CMS200 Shoulder Pain PDF

CMS200 Shoulder Pain Module  Learning Outcomes Evaluate the etiology, epidemiology, and risk factors for common shoulder conditions, including rotator cuff disorders, shoulder impingement syndrome, frozen shoulder, and shoulder instability. Distinguish the essential feat...

CMS200 Shoulder Pain Module  Learning Outcomes Evaluate the etiology, epidemiology, and risk factors for common shoulder conditions, including rotator cuff disorders, shoulder impingement syndrome, frozen shoulder, and shoulder instability. Distinguish the essential features of diagnosis, common symptoms, and signs associated with each shoulder condition. Conduct a thorough patient history interview, and perform a comprehensive physical examination of the shoulder, including specific tests for each condition. Analyze imaging findings and evaluate the role of imaging in diagnosing shoulder conditions. Construct a differential diagnosis based on patient history, physical examination, and imaging findings.  Learning Outcomes Decide when to refer a patient for specialist care, and appreciate the importance of patient education and shared decision-making in managing shoulder conditions. Examine the natural history, prognosis, and potential complications associated with each shoulder condition. Diagnose acute and chronic shoulder problems, including fractures, dislocations, strains, and sprains. Distinguish between referred pain from the neck or other regions and localize the source of shoulder pain. Monitor and assess patients with shoulder conditions for response to treatment and potential complications.  Epidemiology of Shoulder Pain Shoulder pain is the third most common musculoskeletal reason for seeking medical care, affecting between 7% and 26% of adults at any time. Most shoulder complaints arise from Intrinsic Causes- involving articular and periarticular structures. Extrinsic Causes involving neurologic disorders or visceral conditions may refer pain to the shoulder. Cervical spine disease is the most common cause of referred pain to the shoulder. The prevalence of symptomatic rotator cuff disorders increases with age, occurring in about 2.8% of those older than 30 years and in 15% of those older than 70 years.  Diagnostic Approach The first step in assessing shoulder pain is to consider intrinsic versus extrinsic causes. For intrinsic causes the shoulder pain should increase with shoulder and arm movement. If the pain is not quite related to shoulder and arm movements then extrinsic causes must not be overlooked. One would then focus their inquiries to rule in or out neurologic causes; that for the shoulder are usually cervical, or thoracic processes that may be the extrinsic source. There are also abdominal causes of extrinsic pain such as from the gallbladder.  Diagnostic Approach For intrinsic causes; determine whether there was any trauma. If there was trauma; fracture, dislocation then tears of the rotator cuff or labrum should be considered. If there was no trauma that preceded the shoulder pain, then one should determine whether the pain occurs with only active range of motion (which stresses the muscles, tendons, and ligaments) Consider soft tissue disorders such as rotator cuff or biceps tendonitis, rotator cuff tendinopathy/tears, or subacromial bursitis.  Diagnostic Approach Pain with active and passive motions suggests involvement of the glenohumeral joint (eg, osteoarthritis, frozen shoulder, gout, osteonecrosis) or AC joint disease (eg, separation or osteoarthritis). Pain with elevation of arm above the head suggests impingement syndrome. Pain on lifting items with the biceps or pain with wrist supination suggests biceps tendinitis.  Intrinsic causes of shoulder pain Impingement syndrome/rotator cuff tendinitis(includes full and partial rotator cuff tears): 48%-85% prevalence Calcific tendinitis: 6% prevalence Biceps tendinitis/long head Glenohumeral instability Acromioclavicular syndromes Frozen shoulder/capsulitis: 16%-22% prevalence Glenoid labrum tear Prevalence reported is in the primary care setting not the general population  Intrinsic causes of shoulder pain Inflammatory arthritides including rheumatoid, crystal associated, reactive etc. Infection of joint or soft tissues Osteoarthritis Polymyalgia rheumatica Osteonecrosis According to Keenan CR, Blotzer J.; the prevalence in the primary care setting is unknown if not indicated and in one study, 77% of patients had more than one diagnosis  Causes of extrinsic shoulder pain Chest disorders Myocardial infarction Angina pectoris Pericarditis Aortic dissection Pulmonary embolism Pneumothorax Pneumonia Pleuritis Pancoast tumour Mesothelioma Mediastinal or lung neoplasm  Causes of extrinsic shoulder pain Abdominal and pelvic disorders Left shoulder pain: Splenic infarction Splenic rupture Right shoulder pain Hepatic abscess Cholecystitis Hepatic hematoma Left and/or right shoulder pain: Subphrenic abscess Intra-abdominal hemorrhage Ruptured abdominal viscus  Causes of extrinsic shoulder pain Neurologic disorders Cervical radiculopathy Brachial plexopathy Entrapment neuropathy Herpes zoster Cervical spinal stenosis Thoracic outlet syndrome  Causes of extrinsic shoulder pain Esophageal disease Aneurysm Peptic ulcer Pancreatitis Abdominal neoplasms Ectopic pregnancy Vascular insufficiency including: Arteritis Venous thrombosis Rotator Cuff Disease  Rotator cuff disease RCD Rotator cuff disease (RCD) consists of tendinopathy of one or more of the four rotator cuff muscles, full- or partial-thickness tears of these rotator cuff tendons, or bursitis of the sub acromial bursa. Tendinopathy is a broad term for conditions of the tendon that cause swelling and pain. Tendinopathy and tendonitis are often used interchangeably. Even though they have almost identical symptoms, they're different conditions. Tendinopathy is a degeneration of the collagen protein that forms the tendon while tendonitis, is an inflammation of the tendon.  