Assessment and Management of the Painful Shoulder

Kurt P. Spindler, MD, Thomas T. Dovan, MD and Eric C. McCarty, MD Clinical Cornerstone 3(5):26-37, 2001

Abstract and Introduction

Abstract

The shoulder joint is a complex structure composed of intricate bony architecture and an ornate system of muscles, tendons, and ligaments. What many refer to as the "shoulder joint" is actually a combination of 4 articulations -- the glenohumeral joint, acromioclavicular joint, sternoclavicular joint, and the scapulothoracic articulation. These structures work together to provide the shoulder complex with multiple degrees of freedom, which allow the upper extremity to be abducted, adducted, rotated, flexed, and extended. Although this flexibility is vital for positioning the arm in space, it can make the evaluation of pathology difficult. Furthermore, neck pathology can refer pain to the shoulder, which may require a screening evaluation of the neck. This article reviews the relevant anatomy and discusses an approach to the differential diagnosis of shoulder pain.

Introduction

Several factors should be considered in evaluating the painful shoulder. The evaluation may not consist of a single diagnosis but rather multiple interrelated diagnoses, such as acromioclavicular pain and impingement. Some problems are clearly sport specific. For example, in the overhead athlete versus the contact athlete, more than one physical examination (PE) is required to detect changing pain patterns and the PE must be correlated with diagnostic studies. Natural history studies of injuries and treatment outcome studies are lacking. Only through a thorough clinical evaluation of the entire shoulder girdle coupled with a knowledge of relevant anatomy, medical history, clinical tests, and PE skills can a physician work through the algorithm for diagnosis and treatment of shoulder injury and pain.

Anatomy of the Shoulder

Glenohumeral Joint

The glenohumeral articulation has classically been described as a golf ball on a golf tee. Only ~30% of the humeral head articulates with the glenoid at any one time. Although this contact surface is greatly increased by the labrum, the glenohumeral joint is inherently unstable. The joint relies on static (ligaments and tendons) and dynamic (muscular contractions) stabilizers. The glenohumeral joint is responsible for the majority of motion in the coronal plane. For every 3ƒ of abduction, 2ƒ occur in the glenohumeral joint and 1ƒ at the scapulothoracic articulation.

Sternoclavicular Joint

The sternoclavicular joint is a diarthrodial joint whose articular surfaces are covered with fibrocartilage; it is a saddle-type joint, freely movable and functioning like a ball-and-socket joint. This joint is relatively incongruous and relies on multiple ligaments for stability. These ligaments include the intraarticular disk ligament, costoclavicular ligament, capsular ligament, and interclavicular ligament. Almost all motion of the upper extremity is transferred proximally to this joint. It can be dislocated from injury or can cause pain due to arthropathy.

Acromioclavicular Joint

The acromioclavicular joint is a diarthrodial joint whose articular surfaces are covered with hyaline cartilage, interposed with a fibrocartilaginous disk. Horizontal stability is provided by the capsular ligaments, mainly the superior acromioclavicular ligament. Vertical stability is provided by the coracoclavicular ligaments, the conoid and trapezoid ligaments.

Scapulothoracic Articulation

The scapulothoracic articulation consists of the scapula articulating with the bony thorax with a bursa interposed. Motion is controlled by a group of muscles that includes the rhomboideus major and minor, levator scapulae, serratus anterior, trapezius, omohyoid, and pectoralis minor. Disorders of these muscles can present as scapular winging or dyskinesia of the scapulothoracic articulation.

Rotator Cuff

The rotator cuff is composed of 4 muscles -- the supraspinatus, infraspinatus, teres minor, and subscapularis. The tendons of supraspinatus, infraspinatus, and teres minor insert into the greater tuberosity of the humerus; the subscapularis inserts into the lesser tuberosity. When a tear of the rotator cuff occurs, it is most commonly the supraspinatus that is torn. The infraspinatus and teres minor tendons can be affected if a large tear propagates posteriorly. Less frequently, these tendons can be torn independently.

Labrum, Ligaments, and Biceps Tendon

The glenohumeral joint is encased by a thin, lax, fibrous capsule. Anterior thickenings in the capsule -- referred to as the superior, middle, and inferior glenohumeral ligaments -- along with the glenoid labrum, are the main static stabilizers of the glenohumeral joint. The labrum functions to increase the surface area of the glenoid, enhances its stability, and is the fibrous attachment of the glenohumeral ligaments to the glenoid. The biceps tendon is anchored to the superior glenoid via the superior labrum and is commonly referred to as the biceps labral complex.

