Acute Musculoskeletal Complaints: Introduction
Approximately 20% of all office visits to primary care providers involve musculoskeletal complaints. The purpose of this chapter is to survey the most common presenting complaints of the upper and lower extremities, highlighting the etiology, clinical findings, differential diagnosis, and evidence-based treatment options for each.
Upper Extremity
The term subacromial impingement defines any entity that compromises the subacromial space and irritates the enclosed rotator cuff tendons. Impingement can involve any of the structures within the subacromial space, and the term encompasses various entities from subacromial bursitis to rotator cuff calcific tendonitis and tendinosis. Often these entities arise in a similar fashion and may be difficult to differentiate.
Impingement syndrome is classified into external, internal, and secondary impingement. The most common form is external impingement, which is caused by compression of the rotator cuff tendons as they pass under the coracoacromial arch. Subacromial bursitis can develop subsequently and intensify the compression. Internal impingement is caused by fraying of the infraspinatus tendon where it contacts the posterior glenoid. This occurs while the arm is maximally abducted and externally rotated and is seen in athletes who participate in overhead and throwing activities. Lastly, secondary impingement is caused by glenohumeral instability. Diagnosis is made with a meticulous history and physical examination, and appropriate imaging.
Diagnosis of subacromial impingement is primarily clinical. The patient complains of dull shoulder pain of insidious onset over weeks to months. Less often, these symptoms arise following trauma. Pain is typically localized to the anterolateral acromion and radiates to the lateral deltoid. Pain is aggravated at night, by sleeping with the arm overhead or lying on the involved shoulder. Overhead activities, throwing motions, and activities in which the humerus is flexed with an inward rotation also exacerbate symptoms.
Physical examination usually reveals normal range of motion (ROM), although the patient may experience a painful arc of motion or pain upon approaching maximum internal rotation and forward flexion. Muscular weakness is sometimes seen in the supraspinatus muscle or the internal and external rotators of the shoulder. Supraspinatus strength (empty can test) is tested with the arm in 90 degrees of abduction and 30 degrees of forward flexion, with the thumb pointing downward. Decreased strength indicates a positive test. To differentiate weakness caused by pain from actual loss of strength, it may be necessary to perform a subacromial injection with an anesthetic to alleviate the pain variable.
Radiographs that may aid in diagnosis include anteroposterior (AP), outlet, and axillary views of the affected shoulder. Curvature of the acromion or acromial spurs can be seen on an outlet view and may contribute to compression of the rotator cuff musculature or subacromial impingement.
Provocative testing includes the Neer test and the Hawkins-Kennedy test. The Neer test involves passive elevation of an internally rotated, forward-flexed arm. In the Hawkins-Kennedy test, the arm is positioned in 90 degrees of forward flexion and is internally rotated with a bent elbow. This causes impingement of the supraspinatus tendon against the anterior inferior acromion. Pain with either maneuver is considered a positive test; however, these tests may also be positive in patients with other pathology.
Differential diagnosis includes acromioclavicular joint arthritis, osteolysis of the distal clavicle, rotator cuff tear, cervical disc herniation, adhesive capsulitis, supraspinatus nerve entrapment, glenohumeral instability, and arthritis.
Treatment is initially conservative, using modified activity and nonsteroidal anti-inflammatory drugs (NSAIDs). The goal is to relieve inflammation, reestablish pain-free ROM, prevent atrophy, and enable return to previous activity. Current evidence supports the use of physical therapy to initiate rotator cuff and scapular musculature strengthening and joint mobilization techniques. A subacromial corticosteroid injection can also relieve symptoms when used with muscular strengthening. Surgical intervention is considered only after failure of conservative treatment.
Calcific tendonitis of the shoulder is an acute or chronic condition caused by inflammation around calcium deposits adjacent to the rotator cuff tendons. It affects about 10% of the population and is more common in women and in individuals older than 30 years.
Onset is usually abrupt and severely limits activities. It is theorized that the disease becomes painful only when the calcium is undergoing resorption; therefore, the patient may be pain free initially. The diagnosis is clinical; it is based on a history of shoulder pain similar to impingement along with abrupt onset and tenderness over the greater tuberosity.