Rotator cuff disease RCD The majority of patients with RCD improve with non-operative treatment. Some patients with full-thickness rotator cuff tears can compensate to recover function with non-operative treatment, even though the tear does not heal without surgery. Smaller tears are less likely to propagate, larger tears tend to progress with time and eventually may become irreparable because of significant tendon retraction, muscle atrophy, or both or when tendon tissue quality does not allow repair. One study of asymptomatic shoulders detailed that partial rotator cuff tears were present in 20% of the population, and 15% had full-thickness tearing.  Tendinopathy Rotator cuff tendons experience structural changes over the years secondary to repetitive contact of the tendons with movements between the acromioclavicular arch and the humeral head and between the joint capsule and the glenoid rim. The tendons undergo progressive histological changes that start in reactive tendinopathy and continue into tendon disrepair and degenerative tendinopathy and end in tendon rupture. Initially those changes are reversible but shift to degeneration and rupture when the capacity of the tissue to repair is not enough. Our role is to be sensitive enough to depict changes that are reversible.  Tendinopathy Initially the reaction of the tendon to load, friction, and activity results in small changes with disorganized extracellular matrix and subtle inflammatory reaction around the tendon that can be seen on imaging as peritendinitis and focal thickness of the tendon on high-resolution MR or US. Progressive histological changes include: mucoid degeneration, chondral metaplasia, and amyloid deposition together with reparative changes and inflammation such as an increase of fibroblastic cells and neovascularization. These changes represent degenerative tendinopathy, and they are precursors of tendon tears.  Partial Tears The incapacity to heal and restore the normal histological structure of the tendon leads to partial tear with scar formation that decreases mechanical properties. Tears that are bigger than 50% have a higher probability to progress to a full-thickness tear than those that are smaller than 50% of the thickness. Tears that are smaller than 50% are usually treated conservatively; surgical treatment is only recommended when conservative measures fail.  Partial Tears Assessing the shoulder for partial tears in a clinical setting is challenging. One can infer from an examination that there may be a possibility of a tear, however this can only be confirmed by imaging such as; ultrasound or MRI. A complete tear is commonly associated with a positive Drop Arm test however this may be positive because of the pain lowering the arm in an intact inflamed tendon without a tear. So this can create a diagnostic conundrum and be a bit frustrating initially in practice. Bursal-side tears are associated with subacromial and coracohumeral arch degenerative changes. Because of their adequate blood supply, they have a tendency to heal. Partial articular surface tears are the more frequent; they have been named as PASTA (partial articular supraspinatus tendon avulsion). They don’t heal properly and have a tendency to progress to full-thickness tears. Insertional tears occur in younger population and are related to traumatic events.  Full-Thickness Tears Full-thickness tears are those tears that extend from the articular side to the bursal side. The size of the tear, the number of tendons affected, the retraction, and the shape of the tear will affect the prognosis. Most tears are found in supraspinatus, however; subscapularis tendon tears are more frequent than previously thought. They have been found in more than 30% of cadavers. Fat atrophy has implication on the therapeutic approach and patient prognosis. If the atrophy is greater than 50% of the muscle, there is a high rate of recurrence after surgical repair. Fat atrophy is something that is picked up and described in a MRI report.  Massive Rotator Cuff Tears, Rotator Cuff Arthropathy A massive rotator cuff tear is characterized by the involvement of two or more tendons or a retraction greater than 5 cm. There is progressive migration of the humeral head superiorly. Glenohumeral arthrosis can be seen as loss of the joint space and presence of inferior humeral osteophytes. In the later stages on imaging, there is subchondral cyst formation, secondary areas of avascular necrosis and bone marrow edema, and ultimately collapse of the humeral head.  Etiology and Risk Factors Excessive overloading, chronic repetitive injuries with overhead movement and lifting Instability of the glenohumeral and acromioclavicular joints Muscle imbalance Adverse anatomical features (narrow coracoacromial arch and a hooked acromion) Rotator cuff degeneration with aging Ischemia Musculoskeletal diseases that result in wasting of the cuff muscles. Acute injuries related to falls on an outstretched arm or to pulling on the shoulder  Clinical Presentation During the examination, one should consider/evaluate intrinsic/extrinsic causes of shoulder pain. Shoulder and arm pain/weakness is the most common symptom of RCD, especially during overhead activities. This is usually described as a dull pain becoming sharp during overhead motion.  