Evaluation of the patient with shoulder complaints
Bruce C Anderson, MD
Ronald J Anderson, MD
INTRODUCTION ? Shoulder pain is a common musculoskeletal complaint that may be due either to intrinsic disorders of the shoulder or referred pain. The former include injuries and acute or chronic inflammation of the shoulder joint, tendons, surrounding ligaments, or periarticular structures [1]. This review will provide a general approach to the evaluation of patients with shoulder pain. More in-depth discussions of the diagnosis and treatment of specific disorders of the shoulder are found separately.
ANATOMY ? The shoulder girdle is composed of three bones (the clavicle, scapula, and proximal humerus) and four articular surfaces (sternoclavicular, acromioclavicular, glenohumeral, and scapulothoracic). The shoulder joint is defined by a thin capsule that is bounded by surrounding muscles and ligaments (show figure 1). The shoulder is loosely constrained within the joint capsule and has a greater range of motion than any other joint in the body. The glenohumeral joint is the principal articulation, but only 25 percent of the humeral head surface makes contact with the glenoid.
The rotator cuff stabilizes the joint. It is composed of four tendons -- supraspinatus, infraspinatus, subscapularis, and teres minor -- which form a cuff around the head of the humerus. These tendons are attached to the humerus by their respective tendons.
The rotator cuff rotates the shoulder and abducts the arm beyond the initial 20 degrees (initial abduction is performed by the deltoid muscle). Shoulder motion is also dependent upon the acromioclavicular, sternoclavicular, and costochondral joints.
The subacromial bursa, also referred to as the subdeltoid bursa, lies between the acromion process and the humeral head (show figure 1). Its sole, vital function is to lubricate and protect the rotator cuff tendons from the pressure and friction of the under side of the acromion. These bursae connect with the glenohumeral (true shoulder) joint in about one-half the population.
ETIOLOGY ? Approximately 85 percent of patients who present with shoulder pain have a disorder intrinsic to the shoulder. The remainder have referred pain, most often from the neck, but occasionally from other medical problems. Acute symptoms (less than two weeks duration) in patients with a history of recent trauma are typically due to a dislocation, fracture, or rotator cuff tear [2]. In addition to pain, patients may complain that the shoulder is discolored, deformed, and swollen.
The causes of shoulder pain vary with age (show table 1):
Sports injuries due to overuse ("muscular strain") and subluxation of the glenohumeral joint are most common in adolescents and young adults [2]. "Shoulder separation," due to subluxation or dislocation of the acromioclavicular joint, is seen following direct trauma on the point of the shoulder.
Middle-aged and older individuals develop shoulder pain due to rotator cuff lesions, such as supraspinatus tendonitis and partial or full thickness tears. Frozen shoulder syndrome and symptomatic osteoarthritis also occur at this age. Bilateral shoulder involvement suggests an inflammatory process such as polymyalgia rheumatica or rheumatoid arthritis, or rarely hypothyroidism.
Less than 1 percent of shoulder injuries in people under the age of 30 are complete rotator cuff tears; in contrast, up to 35 percent of patients older than age 45 who complain of shoulder pain have a complete rotator cuff tear [3].
Rotator cuff injury ? The rotator cuff tendons are uniquely susceptible to the compressive forces of subacromial impingement and dominate the conditions affecting the shoulder, especially in patients over the age of 30 [4]. Improper use, poor muscular conditioning, and failure of the subacromial bursa to adequately protect the supporting tendons may result in acute inflammation, calcification, degenerative thinning, and tendon tear.