Coracoacromial Arch

The coracoacromial arch is formed by the acromion, the coracoacromial ligament, and the coracoid process. The main structure of the arch is the coracoacromial ligament, which is intimately involved in subacromial impingement syndrome.

Clinical Tests

Range of Motion

The first step is to document active range of motion of the neck, including flexion, extension, lateral bending, and rotation. Next, assess active and passive range of motion of the shoulder. If active range of motion is full, passive range of motion tests do not need to be performed. Ranges of motion that need to be documented are forward flexion (in the sagittal plane), abduction (in the coronal plane), and internal and external rotation. Internal rotation can be documented by vertebral level according to how high up the back the patient can place his or her thumb. External rotation should be documented at both 0ƒ and 90ƒ of abduction. Generally speaking, forward flexion and abduction are 0ƒ to 180ƒ, internal rotation is to ~T5 to T7, and the arm will externally rotate to 45ƒ.

Spurling's Test

With Spurling's test, the neck is positioned in lateral flexion and rotation with axial compression. Reproduction of radicular type pain to the ipsilateral side is a positive test. This position closes down the neural foramina, which compresses the cervical nerve roots as they exit the foramen. With a herniated nucleus pulposus or foraminal stenosis, this decrease in foraminal space is likely to reproduce radicular type pain.

Inspection and Palpation

Inspection of the shoulder requires adequate visualization of the entire upper extremity, shoulder girdle, chest, and back. Examination is performed with the shirt off for male patients, and a sleeveless shirt for female patients. The examiner should inspect muscle tone, symmetry, and deformity, especially at the acromioclavicular and sternoclavicular joints, shoulder, scapula, and clavicle. Scapular thoracic rhythm should be assessed from a posterior vantage point with the arms fully abducted.

After inspection, palpation of anatomic landmarks is critical to determine sites of tenderness. The examiner first palpates the neck, the acromioclavicular and sternoclavicular joints, followed by the posterior vertebral border of the scapula. Finally, attention is turned to the shoulder, where the coracoid, anterior, lateral, and posterior aspects of the shoulder are palpated for areas of pain.

Muscle Strength Testing

Muscle groups to concentrate on are the trapezius, serratus anterior, deltoid, and rotator cuff. The deltoid is tested in forward flexion for the anterior third, straight abduction for the middle third, and in extension for the posterior third. The serratus anterior is evaluated by having the patient push off a wall while standing. Winging of the scapula during this maneuver is classic when paralysis of the long thoracic nerve is involved. The supraspinatus can be tested by applying a downward force to the arms abducted 90ƒ, forward flexed 30ƒ, and internally rotated so that the thumbs are pointing down. The posterior cuff muscles (infraspinatus and teres minor) are evaluated by external rotation strength with the arm at the side and the elbow flexed to 90ƒ. The subscapularis is tested by internal rotation strength with the arm in the same position.

Lift-Off Test

To test the function of the subscapularis muscle, the patient internally rotates and extends the arm so that it lies on the patient's back -- about the level of the waist line. The patient then attempts to lift the arm posteriorly away from the back. If this is not possible, then the test is considered positive. A modification of this test is to have the examiner hold the patient's arm posteriorly away from the patient's back. When the examiner releases the arm and the patient is unable to actively maintain this position, the test is considered positive.

Impingement Sign and Impingement Test

Impingement sign, commonly referred to as impingement syndrome, is a mechanical impingement of the rotator cuff between the coracoacromial arch and the humeral head. Anything that decreases the volume of this space can cause impingement. Typically, calcifications in the acromioclavicular ligament and anterior acromial spur formation are the cause of impingement, which may or may not be associated with tears of the rotator cuff. Hypertrophy of the acromioclavicular joint secondary to arthritis has also been implicated in the cause of impingement. Arm positions that cause the humeral greater tuberosity to impinge against the inferior aspect of the acromion will reproduce pain in patients with impingement syndrome. Neer described the impingement sign as the reproduction of pain with passive elevation of the arm. The examiner uses one hand to stabilize the scapula, while the other hand raises the patient's arm in forced forward elevation with slight abduction. If pain is relieved after injection of 10 cc of 1% lidocaine into the subacromial space, then it is referred to as a positive impingement test.

Hawkins Impingement Test

The arm is elevated forward to 90ƒ with slight adduction. The examiner then internally rotates the arm, which brings the greater tuberosity, rotator cuff, and biceps tendon under the acromioclavicular arch. If pain is elicited with this maneuver then it is considered a positive test for impingement.