Clinical Presentation The pain is often felt in the distribution of the deltoid muscle to its insertion at the deltoid tuberosity. Other symptoms include: night pain, weakness, stiffness, or crepitus heard during shoulder movement. The presence of pain is not required to diagnose RCD, as a chronic full-thickness rotator cuff tear may present with painless loss of active motion.  Physical Examination Physical examination includes inspection, palpation, range of motion, strength and provocative shoulder tests. The neck and the elbow should also be examined to exclude the possibility that the shoulder pain is referred from either of these regions.  Inspection This includes observing the way the patient moves and carries the shoulder. The patient should be properly disrobed to permit complete inspection of both shoulders. Swelling, asymmetry, muscle atrophy, scars, ecchymosis and any venous distention should be noted. Venous distention for example may indicate an extrinsic cause for the shoulder pain such as venous thoracic outlet syndrome. Deformity, such as squaring of the shoulder that occurs with anterior dislocation or a step defect at the AC joint could suggest a diagnosis. Scapular “winging,” can be associated with shoulder instability and serratus anterior or trapezius dysfunction. Atrophy of the supraspinatus or infraspinatus should prompt a further work-up for such conditions as rotator cuff tear, suprascapular nerve entrapment or neuropathy.  Palpation Palpation should include examination of the: Acromioclavicular and sternoclavicular joints, cervical spine and the biceps tendon. The anterior/posterior glenohumeral joint, coracoid process, acromion and scapula should also be palpated for any tenderness and deformity.  Range of Motion Testing The complex series of articulations of the shoulder (SC/AC joints, glenohumeral joint and the scapulothoracic joint) allows a wide range of motion, therefore the affected extremity should be compared with the unaffected side to determine the patient's normal range. Active and passive ranges should be assessed. Shoulder abduction involves the glenohumeral joint and the scapulothoracic articulation. Glenohumeral motion can be isolated by holding the patient's scapula with one hand while the patient abducts the arm. The first 20 to 30 degrees of abduction should not require scapulothoracic motion. With the arm internally rotated abduction continues to 120 degrees. Beyond 120 degrees, full abduction is possible only when the humerus is externally rotated.  Range of Motion Testing Apley scratch test is useful to assess shoulder range of motion. Abduction and external rotation are measured by having the patient reach behind the head and touch the superior aspect of the opposite scapula. Internal rotation and adduction of the shoulder are tested by having the patient reach behind the back and touch the inferior aspect of the opposite scapula (T8 level). External rotation should be measured with the patient's arms at the side and elbows flexed to 90 degrees. Range of Motion Testing Evaluating the Rotator Cuff-strength and provocative shoulder tests Clinical tests for RCD can be divided into pain provocation tests and strength tests. Pain provocation tests are considered positive if shoulder pain is induced when the rotator cuff and subacromial bursa are compressed between the humeral head, acromion, or coracoid process. Well known pain provocation tests are the painful arc of abduction (next slide), Neer test and the Hawkins test for subacromial impingement.  Clinical Tests for Rotator Cuff Disease Pain provocation tests Cross body adduction Neer Painful arc Passive abduction Hawkins Yocum  Likelihood Ratio (LR) Diagnostic or screening tests are often described using sensitivity and specificity. Likelihood ratios are alternative statistics for summarizing diagnostic accuracy, which have several particularly powerful properties that make them more useful clinically than other statistics. A LR greater than 1 indicates that the test result is associated with the presence of the disease, whereas a likelihood ratio less than 1 indicates that the test result is associated with the absence of disease. The further LRs are from 1 the stronger the evidence for the presence or absence of disease. LRs above 10 and below 0.1 are considered to provide strong evidence to rule in or rule out diagnoses respectively in most circumstances. Crossover or crossed body adduction test Adduct the patient's arm across the chest. Pain with adduction is a positive test for AC joint involvement, with a positive LR of 1.9 and a negative LR of 0.42. Acromioclavicular joint tenderness and compression tenderness have low LRs so are not diagnostically helpful. Sensitivity is 75%, specificity is 61%.  Neer impingement sign/test Performed by flexing the shoulder maximally in an overhead position. Positive test: Pain is reproduced with full passive shoulder flexion. Sensitivity is 79%; specificity is 53%. Pain during this maneuver is a positive test for a subacromial impingement/rotator cuff tendinitis disorder, with a positive LR 1.0 to 1.6 and a negative LR 0.60.  