Impingement syndrome ? Impingement syndrome is the term used to describe symptoms that result from compression of the rotator cuff tendons and the subacromial bursa between the greater tubercle of the humeral head and the lateral edge of the acromion process [5]. The subacromial bursa, located just under the inferior surface of the acromion, functions to protect the tendons from the compressive forces of the two bones. However, repetitive overhead reaching, pushing, pulling, and lifting with the arms outstretched leads to compression ("subacromial impingement") and irritation of the tendons. Impingement is the principle cause of rotator cuff tendonitis. (See "Shoulder impingement syndrome"). Neer described three stages of shoulder impingement that he estimated lead to 95 percent of rotator cuff tears [6]:
Stage 1 ? Edema and hemorrhage
Stage 2 ? Cuff fibrosis, thickening, and partial cuff tearing
Stage 3 ? Full thickness tendon tears, bony changes, and tendon rupture
The symptoms of impingement syndrome are nearly identical to those of rotator cuff tendonitis (see below). Overhead reaching and positioning cause pain over the outer deltoid. Atrophy of the muscles around the top and back of the shoulder may be apparent if symptoms are longstanding. Crepitus may be felt with attempts to lift the arm beyond 60º. Patients with rounded shoulders (a down-sloping acromial angle), poor muscular development, and occupations that require work at or above the shoulder are at greatest risk.
Tendonitis ? Rotator cuff tendonitis is an inflammation of the supraspinatus (abduction) and infraspinatus (external rotation) tendons. Patients complain of shoulder pain aggravated by reaching, pushing, pulling, lifting, positioning the arm above the shoulder level, or lying on the side. Most patients do not describe an injury or fall. The patient typically places the hand over the outer deltoid, rubbing the muscle in an up-and-down direction when describing the pain. Common shoulder tendonitis must be distinguished from frozen shoulder (loss of range of motion), rotator cuff tendon tear (persistent weakness), and biceps tendonitis (painful arm flexion). (See "Rotator cuff tendonitis").
Tendon tear ? Rotator cuff tendon tears, loss of the normal integrity of the infraspinatus tendon, the supraspinatus tendon, or both, occur as the end result of chronic subacromial impingement, progressive tendon degeneration, traumatic injury, or a combination of these factors. Tears occur primarily in the supraspinatus tendon. (See "Rotator cuff tear").
Patients complain of shoulder weakness, localized pain over the upper back, and a popping or catching sensation when the shoulder is moved; night pain is characteristic and often affects sleep. Injuries most commonly associated with acute rotator cuff tendon tears include falls onto the outstretched arm, falls directly onto the outer shoulder, vigorous pulling on a lawn mower cable, and unusual heavy pushing and pulling.
Shoulder function will be preserved if the tear parallels the direction of the tendon fibers or is small in size, and the patient will complain only of shoulder pain, pain with direct pressure, and pain aggravated by active reaching, lifting, pushing and pulling. However, if the tear is large, affecting both the supraspinatus and infraspinatus tendons, and is transverse in direction (total interruption of the tendon with muscle retraction), the patient will complain of weakness, the typical symptoms of tendonitis, and dramatic loss of function -- an inability to reach overhead, lift with an outstretched arm, and an impairment of pushing and pulling.
Acromioclavicular injury ? The second most common problem in patients with shoulder complaints occurs at the acromioclavicular (AC) joint. The joint is susceptible to arthritic change (a nearly universal condition, although most patients do not become symptomatic) and trauma ("shoulder separation"). (See "Acromioclavicular injury").
Patients complain of anterior shoulder pain, deformity, or both and often point to the AC joint when describing their symptoms. Patients with an acute separation usually relate a history of falling directly on the shoulder. Those with second and third degree sprains from injury often hold their arm close to the chest and resist rotation and elevation. Patients with osteoarthritis may describe a grinding or popping sensation when reaching overhead or across the chest.
Frozen shoulder ? Frozen shoulder is a descriptive term that refers to a stiffened glenohumeral joint that has lost significant range of motion (abduction and rotation). It is a reversible contraction of the joint capsule in almost all cases. (See "Frozen shoulder").
The most common cause of a frozen shoulder is rotator cuff tendonitis; approximately 10 percent of patients with this disorder will develop a frozen shoulder. Patients with diabetes, low pain thresholds, and poor compliance to exercise therapy are at greatest risk [7,8]. Use of a sling also can contribute to the development of frozen shoulder.
