INTRODUCTION

Although the number of diseases that affect the elbow with any degree of frequency is small, examining the joint often provides clues to diagnosis of specific neuromuscular disease. Pain is the symptom that focuses attention on this joint and prompts the patient to visit the physician. Although it usually reflects a localized process at the elbow, the pain may be referred from the hand and wrist or from the shoulder and neck. Most abnormal actions of the elbow can be compensated by the shoulder; therefore, even moderate compromises of motion, provided they are painless, do not result in disability. Subtle flexion contractures may develop over years without the patient even being aware of the changes or range-of-motion losses. In contrast, significant pain at the elbow incapacitates the entire arm. Sleeves of clothing often cover the elbows; thus, swellings and deformities become cosmetically important only when they are exaggerated. The examiner should note whether swelling is intracapsular or extracapsular, intramuscular or intermuscular. The earliest sign of joint effusion is induration of the capsule around the olecranon or epicondyles. In the flexed position, the hollows of the indurated synovium are totally filled.

When the elbow is extended, the epicondyles and the tip of the olecranon should be at the same level. In normal elbow configuration, when a line is drawn between the epicondyles, the olecranon should bisect and be on the center of the line. When the normal elbow is flexed to an angle of 90 degrees, the tip of the olecranon should be directly below to the line joining the epicondyles. If a line from the olecranon is drawn to each epicondyle, the three prominences and line should form an isosceles triangle.

TABLE 5-2 ELBOW JOINT CROSS-REFERENCE TABLE BY SYNDROME

If the triangle is normal but abnormal in relation to the shaft of the humerus, the patient may have a supracondylar fracture in which the three bony landmarks are displaced posteriorly.

The examination of the elbow must be preceded by a precise history to allow emphasis to be placed on particular areas. Complaints usually consist of pain, loss of movement, weakness, clicking, or locking.

The patient may complain of sharply localized pain, typical of an extraarticular abnormality, deep joint pain, or the poorly localized pain of ulnar neuropathy with or without typical paresthesia extending to the hand. The functional interplay among the elbow, shoulder, and wrist means that examination of all of these joints may be necessary (Table 5-3). Referred pain in the elbow, especially from the neck or shoulder, is usually diffuse. Examination must include comparison of right and left arms.

TABLE 5-3 FUNCTIONAL ARC MEASUREMENTS FOR SELECTED ACTIVITIES OF DAILY LIVING

From Kelley WN, et al: Textbook of rheumatology, ed 5, Philadelphia, 1997, WB Saunders.

Pain of lateral elbow origin is usually diagnosed as radiohumeral bursitis, epicondylitis, or tennis elbow. All of these problems involve the origin of the wrist extensors (tendinopathy) or, occasionally, radial nerve impingement by musculotendinous structures crossing the elbow joint.

A similar problem may occur on the medial elbow epicondyle because all of the wrist flexors and pronators originate from the medial epicondyle. Affected individuals use flexor-pronator muscle groups repetitively, isometrically or isokinetically. This circumstance is unusual because forceful wrist flexor power is seldom used. Most of powerful hand grasping is accomplished in the dorsiflexed wrist position.

Intraarticular abnormalities such as osteochondritis dissecans of the capitellum result in lateral elbow pain.

Osteochondritis dissecans of the elbow is an idiopathic disorder that affects the capitellum of the humerus, with ensuing avascular necrosis. It is usually seen in the dominant arm of adolescent boys, especially those involved in throwing sports. Panner disease is a condition of unclear origin in which osteochondrosis of the capitellum occurs. It is seen most often in young boys who complain of tenderness and swelling over the lateral aspect of the elbow with limited extension. Direct trauma or inadequate circulation through the elbow joint has been associated with osteochondritis of the capitellum.

An extremely minor fracture of the radial head (chisel fracture) may cause pain that can be confused with tennis elbow. An injury occurring in children and adolescents in whom the medial epicondyle is inflamed with partial separation of the apophysis is little leaguer’s elbow.

Boxer’s elbow (also called hyperextension overload syndrome or olecranon impingement syndrome) is caused by repetitive valgus extension of the elbow in the boxer’s jab or in sports involving throwing. Elbow joint hyperextension injuries usually result from falling on an outstretched arm. The elbow is extended and the forearm supinated.

Pain in the elbow, particularly extending along the entire arm, in the absence of objective findings at the joint suggests psychogenic origins. Other diseases referring pain to the elbow include myocardial infarction, cervical root lesions, thoracic outlet syndromes, and subdeltoid bursitis. Psychogenic origins are further supported with a history of neurosis, strange behavior, or a bizarre and inconsistent complaint history; diagnostic imaging and laboratory tests are as unimpressive as the physical findings. Carpal tunnel syndrome may cause retrograde radiation of pain to the elbow.

Elbow joint complaints usually consist of pain, loss of movement, weakness, clicking, or locking. The patient may complain of sharply localized pain (typical of an extraarticular abnormality), deep joint pain, or poorly localized pain of ulnar neuropathy with or without typical paresthesias extending to the hand. The functional interplay among the elbow, shoulder, and wrist means that examination of all these joints is necessary. Referred pain in the elbow, especially from the neck or shoulder, is usually diffuse (Table 5-4).

TABLE 5-4 UPPER EXTREMITY PERIARTICULAR SYNDROME DIFFERENTIAL DIAGNOSTIC LIST