Painful arc of abduction Shoulder pain from 60° to 120° is a positive test for a subacromial impingement/rotator cuff tendinitis disorder, with a positive LR 3.7 and a negative LR of 0.36. Sensitivity is 71%, specificity is 81%.  Hawkins impingement sign/test Perform with the shoulder forward flexed 90 degrees and the elbow flexed at 90 degrees. The shoulder is then maximally internally rotated to impinge the greater tuberosity on the undersurface of the acromion. Positive test: Pain is reproduced by this maneuver. Sensitivity is 79%; specificity is 59%. Pain during this maneuver is a positive test for supraspinatus impingement/rotator cuff tendinitis, with a positive LR of 1.5. When both the Hawkins and Neer signs are absent, the negative LR is helpful at 0.1.  Passive Abduction Examiner passively brings shoulder into full abduction. Positive test: Pain is reproduced by this maneuver and is a positive test for supraspinatus impingement/rotator cuff tendinitis. Sensitivity is 74%; specificity is 10%. Positive LR of 0.82 negative LR is 2.6.  Yocum Test Patient flexes their elbow and places their hand on the contralateral shoulder. The patient elevates the elbow without raising ipsilateral shoulder. Pain indicates rotator cuff or subacromial bursal impingement with a positive LR 1.3 and a negative LR of 0.53. Sensitivity is 79%, specificity is 40%.  Clinical Tests for Rotator Cuff Disease: Strength Tests Drop arm test Dropping sign External rotation lag Internal rotation lag Gerber (lift off test)  Drop arm test (supraspinatus) Passively abduct the patient’s arm to 90 degrees and then instruct them to lower it slowly. Positive test: Immediate pain and the patient “drops” the arm as they are unable to lower it slowly. Weakness during this maneuver is a positive test for a supraspinatus rotator cuff tear or bicipital tendinitis, with a positive LR of 3.3 and negative LR of 0.82. Sensitivity of 24% and specificity of 93%.  Dropping Sign The shoulder is abducted 90 degrees and the elbow is flexed 90 degrees and the shoulder is externally rotated, alternatively the test could be done with the elbow by their side and in both instances the examiner resists external rotation by the patient. Pain and or weakness suggests infraspinatus involvement (tear/RCD) with a positive LR of 3.2 and negative LR of 0.35. Sensitivity of 73% and specificity of 77%.  External Rotation Lag Test Strength testing can produce weakness, pain, or both, especially when the patient has a partial rotator cuff tear. Inability of the patient to maintain external rotation (external lag test)is a positive test for supraspinatus and infraspinatus disorders, with a positive LR of 7.2. Sensitivity of 47% and specificity of 94%.  Internal Rotation Lag Test Inability of the patient to hold the hand in this internal rotation lag position is positive test for a subscapularis disorder, with a positive LR of 5.6 to 6.2 and an excellent negative LR of 0.04. Sensitivity of 97% and specificity of 83%.  Gerber Lift Off Test The starting position for this test is the same as the one for the internal rotation lag test. The examiner offers resistance against the patient’s hand as they lift the hand away from their back. The test is positive if they are unable to lift the hand away from the back by internally rotating the arm. Positive LR of 1.4-1.5 and negative LR of 0.63-0.85. Sensitivity of 34-68% and specificity of 50-77%.  Clinical Tests for Rotator Cuff Disease: Composite tests for pain and weakness External rotation resistance Full can test Resisted abduction Empty can (Jobe) Patte  External rotation resistance test Pain or weakness during this maneuver is a positive test for an infraspinatus disorder, with a positive LR of 2.6 and negative LR of 0.49. Sensitivity of 63% and specificity of 75%  Empty/Full Can Tests Both tests assess lesions of the supraspinatus muscle and tendon, although these tests can also engage other muscles about the shoulder such as infraspinatus and upper subscapularis, upper, middle and lower trapezius, serratus anterior, anterior, middle & posterior deltoid. The Empty Can test has a sensitivity of 71%, specificity of 49% and a LR of 1.3 and negative LR of 0.64 The Full Can test has a sensitivity of 75%, specificity of 68% and a LR of 2.4 and negative LR of 0.37  Resisted Abduction and Patte Resisted abduction Arm abduction 90°, examiner applies downward pressure, pain/weakness suggests impingement. This test has a sensitivity of 58%, specificity of 20% and a LR of 0.72 and negative LR of 2.1 Patte Arm in 90° abduction, elbow in 90° flexion, external rotation against resistance of examiner; pain or muscle weakness during external rotation suggests infraspinatus/teres minor involvement. This test has a sensitivity of 58%, specificity of 60% and a LR of 1.4 and negative LR of 0.70  In Summary: Pain Provocation Tests A positive painful arc test result is the only 1 of 6 pain provocation results that were and that has an LR greater than 2.0. Positive results on the Hawkins test: LR, 1.5 or Neer test: LR range, 0.98-1.6 had little value. A normal result on the painful arc test was the only finding with a negative LR less than 0.50 (negative LR, 0.36), although the absence of pain on the Hawkins test came close to that threshold ( negative LR: 0.51)  In Summary: Strength Tests Of the 5 strength tests evaluated in studies for detecting a full rotator cuff tear, a positive external rotation lag test result LR, 7.2 and internal rotation lag test positive LR 5.6 were the most accurate strength tests for a full rotator cuff tear. The internal rotation lag test was the most accurate finding when negative (negative LR, 0.04. A positive drop arm test result increased the likelihood of any RCD positive LR, 3.3.  