The symptoms and signs of frozen shoulder and rotator cuff tendonitis overlap. Patients with frozen shoulder primarily complain of stiffness. The loss of range of motion causes various degrees of impaired function, including limited reaching (overhead, across the chest, and so forth) and limited rotation (unable to scratch the back, putting on a coat, and so forth). In contrast, patients with rotator cuff tendonitis suffer similar restrictions, but their limitations are more due to pain rather than an absolute loss of movement.
Biceps tendonitis/rupture ? Biceps tendonitis is an inflammation of the long head of the biceps tendon as it passes through the bicipital groove of the anterior humerus. Repetitive lifting, and to a lesser extent overhead reaching, leads to inflammation, microtearing and, if untreated, degenerative change. Unusual or vigorous lifting in the setting of a chronically inflamed tendon can lead to the spontaneous rupture. (See "Biceps tendonitis and rupture").
The patient complains of anterior shoulder pain aggravated by lifting, overhead reaching, or both, often taking one finger and pointing directly to the bicipital groove when describing the area of discomfort. A dramatic change in symptoms and description of a lump just above the antecubital fossa suggests an acute long head tendon rupture. Weakness is most often attributed to the pain of active tendonitis. Rupture of the long head of the biceps rarely is associated with significant weakness; the brachioradialis and the short head of the biceps account for 80 to 85 percent of the strength of elbow flexion.
Subcapsular bursitis ? Subcapsular bursitis results from the mechanical pressure and friction between the superior-medial angle of the scapula and the adjacent 2nd and 3rd ribs. Poor muscular development in thin patients, dorsokyphotic posture, repetitive to-and-fro motion of the scapula (ironing, assembly work, etc.) and direct pressure are common causes.
Patients complain of localized pain over the upper back or a popping sound whenever the shoulder is shrugged. A typical patient has poor muscular development, an asthenic physique, and poor posture.
Glenohumeral osteoarthritis ? Osteoarthritis of the glenohumeral joint represents wear-and-tear of the articular cartilage of the glenoid labrum and humeral head. It is an uncommon problem that is in most cases preceded by trauma, although the injury may have occurred years earlier. Injuries that are associated with the development of osteoarthritis include previous dislocation, humeral head or neck fracture, large rotator cuff tendon tears (loss of musculotendinous support), and rheumatoid arthritis. Patients complain of the gradual development of anterior shoulder pain and stiffness over a period of months to years. (See "Glenohumeral osteoarthritis").
Multidirectional shoulder instability ? Multidirectional instability of the shoulder is synonymous with "subluxation," "loose" shoulder, or partial dislocation. It is more common in young woman with poor muscular development, patients with large rotator cuff tendon tears (loss of muscular support), and in athletes under the age of 40, especially swimmers and throwers. The symptoms are vague and nonspecific (looseness or crepitation) unless the condition is complicated by rotator cuff tendonitis. (See "Multidirectional instability of the shoulder").
Referred pain ? Referred pain to the shoulder may be seen in a variety of clinical settings:
Neural impingement at the level of the cervical spine due to disc herniation or spinal stenosis. (See "Evaluation of the patient with neck pain").
Peripheral nerve entrapment distal to the spinal column, with involvement of either the long thoracic or suprascapular nerves. (See "Nerve entrapment syndromes of the shoulder").
Diaphragmatic irritation, intrathoracic tumors, and distension of the hepatic capsule can produce ipsilateral shoulder pain. (See "Cancer pain syndromes" and see "Pancoast's syndrome and superior (pulmonary) sulcus tumors").
Myocardial ischemia with associated left shoulder pain.
A distinguishing characteristic of referred pain, in contrast to intrinsic shoulder problems, is that shoulder movement is normal and does not alter the character of the pain. A careful history can distinguish among the causes of referred shoulder pain.
