Most often, tendon injury is caused by chronic overuse resulting in degenerative changes.^2,³ The classic inflammatory signs of pain, warmth, erythema, and swelling may sometimes be experienced acutely, although tendinitis is no longer thought to be an inflammatory disorder.⁴ Bursae may become inflamed for many reasons: chronic friction, trauma, crystal deposition, infection, and systemic diseases (rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, tuberculosis, and gout). Because tendons frequently cross over bursae, it is not uncommon for bursitis to be secondary to overlying tendonitis (e.g., supraspinatus tendinitis, subacromial bursitis).

Tendonitis

The signs and symptoms of tendinitis can be quite variable. Pain is the most common complaint of patients with joint problems seen in the ED. Particular attention should be paid to the location of the pain; it can be articular (within the joint capsule), as in septic arthritis, or periarticular (outside the joint capsule), as in tendinitis or bursitis (Table 86.1).

Table 86.1 Clinical Features of Articular versus Periarticular Joint Pain

CLINICAL FEATURE	ARTICULAR	PERIARTICULAR
Associated conditions	Septic or other arthropathies	Tendinitis and bursitis
Range of motion	Decreased	Preserved
Pain	With passive and active motion	Only with certain active movements
Fever	Yes	No*
Trauma	Fractures	Repetitive use or stress
Risk factors	Rheumatoid and psoriatic arthritis, osteoarthritis, crystal arthropathy	Corticosteroid or fluoroquinolone use, connective tissue disease
Association with rest	Morning stiffness improves throughout the day	Night pain prevents sleep

^* Exceptions are septic bursitis and suppurative tenosynovitis.

Bursitis

Inflammation of a bursa may be infectious or traumatic, degenerative, or due to underlying systemic disease.⁵ Risk factors for the development of bursitis are acute trauma, repetitive injury to the painful area, infections, tuberculosis, gout, pseudogout, uremia, and rheumatoid arthritis. The diagnosis is made clinically based on tenderness at a bursal site, swelling of a superficial bursa, and localized pain with motion and at rest. Regional loss of active motion may occur as a result of swelling; however, range of motion should not be affected in patients with aseptic bursitis (see the Red Flags box on tendinopathy and bursitis).

Red Flags

Tendinopathy and Bursitis

Any joint effusion with systemic symptoms is septic arthritis until proved otherwise.

Any injury in a patient with a history of trauma is considered a fracture until proved otherwise.

Pain with passive motion indicates joint involvement; further investigation for an inflammatory or infectious cause is needed.

A history of steroid injection into a large tendon greatly increases the risk for rupture.

Steroid injections or systemic steroids increase the risk for infection.

Fluoroquinolone use increases the risk for tendonitis and tendon rupture.

Presenting Signs and Symptoms

Shoulder

Supraspinatus Tendinitis/Impingement Syndrome

Because of its complex structure and extensive range of motion, the shoulder is a joint predisposed to overuse injuries. The muscles of the rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) and the glenohumeral ligaments serve to stabilize the joint. Impingement of these tendons occurs because of their position between the humeral head and acromion, which predisposes to chronic tendinosis ^6,⁷ (Table 86.2). Impingement syndrome is the number one cause of shoulder pain. It occurs in three progressive stages that worsen over time. Testing and staging of impingement syndrome are reviewed in Table 86.3.

Table 86.2 Shoulder Tendinopathies

Table 86.3 Impingement Syndrome of the Supraspinatus Tendon

In addition to the classic tests for impingement, the examiner should isolate and test individual muscles of the rotator cuff. The empty beer can position tests the supraspinatus by applying downward resistance to an arm in 90 degrees of abduction and 30 degrees of flexion with the thumb pointed downward. Applying resistance to external rotation when the elbow is against the patient’s body and bent at 90 degrees tests the infraspinatus and teres minor. The subscapularis is tested with the arm in the same position and applying resistance to internal rotation.

Subacromial Bursitis

The subacromial bursa lies under the acromion and coracoacromial ligament, to which it is attached. This bursa separates the ligament from the supraspinatus muscle and rotator cuff. Subacromial bursitis is thus thought to be an extension of supraspinatus tendinitis and typically follows this disorder’s stages of impingement. Pain and tenderness are localized to the lateral aspect of the shoulder, and signs of impingement are noted on physical examination (see Table 86.3).

Elbow

Lateral and Medial Epicondylitis

The lateral and medial epicondyles are commonly injured as a result of repetitive use (Table 86.4). Pain often begins as a dull ache that increases with the inciting activity. Approximately 50% of tennis players will experience lateral epicondylitis, although less than 5% of those with the syndrome play tennis. Radiographs may be helpful in atypical or prolonged cases to exclude rare pathologic conditions such as tumors.⁸

Table 86.4 Elbow Tendinopathies