In Summary: Composite Tests Composite tests are positive when the patient experiences either pain or weakness during the maneuver. When positive, the external rotation resistance test LR, 2.6 was an accurate composite finding, whereas the absence of pain or weakness identified patients less likely to have RCD; LR 0.49.  In Summary: Accuracy of Combinations of Clinical Tests for RCD Because of the relatively low diagnostic accuracy of commonly performed individual tests, combinations of findings for RCD have been evaluated. A positive Hawkins test result together with a positive Neer test result LR, 1.6 has substantial overlap compared with the individual tests. Among a smaller set of 5 findings designed to detect RCD, a study showed a positive LR of 2.9 for 3 or more positive findings (Hawkins test, Neer test, external rotation resistance test, empty can test, painful arc test), whereas fewer than 3 positive findings conferred an LR of 0.34.  What does it all mean? Positive findings on the internal and external rotation lag tests and presence of a painful arc have the highest positive LR for RCD and rotator cuff tears. Most experts consider RCD more likely with increasing numbers of positive findings. Rotator cuff disease is considered much less likely when the findings on more tests are normal.  What does it all mean? For patients with shoulder pain, it‘s recommended one perform a single pain provocation test (painful arc test), 3 strength tests (internal rotation lag test, external rotation lag test, and drop arm test), and 1 composite test (external rotation resistance test). Based on the available evidence, a positive painful arc test finding along with other positive findings suggests an LR of 3.7 or greater. Using the population prevalence of RCD, which increases with age (2.8%-15%), the probability of disease would be 9.6% (for patients older than 30 years) to more than 40% (for patients 70 years and older).  What does it all mean? Among patients referred to shoulder specialists, the prior probability of RCD is much higher (>30%),which means that the presence of pain during the painful arc test in those patients confers a more than 60% probability of disease. Because of the high probability of disease among patients referred to shoulder specialists, the absence of pain during a painful arc test in a referred patient does not rule out RCD, because the probability could still be as high as 13%.  Imaging RCD The plain film/X ray is the first-line imaging modality for nearly all shoulder pathology. They are also often the only imaging examination necessary for evaluating calcific tendinitis, arthritis, acute shoulder trauma, and osteolysis of the distal clavicle in athletes. Plain X rays/radiographs can be useful in visualizing rotator cuff tears because of degenerative changes which can appear between the acromion and greater tuberosity of the shoulder. Certain views can show a superior elevation of the humeral head in relation to the center of the glenoid. A high riding humeral head is likely consistent with a tear of the supraspinatus tendon of the rotator cuff. (next slide) Imaging RCD  Imaging RCD Radiographic views of the Supraspinatus outlet allow evaluation of the shape of the acromion as acromial spurs are associated with a higher incidence of rotator cuff tears. The acromioclavicular joint views evaluates for the presence of acromioclavicular joint arthritis, which can mimic rotator cuff tears, and for spurs that can cause rotator cuff injuries.  Imaging RCD CT of the shoulder is reserved for evaluating a fracture or fracture-dislocation and a prosthetic joint. The CT scan can demonstrate fracture displacement, angulation/complexity and can aid in any preoperative planning. MRI is the primary imaging modality used to evaluate soft tissues of the shoulder. Soft tissues include; the rotator cuff, tendons, biceps muscle, subacromial and subdeltoid bursae. MRI also has a high level of sensitivity in detecting subtle fractures, acromioclavicular joint changes, erosive changes to the distal clavicle, early avascular necrosis, bone marrow edema, muscular atrophy, and morphology of the acromion.  Imaging RCD Radionuclide bone scans, are typically used for evaluating an infection post arthroplasty or suspected metastases and whole-body imaging.  Ultrasound vs. MRI in imaging RCD Studies suggest that MRI or ultrasound could equally be used for detection of full-thickness rotator cuff tears. Ultrasound may be better at picking up partial tears and it is usually more cost-effective for identification of full- thickness tears vs. MRI. Some tears such as intra-substance rotator cuff tears would be unlikely to be repaired even when detected. Not all patients with full-thickness tears will undergo surgery, particularly if they do not experience sufficiently severe symptoms.  