PAIN PATTERNS ? Patients who are experiencing a problem unique or intrinsic to the shoulder present either with complaints of shoulder pain provoked by specific movement(s), stiffness or lack of flexibility, weakness or loss of function, or a combination of these symptoms.
Lateral deltoid pain ? Lateral deltoid pain that is aggravated by reaching is the most common pain pattern. It is the classic pattern of pain associated with impingement syndrome and the various stages of rotator cuff tendonitis (simple strain, uncomplicated tendonitis, chronic calcific tendonitis, tendonitis complicated by tear). Frozen shoulder is the most likely diagnosis when this pain pattern is accompanied by stiffness and a measurable loss of movement in external rotation or abduction. Rotator cuff tendonitis complicated by tear is suspected when this pain pattern is complicated by weakness and a measurable loss of strength in external rotation or abduction (a loss that is not attributed to poor effort).
Anterior shoulder pain ? Anterior shoulder pain is much less common than lateral deltoid pain and is characteristic of the conditions affecting the AC joint, glenohumeral joint, or the anterior tendons (long head of the biceps, subscapularis, and rarely the pectoralis major tendons). AC separation or osteoarthritis is suspected when the pain is well localized (the patient often uses one finger to point to the end of the clavicle). Involvement of the glenohumeral joint is suspected when anterior shoulder pain is aggravated by movement in many directions. Tendonitis is suspected when the pain is aggravated by the following selective movements:
Lifting ? Long head of the biceps
Reaching ? Rotator cuff tendonitis
Pushing ? Pectoralis major
Posterior shoulder pain ? Posterior shoulder pain is the least common pain pattern of the intrinsic conditions affecting the shoulder. Although rotator cuff tendonitis can refer pain over the broad area of the scapula, most of the pain in this area is referred from the cervical spine (cervical strain or radiculopathy).
Poorly localized pain ? All of the aforementioned pain patterns are usually well localized. Pain that is poorly localized or vaguely described is either referred from the neck, compression neuropathy, arises from the bone, or is a reflection of the psychological overtones of cases under litigation or with malingering.
Clinical pearls
Common shoulder tendonitis is the most common diagnosis at the shoulder (70 percent of all diagnoses).
Patients that complain of shoulder pain aggravated by reaching and direct pressure have a 75 to 80 percent chance of having either impingement or impingement complicated by rotator cuff tendonitis.
Common shoulder tendonitis most often affects the supraspinatus tendon (pain reproduced by isometric testing of midarc abduction, see below). It has the greatest susceptibility to impingement since it lies directly under the acromion and above the greater tubercle.
"Uncomplicated" rotator cuff tendonitis refers to an inflamed tendon(s) that is not complicated by frozen shoulder (10 percent), AC joint osteoarthritis, rotator cuff tendon tear (1 to 2 percent), or glenohumeral arthritis (<1 percent).
EXAMINATION ? Efficient examination of the shoulder combines functional testing of the glenohumeral joint with a focused evaluation of the surrounding tendons and auxiliary joints (show table 2A-2B).
Range of motion testing in abduction and external rotation (passively performed), estimation of the strength of the infraspinatus muscle, and assessment of the overall tightness of the subacromial space are performed to determine the general function of the shoulder and exclude significant involvement of the ball-and-socket joint.
The "painful arc maneuver" (passively abducting the glenohumeral joint while simultaneously preventing shoulder shrugging) is performed to assess the degree of subacromial impingement.
If impingement is present, subacromial tenderness or bicipital groove tenderness is combined with isometric testing of each individual tendon to determine the number of inflamed tendons.
Involvement of the acromioclavicular or sternoclavicular joints, or the subscapular bursa is determined by direct palpation.
These issues are discussed further below. The sensitivity and specificity of the various diagnostic maneuvers are given when well performed studies are available, but the data are limited. Studies have found relatively poor interobserver agreement in the interpretation of clinical examinations of the shoulder, even by highly experienced physician and non physician examiners [9,10].
