Definition

Epicondylitis is a general term used to describe inflammation, pain, or tenderness in the region of the medial or lateral epicondyle of the humerus. The actual nidus of pain and pathologic change has been debated. Lateral epicondylitis implies an inflammatory lesion with degeneration at the tendinous origin of the extensor muscles (the lateral epicondyle of the humerus). The tendon of the extensor carpi radialis brevis muscle is primarily affected. Other muscles that can contribute to the condition are the extensor carpi radialis longus and the extensor digitorum communis.

Although the term epicondylitis implies an inflammatory process, inflammatory cells are not identified histologically. Instead, the condition may be secondary to failure of the musculotendinous attachment with resultant fibroplasia [2], termed tendinosis. Other postulated primary lesions include angiofibroblastic tendinosis, periostitis, and enthesitis [3]. Overall, the focus of injury appears to be the common extensor tendon origin. Symptoms may be related to failure of the repair process [4].

Repetitive stress has been implicated as a factor in this condition [5]. Overuse from a tennis backhand (especially a one-handed backhand with poor technique) can frequently lead to lateral epicondylitis (hence, the term tennis elbow is frequently used synonymously with lateral epicondylitis, regardless of its etiology). Repetitive computer use (especially with a mouse) as well as golf, swimming, and baseball can cause or exacerbate epicondylitis.

Symptoms

Patients usually report pain in the area just distal to the lateral epicondyle. The patient may complain of pain radiating proximally or distally. Patients may also complain of pain with wrist or hand movement, such as gripping a doorknob, carrying a briefcase, or shaking hands. Patients occasionally report swelling as well.

Physical Examination

On examination, the hallmark of epicondylitis is tenderness over the extensor muscle origin. The common origin of the extensor muscles can be located one fingerbreadth below the lateral epicondyle. With lateral epicondylitis, pain is increased with resisted wrist extension, especially with the elbow extended, the forearm pronated, the wrist radially deviated, and the hand in a fist. The middle finger test can also be used to assess for lateral epicondylitis. Here, the proximal interphalangeal joint of the long finger is resisted in extension, and pain is elicited over the lateral epicondyle. Swelling is occasionally present. In cases of recalcitrant lateral epicondylitis, the diagnosis of radial nerve entrapment should be considered. The radial nerve can become entrapped just distal to the lateral epicondyle where the nerve pierces the intermuscular septum (between the brachialis and brachioradialis muscles). There may be localized tenderness along the course of the radial nerve around the radial head. Motor and sensory findings are usually absent.

Functional Limitations

The patient may complain of an inability to lift or to carry objects on the affected side secondary to increased pain. Typing, using a computer mouse, or working on a keyboard may re-create the pain. Even handshaking or squeezing may be painful in lateral epicondylitis. Athletic activities may cause pain, especially with an acute increase in repetition, poor technique, and equipment changes (frequently with a new racket or stringing).

Diagnostic Studies

The diagnosis is usually made on clinical grounds. Magnetic resonance imaging, which is particularly useful for soft tissue definition, can be used to assess for tendinitis, tendinosis, degeneration, partial tears or complete tears, and detachment of the common extensor tendons at the lateral epicondyle [6]. Magnetic resonance imaging is rarely needed, however, except in recalcitrant epicondylitis, and it will not alter the treatment significantly in the early stages. The lateral collateral ligament complexes can be evaluated for tears as well as for chronic degeneration and scarring. Ultrasonography has been used to diagnose lateral epicondylitis [7]. Arthrography may be beneficial if capsular defects and associated ligament injuries are suspected. Barring evidence of trauma, early radiographs are of little help in this condition but may be useful in cases of resistant tendinitis and to rule out occult fractures, arthritis, and an osteochondral loose body.