Rotator Cuff Tendinopathy With rotator cuff tendinopathy imaging can demonstrate an increase in tendon thickness on MRI. (star) MRI showing delaminating partial tendon rupture with fluid between the different layers without disruption of its articular side insertion Two different cases on coronal MRI. (a) Articular side partial (arrows) rupture of more than 50% of tendon thickness; (b) bursal side partial rupture (arrows) affecting less than 50% of the tendon thickness Coronal MRI of a full-thickness tear of the supraspinatus. Coronal MRI of a massive rupture of the rotator cuff showing superior migration of the humeral head (black arrow), remodeling of the acromioclavicular arch (black arrow head), gleno-humeral degenerative changes, and fatty atrophy of the supraspinatus (*)  Shoulder Arthrogram Glenohumeral arthrography was described in 1933 by Oberholzer when he injected air into the shoulder joint to evaluate the structures, including the axillary recess, on a conventional radiograph. In 1934, Codman had suggested that injecting contrast material into the shoulder joint could demonstrate rupture within the rotator cuff.  Shoulder Arthrogram The use of iodinated contrast, computed tomography, and magnetic resonance imaging naturally came after this time. Currently, MRI is the first-line imaging modality for assessing joints as it has a superior soft-tissue contrast capability. MR arthrography, or MRA, is the gold standard in evaluating a suspected labral tear or shoulder instability. CT can be performed if there are contraindications to MRI or the patient is claustrophobic. The arthrogram can aid in facilitating the identification of ligamentous or tendon injuries, intraarticular "loose" bodies, cartilage or synovial abnormalities, loosening of the joint prosthesis, and sinus tracts. MRI arthrography of the coronal shoulder demonstrating full-thickness complete rupture of the supraspinatus  Prognosis The prognosis of shoulder pain depends on the nature of the specific problem. Periarticular disorders, such as impingement, may be self-limited and respond to rest, analgesics, and range of motion and strengthening exercises. Impingement syndrome can be chronic and recurrent, leading to rotator cuff tendinopathy. This can ultimately progress to full-thickness rotator cuff tears and secondary glenohumeral osteoarthritis. By middle age, asymptomatic rotator cuff tears are common. Large tears can often lead to loss of abduction and decreased strength and function; these patients should be referred to a specialist.  Prognosis With regards to prognosis, a significant portion of untreated supraspinatus tendonitis may go on to rotator cuff tears. In some patients, these early changes may be subclinical and may not present until the tear has been present for some time. A significant portion of rotator cuff defects enlarge and became symptomatic over time. This natural history of tears leads us to believe that patients presenting with rotator cuff tendonitis may benefit from early non-surgical interventions, to improve their prognosis.  Prognosis Partial rotator cuff tears may heal with non-operative treatment. Most partial rotator cuff tears can be treated with physical therapy and scapular and rotator cuff muscle strengthening. However, research suggests that 40% of the partial thickness tears progress to full­thickness tears in 2 years. Physical therapy can strengthen the remaining muscles to compensate for loss of strength and can have high rate of success for chronic tears. Physical therapy is also an option for older sedentary patients. Full ­thickness rotator cuff tears do not heal well and have a tendency to increase in size with time; 49% of the tears get bigger over an average of 2.8 years. April 2019 September 2023  Prognosis When tears get larger, they are also associated with worsening pain. Fatty infiltration is a degenerative process where muscle is replaced by fat following injury to the rotator cuff tendons. Fatty infiltration progresses in full ­thickness rotator cuff tears, and is a negative prognostic factor for successful surgical treatment. Fatty infiltration is an irreversible process so operative interventions are usually performed when the degree of infiltration is low.  Prognosis Most young active patients with acute, full­thickness tears should be treated with operative fixation. Full thickness subscapularis tendon tears should undergo surgical repair since untreated tears usually lead to premature osteoarthritis (OA) of the shoulder. Nonetheless, physical therapy is indicated for atraumatic degenerative rotator cuff tears and success can be as high as 70%. That said, long ­- term (10­year) outcome studies show that surgical repair of rotator cuff tears can result in better outcomes than physical therapy alone.  Differential Diagnosis The differential diagnosis of rotator cuff RCD/tendinitis/tendinopathies should include: Subacromial impingement, rotator cuff tear (partial versus full-thickness), bicipital tendonitis, glenohumeral arthritis, acromioclavicular arthritis. Note that many of these occur as a continuum of supraspinatus tendonitis and can occur concomitantly. Other entities that clinically can mimic rotator cuff lesions. Calcified tendinopathy Adhesive capsulitis Nerve denervation syndromes Isolated greater tuberosity fractures  Calcified Tendinopathy Crystal deposition, especially CPPD (Calcium Pyrophosphate Dihydrate Deposition Disease) deposits on the tendon, causes inflammation and is an important cause of shoulder pain in young adults. Its cause is still unknown although microtrauma, ischemia, and metaplasia have been proposed as causes. It is usually a self-limited disease with spontaneous resolution in a high percentage of cases.  