Preliminary maneuvers ? Preliminary examination maneuvers are used to:
Define the origin of the shoulder pain (eg, intrinsic to the shoulder or referred pain)
Determine whether there is involvement of the glenohumeral joint
Determine the severity of the condition
Range of motion ? The "NFL" touchdown sign is an active maneuver used to assess range of motion of the shoulder joint and the strength of abduction (show picture 1). Full abduction requires a normal glenohumeral joint, intact rotator cuff tendons, a functional AC joint, and reasonably well developed deltoid and rotator cuff muscles. The following findings may be noted during range of motion testing:
Severe pain is associated with acute rotator cuff tendonitis and inflammatory or septic arthritis.
True weakness is association with rotator cuff tendon tear.
Patients with a frozen shoulder will have stiffness, while glenohumeral osteoarthritis is associated with stiffness and pain.
Patients who have had trauma resulting in dislocation, AC joint separation, or fracture will not even attempt the maneuver.
The drop arm test refers to the ability of the patient to smoothly lower the arms after they are raised. In a study of 100 patients with shoulder impingement, a positive drop arm test (eg, the affected arm is less well controlled than the unaffected arm when lowering to the sides) was highly specific for the diagnosis of rotator cuff tear, suggesting that a positive test is virtually diagnostic [11]. However, a negative test does not rule out the disorder, as the sensitivity was only 21 percent.
Joint rotation ? The Apley scratch sign is used to assess rotation of the shoulder joint (show picture 2). Full rotation requires a normal glenohumeral joint, intact rotator cuff tendons, and reasonably well developed rotator cuff muscles. Thus, rotation is limited with:
Frozen shoulder
Arthritis of the glenohumeral joint (osteoarthritis or inflammatory arthritis)
Acute inflammation of rotator cuff tendonitis
The impairment of rotation correlates well with the severity of these conditions. Side-to-side comparison of the placement of the thumb along the spinous processes of the vertebral column provides the most practical and objective measurement of rotation. This maneuver is used to objectively follow the response to treatment and as a guide to the appropriateness of surgical referral.
Overall shoulder strength ? The weighted "NFL" touchdown sign is used to evaluate the overall strength of the shoulder and, in particular, the strength of the rotator cuff and deltoid muscles (show picture 3). Full abduction requires a normal glenohumeral joint, intact rotator cuff tendons, a functional AC joint, and well developed deltoid and rotator cuff muscles. The following findings may be noted:
An inability to lift the unweighted arm is consistent with complete rotator cuff tear, severe atrophy of the rotator cuff and deltoid muscles, severe C5 radiculopathy, or supracapsular nerve palsy.
Patients who can lift a one- or two- but not five-pound weight may have a partial rotator cuff tear, poorly developed muscles, or partial C5 radiculopathy.
The ability to lift a five pound weight or greater is consistent with an intact rotator cuff tendon.
Strength of external rotation ? The infraspinatus muscle is responsible for external rotation with the teres minor muscle contributing to a minor degree. Isometric testing of external rotation with resistance bands is used to evaluate the specific strength of external shoulder rotation (show picture 4). The following findings may be noted:
Bilateral weakness is consistent with poor muscular development, bilateral rotator cuff tears, bilateral glenohumeral arthritis, or any other chronic condition.
Unilateral weakness suggests the diagnosis of rotator cuff tendon tear, C5 radiculopathy, or supracapsular nerve palsy.
Looseness of the shoulder ? The deltoid muscle arises from the acromion and attaches to the mid humerus. The supraspinatus tendon attaches to the greater tubercle. Thus, downward movement of the humeral head is influenced by the tone and bulk of the deltoid, the tone and thickness of the supraspinatus tendon, and the redundancy of the glenohumeral capsule.
The sulcus sign maneuver evaluates the looseness of the shoulder (especially, the subacromial space) and is used to assess the patient's tolerance of the Codman pendulum stretch exercise (show picture 5). The following findings may be noted:
No movement can be seen in patients with extreme guarding or tension, fibromyalgia, or an overly developed deltoid muscle.