Stability Testing

Instability patterns of the shoulder include anterior, posterior, inferior, and a combination of the 3 referred to as multidirectional. The examination is used to assess possible directions of instability and to correlate these with apprehension and symptom reproduction. It is performed with the patient upright and supine, both positions with the scapula stabilized. For inferior instability, the arm is positioned along the side of the body and inferior traction is applied. A depression produced between the edge of the acromion and the humeral head is referred to as a sulcus sign. To assess passive anteroposterior translation, the load and shift test is performed. First an axial load is applied to the humerus, which seats the humeral head in the glenoid fossa if there is inherent subluxation. The examiner then applies posterior and anterior stresses to the humeral head and attempts to translate the head out of the glenoid fossa.

After translation patterns are evaluated, symptom reproduction and apprehension with provocative maneuvers are assessed. To evaluate anterior apprehension of the left shoulder, the examiner stands behind the patient placing the left hand on the patient's elbow. With the right hand, the thumb is positioned on the posterior humeral head to provide an anterior force while the fingers are placed anterior to help control any sudden instability. The arm is abducted to 90ƒ with the elbow flexed. With increasing external rotation and forward pressure on the humeral head, the patient may express an apprehensive look, try to resist with muscular contractions, or simply state that the shoulder is beginning to dislocate. This is a positive apprehension sign. These maneuvers are repeated with the patient supine and with the edge of the table stabilizing the scapula. Again the arm is abducted to 90ƒ and externally rotated while applying an anterior force. If apprehension or pain is encountered, then a posterior force is applied. If the apprehension and/or pain disappears, then it is a positive relocation test.

O'Brien's Test for Superior Labral Anteroposterior Lesions

With the patient standing, the arm is forward flexed to 90ƒ with the elbow straight. The patient adducts the arm 15ƒ to 20ƒ and fully internally rotates the shoulder so that the thumb is pointing down. The examiner then applies a downward force on the arm with the patient resisting. Next, the arm is externally rotated so that the thumb is pointing up. The examiner again applies a downward force to the arm while the patient resists. If pain is elicited with the thumb down and decreased or eliminated with the thumb up, then it is a positive test suggestive of a superior labral anteroposterior lesion.

Evaluation of Shoulder Pain

Common Principles of Musculoskeletal Examination

Several principles are common to all PEs and are summarized below. A proper site-specific history of the injured region is required. Key history facts for the injured or painful shoulder are listed in Table I. The physician should always examine the contralateral "normal" extremity. The accuracy of PE tests is dependent on patient relation. Diagnostic studies, including magnetic resonance imaging (MRI) and arthroscopy, are not substitutes for PE skills. The site of maximum point tenderness is important, especially to correlate a superficial site with the deeper anatomic structure.

Differential Diagnosis of Shoulder Pain

The evaluation is designed to test for the most common causes of shoulder pain in both athletes and nonathletes. Although individual tests as described are part of the PE, in scientific studies documenting sensitivity and specificity, no sequential algorithm has been prospectively evaluated for decision-making statistically, which requires more sophisticated statistical testing (partition-tree analysis). Therefore, the algorithm presented in this article is a clinical approach developed by the authors based on accuracy of individual tests and modified by clinical experience and the teaching of orthopedic and primary care residents and fellows for the past decade. The differential diagnosis for shoulder pain is shown in Table II.

Management of the Painful Shoulder

Algorithm

The key to management of the injured or painful shoulder in the athlete is correct diagnosis. Predominant sports-specific problems are outlined in Table III. The Figure demonstrates a stepwise approach for evaluating shoulder pain that begins at the neck, proceeds to the sternoclavicular, acromioclavicular, and scapulothoracic components of the shoulder joint, then focuses on particular anatomic sites, rotator cuff strength, and impingement signs, followed by glenohumeral tests. The physician should list all positive findings because multiple diagnoses are quite possible. A skilled examiner should take 7 to 8 minutes to accomplish this examination. The examiner should also review the relevant anatomy and conduct specific PE tests as necessary.

