulder dislocations. AP views with the humerus internally and externally rotated may be used to critically evaluate greater tuberosity fractures or calcific tendonitis. The scapula is approximately 45 degrees oblique to the coronal plane of the body; therefore, to obtain a true AP view of the glenohumeral joint, the X-ray beam must be obliquely oriented to the coronal plane of the body (Fig. 8-5). The AP view is useful

C D

FIGURE 8-5. These illustrations and X-rays demonstrated the importance of obtaining a “true” anteroposterior (AP) perspective of the glenohumeral joint. In the X-ray beam in (A), note that the AP view is actually one of the thorax, yielding an X-ray that shows overlap of the glenohumeral joint. When the beam is angled, however, as in (B), a “true” AP view of the glenohumeral joint is obtained. Note the differences in appearance in these views in (C) (AP view of the thorax) and

(D) (true AP view of the glenohumeral joint). (From Rockwood CA Jr, Matsen FA III (eds) The Shoulder, vol 1. Philadelphia: Saunders, 1990. Reprinted by permission.)

for evaluating the clavicle, AC joint, glenohumeral joint space, glenoid, scapular body, proximal humeral shaft, surgical neck, and greater tuberosity. The Y-outlet view is useful for evaluating the scapular spine, scapular body, coracoid, shape of the acromion, and spur formation in the CA ligament. The axillary view is critical in evaluating glenohumeral joint

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congruence. Anterior or posterior dislocations are best seen on the axillary view.

Magnetic Resonance Imaging

The magnetic resonance imaging (MRI) scan is commonly employed to evaluate the soft tissues of the shoulder girdle and is considered is the gold standard for evaluating the rotator cuff tendons. Subacromial fluid, tendon inflammation, and rotator cuff tears are all visible with MR imaging. MRI scans can be performed with an arthrogram (intraarticular contrast dye) to better delineate intraarticular structures such as labral tears and articular-sided partial rotator cuff tears. Standard MRI views of the shoulder include coronal oblique, sagittal oblique, and axial cuts. The coronal and sagittal views are termed oblique because they are obtained in the plane of the scapula that is oblique to the coronal and sagittal planes of the body. Although the MRI scan is a powerful tool in the evaluation of shoulder problems, it is a very sensitive test. Positive findings, therefore, may correlate poorly with a patient’s clinical presentation. For example, MRI scans have been obtained on patients with normal, painfree shoulders and documented that not only did a large number of these healthy patients have rotator cuff tears, but that the incidence of such asymptomatic tears increased with increasing age. It is therefore important to treat the patient and NOT the MRI scan.

Computerized Tomography

Computerized tomography (CT) scans are useful in the evaluation of bony abnormalities. In the setting of complex or comminuted shoulder girdle fractures, CT scanning with or without image reconstruction is a powerful tool for clinical decision making or preoperative planning. CT scans are also valuable in assessing bony deficiencies such as glenoid wear before reconstructive shoulder surgery. The CT scan has been demonstrated to be superior to the axillary radiograph in evaluating the glenoid before prosthetic arthroplasty.

Electrodiagnostic Testing

Electromyography (EMG) and nerve conduction velocity (NCV) testing are commonly used to evaluate neurologic lesions of the shoulder girdle. EMG testing involves placing small needle electrodes into the muscles to record resting potentials and firing patterns. NCV testing is used to document the speed with which an impulse is conducted along a peripheral nerve. Abnormalities such as a conduction block may indicate severe nerve injury. Electrodiagnostic testing is useful in documenting both the presence and recovery of peripheral nerve lesions.

Evaluation and Treatment of Common

Shoulder Problems

The majority of common shoulder girdle problems result from degenerative changes, overuse, or traumatic injury. Atraumatic shoulder pain is common and includes rotator cuff disease, arthropathy, adhesive capsulitis, calcific tendonitis, and multidirectional instability. Most atraumatic shoulder pain is initially treated with activity modification, antiinflammatory medication, and physical therapy. Treatment regimens may vary depending on the specific diagnosis. Calcific tendonitis, for example, responds well to subacromial corticosteroid injections. The physical therapy prescription may also vary depending on the diagnosis. Patients with adhesive capsulitis require stretching exercises, in contrast to patients with rotator cuff tendonitis who are treated with rotator cuff strengthening exercises. Surgical treatment in the atraumatic population is generally reserved for those patients who fail to respond to nonoperative treatment regimens. A basic algorithm for the evaluation of atraumatic shoulder pain is provided in Figure 8-6.