One-quarter inch of movement is normal.
One-half inch or greater movement is consistent with hypermobility (subluxation).
Specific diagnostic maneuvers ? The following maneuvers are used to rapidly identify the anatomical structure responsible for the patient's shoulder pain. Emphasis is placed upon:
Evaluation of impingement
Assessment of conditions affecting the rotator cuff and bicipital tendons
Examination for the most common conditions affecting the three auxiliary joints of the shoulder (the AC Joint, SC Joint, and subscapular bursa).
Subacromial space tenderness ? The acromial process of the scapula is covered by the deltoid muscle. The supraspinatus tendon attaches to the greater tubercle, located just under the anterior third of the acromion. Palpation of the subacromial space may lead to the following findings (show picture 6):
Focal tenderness is consistent with a diagnosis of impingement syndrome, rotator cuff tendonitis, rotator cuff tear, or a humeral bony lesion.
Diffuse tenderness may be seen with subacromial bursitis or in patients with a low pain threshold.
Degree of impingement ? The rotator cuff tendons and subacromial bursa are located in the subacromial space between the acromial process of the scapula and the top of the humeral head. In patients with subacromial tenderness, the passive painful arc maneuver is used to assess the degree of impingement (show picture 7). Note whether the patient guards by shrugging as the maneuver is performed:
Pain at 90 degrees is consistent with mild impingement
Pain at 60 to 70 degrees is consistent with moderate impingement
Pain at 45 degrees or below is consistent with severe impingement
The value of the painful arc maneuver for diagnosing subacromial impingement was evaluated in a study of 125 patients with painful shoulders [12]. The specificity was relatively high (81 percent), suggesting that a positive test is highly suggestive of the presence of impingement. However, the sensitivity was low (33 percent), suggesting that a negative test does not rule out the disorder.
Assessment of the supraspinatus tendon ? Of the three abductors of the shoulder, the deltoid, supraspinatus, and the trapezius muscles, the supraspinatus, located in the supraspinatus fossa and attaching to the top of the greater tubercle of the humeral head, is responsible for abduction in the mid arc. Thus, isometric testing of the supraspinatus tendon in midarc assesses the strength, integrity, and degree of inflammation of the supraspinatus tendon (show picture 8):
Pain and normal strength are seen in patients with rotator cuff tendonitis (affecting the supraspinatus).
Pain and weakness are seen in patients with rotator cuff tendonitis or rotator cuff tendon tear.
Weakness alone may be seen in patients with rotator cuff tear, muscular atrophy, C5 radiculopathy, or suprascapular nerve palsy.
In one study of 55 patients with impingement, the sensitivity of this test for the diagnosis of supraspinatus tendon tear was high, but the specificity was low [13]. The severity of functional impairment during testing did not correlate well with the size of the tear.
Assessment of the infraspinatus tendon ? The infraspinatus is the principle external rotator of the shoulder (the teres minor plays a minor role). Isometric testing of the infraspinatus tendon in neutral position is used to assess the strength, integrity, and degree of inflammation of the infraspinatus tendon (show picture 9):
Pain and normal strength are consistent with rotator cuff tendonitis.
Pain and weakness are consistent with rotator cuff tendonitis or rotator cuff tendon tear.
Weakness alone is consistent with rotator cuff tear, muscular atrophy, C5 radiculopathy, or suprascapular nerve palsy.
Joint tenderness ? Tenderness of the AC joint, SC joint, and subcapsular bursa are assessed as follows. The anterior, lateral, and posterior edges of the acromion are marked with a pen. The AC joint is palpated at the juncture of the acromion and distal clavicle, approximately one and one-half inches proximally from the lateral edge of the acromion (show picture 10). The SC joint is palpated at the juncture of the proximal end of the clavicle and the lateral edge of the sternum, approximately one inch from the midline of the body. The subcapsular bursa is palpated at the junction of the superior-medial angle of the scapula and the closest underlying rib (exposure of this bursa requires full adduction of the ipsilateral arm by asking the patient to hold his opposite shoulder (show picture 11).