Calcified Tendinopathy Different clinical stages have been described: a precalcification phase which is clinically silent; the calcification phase in which crystal deposition occurs, subsequently the start of a resorptive phase with inflammatory reaction that causes severe pain; and the end a post- calcification phase. The deposits of CPPD might migrate to the subacromial bursa causing bursitis or less frequent into the bone at the lesser or greater tuberosity. It is important to know this potential involvement of the numeral head to avoid confusion with a tumor. Intrabone migration of hydroxyapatite deposition, AP radiographs (below left) demonstrate calcifications in the greater tuberosity surrounded by a radiolucency area (*). Calcifications within the rotator cuff space help for the diagnosis of hydroxyapatite deposition disease (black arrow). MRI (below right) shows the same features of calcifications within the greater tuberosity (*) surrounded by a hyperintense halo (arrow)  Adhesive Capsulitis Adhesive capsulitis is a clinical diagnosis characterized by pain and marked decrease of the range of motion, especially to external rotation. In the acute inflammatory phase, MRI can show axillary capsular thickening and capsular edema. Progressively hypervascularization and fibrosis occur, which may be reflected on MRI images by thickening of the coracohumeral ligament, subcoracoid fibrosis, and capsular thickening. On MR arthrography classic findings are low volume injection of the contrast medium and thickening of the structures Patient with decreased external rotation, MRI shows thickening of the coracohumeral ligament with soft tissue edema  Nerve Denervation Syndromes Suprascapular neuropathy can be related to compression of an associated paralabral cyst in a superior labrum injury. When there is no compression, there are two main origins: a viral inflammation and or overuse in athletes with overhead activities. On imaging in the acute phase, supraspinatus and infraspinatus muscle edema is seen, whereas in chronic phases fatty atrophy and volume loss of the muscle are shown.  Nerve Denervation Syndromes Axillary nerve denervation can be secondary to injury of the axillary nerve in anterior inferior shoulder dislocation especially in patients older than 40 years of age. It can also be secondary to compression due to a lesion in the quadrilateral space; or can be idiopathic. The role of MRI is to rule out compression causes and associated injuries in shoulder dislocation. MRI will demonstrate axillary nerve edema or fatty atrophy on chronic stages Axial MRI paralabral cyst (*) in the supraglenoid notch causing entrapment of the suprascapularis nerve and secondary edema in the infraspinatus (arrow)  Isolated Greater Tuberosity Fractures Isolated fractures of the greater tuberosity can be secondary to shoulder direct or indirect trauma or in older population to minor trauma in osteoporotic patients. When there is little or no displacement ( 25% to 50%) Medial LHB tendon subluxation/dislocation  Prognosis Patients with persistent, debilitating symptoms in the setting of known proximal biceps tendon pathology are good surgical candidates for either a tenotomy or tenodesis procedure. Biceps tenotomy means cutting off one tendon and not reattaching it.The biceps will still function well after tenotomy, but there may be a change in the appearance of the arm, “Popeye effect”. Biceps tenodesis is a where a surgeon removes a damaged section of the biceps and reattaches the rest of the tendon to the bone of the upper arm.  Biceps Tendon Rupture Etiology Distal biceps rupture is from the excessive eccentric force as the arm is brought into extension from flexion. These activities include weightlifting, wrestling, and labor- intensive job. Proximal biceps rupture is generally not due to a unique mechanism of injury but is highly correlated with rotator cuff disease. Risk factors include age, smoking, obesity, use of corticosteroids, and overuse. Rare causes include the use of quinolones, diabetes, lupus, and chronic kidney disease. Biceps Tendon Rupture  Biceps Tendon Rupture Epidemiology The incidence of distal biceps tendon rupture is around 2.55 per 100,000 patient-years. Most patients (more than 95%) are males, and injury events usually happen during middle age (35 years to 54 years). Rupture of the distal biceps mainly involves the dominant limb. However, proximal biceps rupture is commonly seen in elderly patients, and its exact incidence is unknown but is more common than distal biceps rupture.  Biceps Tendon Rupture Evaluation Diagnosis is often clinically made, while imaging is helpful when the diagnosis is unclear or partial rupture is considered. Three criteria described for diagnosis: History of a single traumatic event. The patient will report a sudden, painful pop whilst the elbow is eccentrically loaded from flexion to extension. e.g., while doing a biceps curl. Grossly palpable and visible signs of retraction of the biceps muscle belly( reverse popeye deformity) Weakness of flexion of the elbow and supination of the forearm in cases of distal biceps rupture.  Biceps Tendon Rupture Differential Diagnosis The diagnosis of the biceps tendon rupture sometimes is challenging. The investigator should bear in mind that proximal biceps tendon injury usually coexists with rotator cuff disorders and shoulder girdle instability. Differential diagnosis includes: Rotator cuff disease Shoulder dislocation/instability Impingement syndrome Humeral/radial head fracture  Biceps Tendon Rupture Prognosis Proximal biceps rupture patients generally recover with non-operative treatment and experience no long- term deficits in shoulder or elbow strength. Distal biceps rupture can cause persistent pain and forearm supination weakness. Also, with a complete distal biceps rupture, the tendon can retract significantly, and later repair in chronic cases would be technically challenging. Hence the timely diagnosis of distal biceps rupture is critical, especially in a young active patient.  