Traumatic injuries to the shoulder girdle are common and include both soft tissue and bony injury. Treatment is individualized based on the age of the patient, functional status of the patient, and the severity of the injury. Depending on the injury, nonoperative or operative treatment may be appropriate. Common traumatic injuries to the shoulder girdle include shoulder dislocations, AC joint injuries, clavicle fractures, and proximal humerus fractures, and these are reviewed in the skeletal trauma chapter. Contrary to popular belief, traumatic rotator cuff tears are relatively uncommon.

Rotator Cuff Disease

Degenerative and overuse injuries of the rotator cuff are common sources of shoulder pain and disability. Anterosuperior shoulder pain emanating from the rotator cuff (RC) under the coracoacromial arch has historically been called impingement syndrome. Impingement syndrome encompasses a spectrum of pathology in the subacromial region including subacromial bursitis, RC tendinopathy, partial-thickness RC tears, and full-thickness RC tears. Partialand full-thickness tears of the rotator cuff become more prevalent with increasing age. It is unusual for patients under the age of 40 years to present with RC tears in the absence of significant trauma. Conversely, older patients may present with massive RC tears after an innocuous event. There are two main theories that attempt to explain such degenerative cuff tears. The external impingement model suggests an extrinsic cause of RC tears such as abrasion of the anterosuperior cuff

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FIGURE 8-6. Algorithmic approach to the diagnosis and treatment of atraumatic shoulder pain.

under the acromion and coracoacromial arch. The intrinsic model suggests that a relatively poor blood supply to the critical zone of the rotator cuff in combination with high stresses across the cuff leads to RC tears. The true pathophysiology likely results from a combination of these models.

History

The chief complaint is usually anterosuperior shoulder pain, which often radiates to the lateral deltoid region. The pain is typically worse with overhead activities and at night. The patient may recall a minor traumatic event, or the pain may have started insidiously.

Examination

Inspection of the shoulder girdle usually reveals symmetry, but patients with degenerative cuff tears may present with atrophy of the supra or infraspinatus fossae. The patient typically has discrete tenderness at the cuff insertion on the greater tuberosity. The active range of motion is generally normal; however, some patients with RC tears may exhibit loss of active motion with preservation of passive motion. In this setting, the clinician may be able to document lag signs. Strength testing may reveal weakness of the supraspinatus or infraspinatus tendons. Special tests include the Neer and Hawkins’s impingement signs. If the patient has concomitant biceps tendon pathology, there may be tenderness at the bicipital groove, and Speed’s test may be positive. Tenderness over the AC joint may indicate that the AC joint is contributing to the painful condition. A cross-body adduction test recreating pain at the AC joint is considered confirmatory.

Differential Diagnosis

The differential diagnosis varies with the age of the patient. In older patients, the differential diagnosis includes arthritis, cervical spine pathology, metastatic disease, and visceral pathology such as cardiac disease. In younger patients, instability and labral pathology should be considered. In any age group, the differential diagnosis includes adhesive capsulitis, calcific tendonitis, and a variety of other less common shoulder problems (avascular necrosis, scapulothoracic dysfunction, and infection).

Radiographic Evaluation and Magnetic Resonance Imaging

The AP radiograph may reveal sclerosis and cyst formation of the greater tuberosity. The Y-outlet view shows the acromial morphology with potential narrowing of the subacromial space. In patients with long-standing RC tears, the distance between the humerus and acromion may be narrowed. The axillary view illustrates the joint space and may reveal an os acromiale. An MRI scan is useful for a number of reasons. Confirmation of RC disease (and exclusion of other etiologies) is reassuring, but not necessary.

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FIGURE 8-7. A tear of the supraspinatus tendon with fluid in the gap is easily appreciated in this coronal oblique magnetic resonance imaging (MRI) scan image of the glenohumeral joint.

The MRI scan is extremely useful for assessing the RC tendons and muscle bellies (Fig. 8-7). The presence, size, and chronicity of a RC tear directly impact patient care (surgical options), recovery, and, ultimately, prognosis.

Initial Treatment

The goal of treatment is to return the patient to painfree activity. Initially, treatment consists of education, rest, and activity modifications. If the pain is significant, an oral antiinflammatory medication can be prescribed. Once the painful period subsides, the patient may benefit from a course of physical therapy to strengthen the rotator cuff and scapular stabilizers. Radiographs are generally obtained in patients who fail initial therapy. A subacromial corticosteroid injection can be considered in a patient who fails to respond to the initial treatment over 2 to 3 months. Additional physical therapy can also be helpful. Patients who fail to respond to nonoperative management over 3 to 6 months may benefit from surgical treatment. Most surgeons will obtain an MRI scan before surgical treatment.