What is lateral epicondylitis (tennis elbow)?

What is Tennis Elbow (Lateral Epicondylitis)?

Tennis elbow is a degenerative tendon disorder affecting the common extensor origin at the lateral epicondyle of the elbow, caused by repetitive wrist extension and forearm movements that lead to microtrauma and tendon breakdown. 1, 2

Pathophysiology

• The condition represents a tendinopathy (not tendinitis), meaning it involves degenerative changes rather than acute inflammation in the extensor carpi radialis brevis tendon and other wrist extensors that originate at the lateral epicondyle 2, 3

• Repetitive microtrauma occurs when forceful gripping is combined with wrist extension, creating excessive stress at the common extensor origin 4

• The underlying pathology involves abnormal tendon tissue with areas of scarring and fibrosis rather than inflammatory cells 1

Epidemiology and Risk Factors

• Lateral epicondylitis is 7-10 times more common than medial epicondylitis and affects men and women equally 1, 5

• The condition primarily affects adults aged 40 and older, with the dominant arm involved 75% of the time 1, 4, 5

• Despite its nickname "tennis elbow," the condition frequently occurs in occupational settings requiring repetitive wrist flexion and extension, not just racquet sports 1, 6

Causative Movements and Activities

• Repetitive wrist extension against resistance is the primary culprit, particularly in racquet sports and manual labor 4

• Occupations demanding repetitive forearm pronation and supination combined with wrist extension place workers at high risk 4

• Modern activities like computer mouse use and typing with sustained wrist extension contribute to development 4

• Activities requiring stabilizing the wrist in extension while the elbow is straight create maximum stress on the lateral epicondyle 4

Clinical Presentation

• Patients experience lateral elbow pain that worsens with activities requiring wrist extension and weakened grip strength 2

• Pain is exacerbated by common daily activities like shaking hands or opening doors 4

• The diagnosis is made clinically through history and physical examination, with imaging reserved for inconclusive cases or persistent symptoms 5

Natural History

• Lateral epicondylitis is typically a self-limiting condition, though symptoms may persist or recur despite treatment 6, 3

• Chronic, recalcitrant symptoms typically occur in older patients, while acute onset is more common in young athletes 7