Radiographic evidence of a calcified tendon is best seen on plain films. To localize the calcification, it is recommended that the radiographic views include AP, internal and external rotation, scapular Y (or outlet), and axillary views. Magnetic resonance imaging (MRI) is not routinely indicated.
Initial treatment consists of NSAIDs for a few weeks. A referral for physical therapy should be made to maintain ROM, and therapeutic ultrasound may be effective in reducing pain. In patients with signs of impingement, a subacromial corticosteroid injection may also be beneficial.
Rotator cuff tears have been noted in 5%-39% of people examined in cadaver and MRI studies. Their prevalence increases with age. The exact cause and best treatment are still being explored.
The rotator cuff complex is made up of four muscles: the subscapularis, supraspinatus, infraspinatus, and teres minor. Biomechanically, the rotator cuff abducts the arm with the assistance of the deltoid and also acts to rotate the humerus with respect to the scapula. The supraspinatus, infraspinatus, and teres minor externally rotate the humerus, while the subscapularis acts as a strong internal rotator. Together, the rotator cuff muscles contract to maintain the humeral head in the glenoid during movement and thus maintain shoulder stability.
Many rotator cuff tears are asymptomatic. If symptoms are present, patients describe pain, stiffness, and occasional weakness around the shoulder. The pain is located at the front of the shoulder and radiates down the arm. It may be aggravated by overhead activity or sleeping on the affected side. Generally, pain is worse with resisted muscle activity in patients with a partial-thickness rotator cuff tear. Those patients with a full-thickness tear may exhibit only muscular weakness without pain.
Careful examination may demonstrate subtle atrophy of the supraspinatus and infraspinatus muscles, which is a sign of advanced disease. Tenderness at the insertion site of the supraspinatus tendon (just below anterolateral acromion) is common. Occasionally, with a complete tear, a defect can be palpated.
Limitations in ROM are caused by muscle weakness and pain. Full-thickness tears are characterized by a decrease in active abduction, but normal passive ROM. Although quite variable, there is usually pain and slight weakness in patients with partial-thickness rotator cuff tears, and weakness without pain in patients with full-thickness tears. The supraspinatus muscle is often weak in patients with a tear (positive empty can test).
Patients often describe a “painful arc” (pain or weakness between 60 and 120 degrees of abduction). With a complete tear, patients may also demonstrate a “drop arm sign” (the arm dropping from abduction) because there is no muscle to control the arm as the patient brings the raised arm back to the side.
Plain films can be useful to rule out other causes of shoulder pain (eg, calcific tendonitis or osteoarthritis). Changes seen on plain films that may be consistent with rotator cuff disease include loss of space between the humeral head and acromion, acromial spurs, and sclerosis with cystic changes in the greater tuberosity. Ultrasound can diagnose a rotator cuff tear (91% sensitive) if read by a skilled radiologist, but MRI is considered the gold standard in the diagnostic imaging of rotator cuff disease.
Treatment focuses on pain management using NSAIDs. Patients should be referred for physical therapy early in order to take advantage of pain-reducing modalities such as heat, cold, and ultrasound. Flexibility and strengthening of the shoulder (rotator cuff muscles), scapula, and surrounding musculature are also helpful in treatment. Patients should be advised to avoid movements and activities that provoke symptoms.
Once a rotator cuff tear has been confirmed, referral should be made to an orthopedic surgeon. There is some evidence of improved results with surgical repair for both partial- and full-thickness tears. Patients with acute tears tend to have better outcomes than patients who have had pain for more than 6 months.
Disorders of the biceps tendon have been labeled as either tendonitis or overuse syndromes (tendinosis). Biceps tendonitis is an inflammatory process involving the portion of the tendon located in the intertubercular groove. Tendinosis is an overuse injury that begins with an influx of inflammatory cells and progresses to exudation of fluid into the tendon sheath. In either case, this tissue thickens and becomes more painful. Many investigators believe that biceps tendonitis is secondary to shoulder impingement and rarely occurs alone. Alternatively, some consider biceps tendonitis to be secondary to biceps tendon instability in the bicipital groove which, if present, is usually associated with subscapularis tendon pathology.