The major part of the PE is performed with the examiner facing the patient and dictating movement in a "Simon says" fashion. This seems to be the most reproducible way to get the patient to follow the movements desired. Except when the examiner is looking for muscle asymmetry and needs to approach the patient from the back to watch the movement of the scapula and shoulder, the examiner is facing the patient. A male patient should have his shirt off, and a female patient should be wearing a sleeveless shirt or tank top. The first part of the examination is to duplicate active neck motion, which includes flexion-extension (chin on chest, chin all the way up), lateral rotation (chin on left shoulder, chin on right shoulder), and lateral bending (ear on left shoulder, ear on right shoulder). Abnormal motions could be caused by trapezius spasm, nerve root irritation (either from a narrowed foramen or herniated disk), or degenerative changes. The parentheses in the Figure indicate the relevant diagnostic test. Positive findings should be recorded.

The examiner should then focus on active shoulder motion in forward flexion, abduction, external-internal rotation, and composite motions where the patient places an arm behind the back and then lifts the arm up and externally rotates it as if to throw a ball or to serve. If these motions are abnormal, passive range of motion of only the glenohumeral cavity is assessed. If passive range of motion is normal, the deficits could be pain, rotator cuff tear, or nerve deficit or injury. If the passive range of motion is abnormal, results could be indicative of pain (the patient will not adequately relax), a frozen shoulder (adhesive capsulitis) or degenerative changes that would be observed on x-ray. Finally, the examiner should perform a passive cross-arm adduction test, which pinches the subacromion space and is positive with impingement syndromes and also tests the acromioclavicular joint and is positive with acromioclavicular joint pain.

Proceed with palpation of anatomic sites. Begin with the sternoclavicular joint followed by the acromioclavicular joint and then the biceps tendon. In relatively thin individuals, the greater tuberosity can be palpated separately from the lateral edge of the acromion. The causes of pain in these sites are listed in the Figure.

Next, observe rotator cuff strength and evaluate the subscapularis, supraspinatus, infraspinatus, and teres minor muscles. Test the subscapularis initially in internal rotation, the infraspinatus and teres minor in external rotation with the arm at the side, then the supraspinatus with the arm in the empty-can position. If rotator cuff strength is abnormal, this could be caused by pain (which can be evaluated by a diagnostic lidocaine test), or it could be weak because of an observed tear (which can be diagnosed by MRI or arthroscopy). A finding can be abnormal secondary to neurologic injury as a result of a nerve root, peripheral nerve, burner, or plexus injury.

Impingement signs are then evaluated. Two preferred methods of the authors of this article are the Hawkins impingement test and the forced impingement test, which takes the elbow and gently forces the rotator cuff up against the lateral edge of the acromion. A positive test is indicative of pain, which suggests inflammation in the subacromion space. Determine whether this inflammation is tendinitis, bursitis, or a tear. Tendinitis or bursitis that is isolated would result in the remainder of the physical examination being normal or a proven lidocaine test. Tears should be assessed whether they are partial or complete and can be evaluated by MRI or arthroscopy. Partial tears can be clinically significant in a competitive overhead or functioning overhead athlete, whereas in a nonoverhead athlete these tears may be clinically silent. The athlete's activity should be factored into the decision for further diagnostic workup.

The final part of the examination evaluates glenohumeral instability and labral tears. This is the most difficult part of the examination and requires an extreme degree of skill on the part of the examiner as well as patient relaxation to determine if instability and/or labral tears exist. The patterns of instability that should be examined include anterior (with apprehension test), posterior (with a posterior drawer), and inferior (by applying a downward pressure on the arm). The position of instability by history as well as a PE and the component of multidirectional instability should be documented. Confirmatory tests include MRI, examination under anesthesia, and arthroscopy. Ability to detect labral signs indicative of a tear is probably the least accurate test for the shoulder. An O'Brien's test can be used as well as attempts at relaxation and circumduction of the arm overhead with a posterior force stressing the anterior superior labrum. If a patient has signs of a labral tear with clicking or popping or a positive O'Brien's test, the clinician should try to determine whether the findings are associated with instability, which would have profound implications on type of treatment and recovery time. In the authors' opinion, the PE and the MRI are not highly accurate for evaluating labral tears and arthroscopy is the most definitive procedure.

Some patients may not have any signs of labral tears, have no anatomic abnormal laxity patterns, but have "functional" instability, which can be manifested as secondary impingement or internal impingement. Internal impingement is most frequently observed in an overhead-throwing athlete. Secondary impingement is believed to occur from slightly increased laxity of the glenohumeral articulation, which allows riding up of the humeral head and pinching of the supraspinatus in the subacromion space and results in a positive impingement sign.