Clinical pearls ? The following general considerations apply to the evaluation of patients with shoulder complaints.
Impingement is a universal problem. It is determined by the painful arc maneuver and subacromial tenderness.
Subtle impingement can be brought out by internally rotating the shoulder, bringing the greater tubercle into greater contact with the under surface of the acromion (thumb down).
The patient's susceptibility to impingement is determined by the acromial angle. The greater the acromial angle the greater the chance of impingement and the greater chance of chronic tendonitis and possible acromioplasty.
The severity of impingement and rotator cuff tendonitis is determined by the angle at which the arc becomes painful (the lower the angle the greater the severity).
A painful response to isometric resistance of midarc abduction and external rotation defines active rotator cuff tendonitis and differentiates it from impingement syndrome. Impingement is the mechanical component of rotator cuff tendonitis and in its purest form is not associated with inflammation, while rotator cuff tendonitis with impingement has both a mechanical and inflammatory component.
Because the glenohumeral joint lies deep within the soft tissues, small or moderate sized effusions are usually not detectable on physical examination. Warmth or redness may not be observed even with acute inflammation. Thus, radiographic imaging by ultrasonography may be required to establish the presence of an effusion. However, the definitive test is demonstrating excessive synovial fluid by aspiration of the joint.
CONFIRMATORY TESTS ? When the above examination suggests the presence of a specific disorder, certain tests can be performed to confirm the diagnosis.
Lidocaine injection test ? The lidocaine injection test is used to (show picture 12):
Exclude glenohumeral joint involvement
Confirm rotator cuff tendonitis
Exclude rotator cuff tear
Determine the degree of frozen shoulder
Patients with a rotator cuff tear will have persistent weakness despite pain relief with injection, while those with rotator cuff tendonitis will have normal strength in association with pain relief. Patients with a frozen shoulder will have persistent loss of range of motion. Dramatic reduction in pain and improvement in overall shoulder function after injection of the subacromial bursa effectively rules out a significant glenohumeral joint process.
The lidocaine injection test in the subacromial bursa is indicated when the history and physical examination cannot effectively exclude an underlying rotator cuff tendon tear, a developing frozen shoulder, or concurrent involvement of the AC joint.
Local anesthetic block at the bicipital groove ? Bicipital tendonitis can be confirmed by local anesthetic block (show picture 13). This is most often indicated in the patient presenting with anterior shoulder pain with an equivocal physical examination demonstrating signs of bicipital tendonitis and rotator cuff tendonitis, especially involving the subscapularis tendon (an internal rotator and adductor of the shoulder).
Radiographic studies ? Diagnostic imaging of the shoulder may be valuable when directed by the history and physical examination. A variety of modalites may be employed. (See "Radiologic evaluation of the painful shoulder").
Plain radiographs ? Plain radiographs of the shoulder generally have limited benefit in the evaluation of shoulder pain. This was illustrated in a study of 312 patients seen in an emergency room setting for shoulder pain: only 37 of the 185 shoulder films (20 percent) were therapeutically informative, ie, identified conditions requiring specific therapy such as a fracture or dislocation [14]. No patient without a shoulder deformity or a precipitating fall had an informative radiograph.
A subsequent study of 206 patients used the presence or absence of the following features: history of falling, swelling, rest pain, abnormalities in range of motion (ROM), and obvious deformities of the shoulder, to help identify those in whom a shoulder radiograph was unlikely to be informative [15]. Among those without obvious shoulder deformities and swelling, the following three groups had relatively insignificant radiographs:
Patients without rest pain who had fallen. No significant radiographic findings were found among 18 patients with these features.
Patients who had fallen, had rest pain, and had normal ROM. No therapeutically informative radiographs were reported in 10 such patients.