Patients typically complain of pain in the bicipital groove at the anterior aspect of the shoulder. The pain can radiate toward the deltoid insertion and it may be difficult to distinguish biceps tendon pathology from shoulder impingement or rotator cuff disease. Usually there is a history of repetitive overhead activity, which either initiates or aggravates symptoms. There may also be an audible or palpable “snap” at the bicipital groove during the arc of motion if instability is present.
The most common finding on physical examination is tenderness over the tendon within the bicipital groove. It is best localized when the arm is internally rotated to 10 degrees; at this angle, the biceps tendon is about 3 in. below the acromion.
Standard plain radiographs of the shoulder (AP, outlet, axillary views) are most often normal. For this reason, MRI should be considered (98% sensitive). An MRI-arthrogram may be ordered if there is high suspicion of an associated cartilaginous tear of the labrum.
Data supporting the sensitivity and specificity of provocative special tests of the biceps tendon are limited. The Speed and Yergason tests may, however, be used to assist in making the diagnosis of biceps tendonopathy. In the Speed test, the patient is asked to flex the arm against resistance with the elbow extended and forearm supinated. In the Yergason test, the patient supinates against resistance with the elbow flexed at 90 degrees. With either test, the presence of pain at the bicipital groove indicates a positive test.
Biceps instability is elicited by fully abducting and then externally rotating the patient’s arm. An audible or palpable snap detected at the bicipital groove as the tendon subluxes or dislocates is a positive result indicating biceps instability.
An injection of anesthetic into the subacromial space (not the biceps tendon sheath) can be used to aid in diagnosis and to help rule out rotator cuff tendonitis. Pain caused by biceps tendonitis will remain following injection.
Initial treatment of biceps tendonitis is conservative, consisting of NSAIDs, rest, and activity modification. Physical therapy is useful to strengthen the rotator cuff but should not be aggressive during the acute pain stage. Subacromial corticosteroid injections are also useful in the treatment of biceps tendonitis, but direct injection into the biceps tendon should be avoided.
Treatment of biceps instability is similar. Older, sedentary patients may benefit from conservative therapy, including injections; however, younger, more active patients should be referred promptly for surgical repair.
Ruptures of the proximal biceps tendon are most often found in association with rotator cuff tears, but isolated ruptures can occur.
History includes pain in the anterior shoulder just prior to a complete tendon rupture. At the time of rupture, the patient usually hears an audible “pop” followed by immediate relief of symptoms. There is commonly an associated tear of the cartilaginous labrum, so the patient may also complain of catching, popping, or locking of the shoulder.
Physical examination may reveal pain over the bicipital groove, bruising on the anterior aspect of the arm, and a “Popeye muscle” (particularly with biceps flexion) due to the distal retraction of the muscle mass.
Radiographs are usually normal. MRI can confirm biceps tendon rupture. Gadolinium-enhanced MRI is preferred if a labral tear is also suspected.
Treatment of an isolated rupture of the long head of the biceps is conservative and nonsurgical if the patient is inactive or would not be hindered significantly by loss of strength in the injured arm. Pain is managed with NSAIDs and modified activity, and activity is slowly advanced as tolerated. Physical therapy is useful to improve rotator cuff strength, if an associated rotator cuff tear is not present. If a labral or rotator cuff tear is suspected along with the rupture of the biceps long head, referral to an orthopedic surgeon is warranted.
Shoulder instability can be viewed as any condition in which the balance of various stabilizing structures in the shoulder is disrupted, resulting in increased humeral head translation. Most dislocations are anterior, but they can also be posterior and, on rare occasion, inferior. In younger patients, dislocations are most often caused by trauma and sports injuries, whereas in the elderly, falls are the predominant cause (usually accompanied by a fracture). This discussion focuses on anterior subluxation and dislocation.