Acromioclavicular Joint Injury Injury to the acromioclavicular (AC) joint is a common injury among athletes and young individuals. Epidemiology AC injuries are frequently seen in sporting events, car accidents, falls from a bicycle, and other sports-related activities (e.g. skiing). AC joint injuries may account for as much as 40% of all shoulder injuries and nearly 10% of all injuries in collision sports such as football, lacrosse, and ice hockey. (in the primary care setting not the general population)  Acromioclavicular Joint Injury Mild injuries are not associated with any significant morbidity, but severe injuries can lead to significant loss of strength and function of the shoulder. Acromioclavicular injuries may be associated with a fractured clavicle, impingement syndromes, and more rarely neurovascular insults. Pathophysiology The most common mechanism of injury is direct trauma to the lateral aspect of the shoulder or acromion process with the arm in adduction. Falling on an outstretched hand or elbow may also lead to AC joint separation  Acromioclavicular Joint Injury On examination, the clinician may observe swelling, bruising, or a deformity of the AC joint, depending on the degree of injury. The patient will be tender at that location. They may have a restriction in the active and passive range of motion secondary to pain. "Piano key sign" may be seen, with an elevation of the clavicle that rebounds after inferior compression. It is essential to evaluate the entire clavicle for possible fracture or sternoclavicular injury as well as perform a full neurovascular exam on the affected extremity.  Acromioclavicular Joint Injury Imaging Standard X-rays are adequate to make a diagnosis of acromioclavicular joint injury. Weighted stress views may be useful to evaluate the displacement of the joint when the diagnosis is uncertain on standard AP views. If there is continued uncertainty in diagnosis, the provider may also consider ultrasound or MRI for further diagnostic evaluation.  Acromioclavicular Joint Injury Acromioclavicular joint injuries follow a classification system of type I to type VI. Type I is referred to as a sprain of the acromioclavicular ligaments only and demonstrates no displacement. Type II involves tearing of the acromioclavicular ligament and sprain of the coracoclavicular ligament with less than 25% increase in the coracoclavicular interspace or with the clavicle elevated but not superior to the border of the acromion. Type I and II sprains are managed non-operatively with a sling, analgesia, ice, and physical therapy.  Acromioclavicular Joint Injury Type III AC joint separation involves tearing of both the acromioclavicular ligament and coracoclavicular ligaments resulting in clavicle elevation above the border of the acromion with a 25 to 100% increased coracoclavicular distance on x-ray compared to the contralateral side. Type III injuries are frequently managed non-operatively similar to type I and II; however, if the displacement is greater than 75%; the patient is a laborer, elite athlete, or concerned about cosmesis; or is not improving with conservative management, then surgical intervention may be considered.  Acromioclavicular Joint Injury Posterior displacement of the distal clavicle into the trapezius defines type IV injuries. Type V injuries have a superior displacement by more than 100% compared to the contralateral side. Type VI is rare and is an inferolateral displacement in a subacromial or subcoracoid displacement behind the coracobrachialis or biceps tendon. Type IV through VI injuries are typically managed surgically, and warrants referral to an orthopedic surgeon. Acromioclavicular Joint Injury  Acromioclavicular Joint Injury Grade III AC joint injury in a 23-year-old after a car accident. AP bilateral radiograph obtained with weights shows vertical diastasis of the left AC joint, with clavicular elevation relative to the acromion.  Acromioclavicular Joint Injury US image of the left AC joint shows superior displacement of the clavicle (*) relative to the acromion (arrowhead), with effusion distending the joint and elevating the superior capsule (arrow).  Acromioclavicular Joint Injury Type V AC injury in a 41-year-old security guard with pain and deformity after rolling down a 50-ft ravine during an assault. AP radiograph obtained with weighting shows marked widening of the left coraco-clavicular interval (black bracket) and the AC joint (white bracket). This high-grade injury involves superior displacement of the clavicle and inferior depression of the scapula.  Acromioclavicular Joint Injury Type VI injury where the clavicle is displaced inferior to the acromion. This injury type is exceedingly rare and typically associated with other injuries, and it requires surgical reduction. The suggested mechanism of injury is a severe blow to the superior clavicle, with the arm abducted and the scapula retracted.  Clavicular fractures Fractures of the clavicle are classified into distal (15%–20% of cases), midshaft (80%–85% of cases), and medial (