A small number of patients, particularly athletes, have an entirely normal PE, but continue to complain of pain. The examiner should look for training errors in the athlete's program or chronic overuse injury. Alternatively, pain may be a normal adaptation to increasing loads placed on the shoulder as it accommodates new demands. It should be stressed that repeated PEs over time, particularly with highly competitive athletes, are needed to evaluate changing pain patterns, which may highlight the real diagnostic culprit. For example, multiple diagnoses may be made after an athlete has a contact injury to the shoulder. The patient may have a positive palpation to trapezius, positive pain on the acromioclavicular joint in cross adduction, and an impingement sign. Repeat examination, after addressing these 3 areas in the next few days, may indicate the trapezius pain and spasm are resolved, acromioclavicular joint pain is resolved, but the impingement continues. At this point, the examiner can be more aggressive, if there is no indication of rotator cuff tear, and consider a corticosteroid injection. Conversely, the same patient could present a few days later with no trapezius pain or impingement pain but isolated acromioclavicular joint pain. Therefore, treatment would be directed at the acromioclavicular joint and may include a corticosteroid injection. The examiner must record the positive findings, using the algorithm, and review the clinical picture of problems with the shoulder, addressing each of them individually.

Importance of an Accurate Diagnosis

When a patient presents with a shoulder injury or pain, it is critical to any treatment that an accurate diagnosis be made. Once the evaluation skills are practiced and mastered, then both conservative and operative options can be addressed. In general, unless absolute indications for surgery are present (ie, rotator cuff tear in an athlete or recurrent instability with Bankart lesion), the physician can begin a conservative program with rehabilitation and activity modification. The physician should understand the role of selective lidocaine and corticosteroid injections to determine and treat subacromion pain syndromes and acromioclavicular joint pain. More detailed treatment scenarios are beyond the scope of this article and can be referenced when needed in major sports medicine texts.

Summary

Knowledge of the shoulder anatomy and the patient's pertinent history together with using a stepwise approach to examine shoulder pain, as in the algorithm presented, provides a basis for a complete evaluation of shoulder injury. Multiple diagnoses are common in the athlete with shoulder pain. This clinical approach is meant to serve as a building block, which each examiner can modify based on experience and confidence in individual tests for impingement, instability, and labral pathology. New imaging modalities or examinations also can be incorporated in the evaluation and diagnosis.

Side Bar

Key Point

The examiner should use a stepwise approach to physical examination of the athlete or patient presenting a complaint of shoulder injury, pain, weakness, or restriction of motion. The examination should proceed from the neck to the glenohumeral articulation.
Impingement syndrome is a mechanical impingement of the rotator cuff between the coracoacromial arch and the humeral head. Arm positions that cause the humeral greater tuberosity to impinge against the inferior aspect of the acromion will reproduce pain in patients with impingement syndrome.
Diagnostic studies such as MRI and arthroscopy are not substitutes for PE skills.
The key to management of the injured or painful shoulder is correct diagnosis.
Many injuries and diagnoses are specific to sports and relatively unique to an individual sport. Repeated PEs over time, particularly with highly competitive athletes, are necessary to evaluate changing pain patterns.

Table 1. Key History Facts

All Patients	Shoulder
Age Hand dominance Occupation Injury? Injury mechanism Length of time symptoms	Overhead use -- athletics/repetitive work Night pain Radicular symptoms Neck pain Any injections and location? Specifics rehabilitation? Surgery? (need operative dictation)

Table 2. Differential Diagnosisof Shoulderpain

Referred sources

Neck
Subdiaphragm
Ribs

Sternoclavicular
Acromioclavicular

Sprains (I-VI)
Fractures distal clavicle (I-III)
Instability -- horizontal
Degenerative
Osteolytes

Scapulothoracic bursitis
Glenohumeral

Rotator cuff
Tear (complete vs partial)
Tendinitis
Biceps tendinitis/tear
Impingement
Adhesive capsulitis -- frozen shoulder
Instability

Unidirectional -- anterior vs posterior
Multidirectional instability

Labral tears -- anterosuperior vs Bankart

Table 3. Predominant Sports-Specific Problems

Neurologic

Burners or stingers
Nerve root irritation
Brachial plexus injuries
Axillary nerve injuries
Suprascapular nerve entrapment

Acromioclavicular osteolysis
Rotator cuff

Tendinitis vs impingement
Primary (1) vs secondary (2) impingement
Internal impingement?

Glenohumeral instability

Subluxation dislocation
Unidirectional vs multidirectional

Labral pathology

Location-associated
Instability-associated