Anterior instability is categorized using two acronyms: TUBS (traumatic, unidirectional, Bankart surgery) and AMBRI (atraumatic, multidirectional, bilateral, rehabilitation, inferior capsular surgery). TUBS describes the cause and the direction of instability. An avulsion of the anteroinferior glenohumeral ligament and labrum (Bankart lesion) is also seen with a probable avulsion fracture. Treatment for this type of instability is surgical repair. AMBRI describes an atraumatic mechanism and instability that is usually multidirectional and bilateral. This type of injury usually responds well to rehabilitation. If symptoms do not improve with rehabilitation, surgical repair (inferior capsular shift) is indicated.
The patient with a shoulder dislocation generally presents with shoulder pain, an unwillingness to move the affected arm, and a tendency to cradle the arm. The history usually includes a traumatic event, and a detailed description of the trauma—including arm position, energy level, and subsequent treatment adherence—is essential for diagnosis. Most subluxations and dislocations occur during abduction and maximal external rotation. Inspection reveals a bulge (due to the displaced location of the humeral head), as well as dimpling inferior to the acromion where the humeral head should be.
If the patient is not dislocated at the time of the examination, but the history details episodes of subluxation, the apprehension test should be performed. In this test, the patient is supine with the arm in 90 degrees of abduction; the examiner then applies an external rotation stress. Patient apprehension due to subluxation of the humeral head is considered a positive test. Posterior pressure on the proximal humeral head can provide relief of symptoms if shoulder instability is the cause of pain (relocation test).
Radiographs are required to confirm shoulder dislocations. AP and outlet views are standard; however, an axillary view shows the relationship of the humeral head to the glenoid fossa and is more accurate when assessing for dislocation. Occasionally a bony defect in the posterolateral portion of the humeral head (Hill-Sachs lesion) is seen radiographically.
Treatment for a shoulder dislocation consists of pain management and relocation. After relocation, the shoulder must be immobilized for 7-10 days to allow capsular healing. ROM exercises are then started, along with rotator cuff strengthening. Because younger patients with shoulder dislocations tend to have a high recurrence rate, surgical repair is warranted and early referral should be made in this population.
If the patient has signs of AMBRI, the standard treatment is a rehabilitation program to strengthen the rotator cuff and scapular musculature. If no improvements occur after rehabilitation, the patient should be referred for possible surgical repair.
De Quervain stenosing tenosynovitis involves the abductor pollicis longus and the extensor pollicis brevis of the thumb. Although once thought to be an inflammatory condition, recent evidence has shown that degeneration of the tendon is present. The condition can arise with repetitive activity that requires grasping with ulnar deviation or repetitive thumb use.
Diagnosis is largely clinical. Patients may complain of difficulty gripping items and often rub the area over the radial styloid. Pain is located on the radial side of the wrist and thumb, and occasionally radiates proximally.
There is tenderness to palpitation just distal to the radial styloid. Pain can also be reproduced with resisted thumb abduction and extension, or with thumb adduction into a closed fist and passive ulnar deviation (Finkelstein test). Pain over the tendons represents a positive test; however, the test may also be positive in patients with an arthritic flare of the first carpometacarpal joint.
Radiographs are unnecessary for diagnosis, but they may be useful to rule out osteoarthritis of the first carpometacarpal joint or a scaphoid fracture.
The goals of treatment are to decrease inflammation, prevent adhesion formation, and prevent recurrent tendonitis. Brief periods of icing and use of NSAIDs are helpful initially, and the patient should be placed in a thumb restricting splint (thumb spica splint). If pain continues, a corticosteroid injection should be considered. In most patients, symptoms resolve after a single steroid injection. Steroid injection may be repeated after 4-6 weeks if symptoms are not 50% improved. If no improvement occurs after two injections within the year, a referral for surgical consultation should be obtained.
For many years epicondylitis was thought to be caused by inflammation at the tendon origin; however, recent evidence shows that it is actually due to a breakdown of collagen from aging, microtrauma, or vascular compromise. Although properly termed tendinosis, the condition is referred to by its long-standing name “epicondylitis” throughout this discussion to avoid confusion. Lateral and medial epicondylitis occur at the elbow and are primarily overuse or repetitive stress disorders.
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