Patients who had not fallen. Only 1 of 107 such patients had a lytic lesion discovered on radiograph; this individual was already known to have multiple myeloma.
While there are no specific guidelines for when radiography is indicated, we generally recommend obtaining plain films in patients who have lost range of motion, particularly when there is severe pain and after trauma. Plain films can identify the following:
Glenohumeral osteoarthritis (show radiograph 1)
AC joint arthritis or injury (show radiograph 2)
SC joint arthritis (apical lordotic views of the chest)
In addition, indirect evidence of rotator cuff thinning, tear, or both may be evident on plain x-ray of the shoulder (show radiograph 3). A subacromial space measurement less than 1 cm suggests thinning with or without tear, which can be confirmed by MRI.
When plain films are obtained in a patient with a history of trauma, both AP and axillary views are warranted since some conditions can be missed on the former alone.
Magnetic resonance imaging ? MRI is the preferred imaging study for patients with suspected impingement and rotator cuff injury. A normal MRI suggests that the likelihood of a rotator cuff tear is less than 10 percent [16-18]. On the other hand, MRI findings for rotator cuff tears are not highly specific, particularly in older patients. This was illustrated in a study that found up to one-third of asymptomatic patients overall had rotator cuff tears on MRI, as did more than one-half of asymptomatic patients over the age of 60 [19]. The sensitivity and specificity of MRI for the diagnosis of impingement are approximately 93 and 87 percent, respectively [20].
MRI is also useful in the evaluation of avascular necrosis, biceps tendonitis and rupture, inflammatory processes, and tumors [21].
Arthrography ? Arthrography has largely been replaced by MRI for the diagnosis of rotator cuff disorders. It is specific for rotator cuff tears, but has a low sensitivity since it cannot detect particle thickness tears nor associated soft tissue injuries [22]. Arthrography still may be useful for evaluating frozen shoulder and may even be therapeutic. (See "Frozen shoulder").
SUMMARY ? A careful history and physical examination, supplemented occasionally by radiographic studies, can determine the cause of shoulder pain in the majority of patients. Subacromial impingement, ultimately leading to rotator cuff tendonitis and/or tear, are the most common conditions affecting the shoulder, especially in patients over the age of 30 (show table 1).
The preliminary maneuvers described above are used to define the origin of the shoulder pain (eg, intrinsic to the shoulder or referred pain), determine whether there is involvement of the glenohumeral joint, and determine the severity of the condition; these should be performed in all patients complaining of shoulder pain (show picture 1, show picture 2, show picture 3, show picture 4, show picture 5).
If these tests suggest a process intrinsic to the shoulder, in most cases the emphasis is on evaluating for impingement and rotator cuff tendonitis or tear. One study prospectively assessed the diagnostic utility of various aspects of the physical examination in 400 patients with shoulder pain [23]. The combination of supraspinatus weakness (show picture 8), weakness in external rotation (show picture 4), and impingement (show picture 7) was associated with a 98 percent likelihood of having a rotator cuff tear. Patients over 60 years of age with two of these three physical findings had approximately the same probability of a cuff tear. On the other hand, absence of these features excluded the diagnosis (less than 5 percent chance). Patients with one positive finding, or two positive findings if under the age of 60, needed an imaging study to clarify the diagnosis. A similar study found that weakness with external rotation, age 65, and night pain best predicted the presence of rotator cuff tear [24].
There are no specific guidelines for when radiography is indicated in the evaluation of shoulder pain. We generally recommend obtaining plain films in patients who have lost range of motion, particularly when there is severe pain and after trauma. When plain films are obtained in a patient with a history of trauma, both AP and axillary views are warranted since some conditions can be missed on the former alone. MRI is highly sensitive, but not specific for the presence of impingement and rotator cuff injury. MRI is also useful in the evaluation of avascular necrosis, biceps tendonitis and rupture, inflammatory processes, and tumors [21].
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