Lateral epicondylitis, or tennis elbow, is the most common pain syndrome of the elbow. About 1%-3% of people will experience the condition at some point in their lifetime. It usually occurs between the ages of 35 and 55, and it affects men and women equally.

The condition presents as pain over the lateral epicondyle of the elbow, which could occasionally radiate from the elbow toward the wrist over the extensor musculature. Power grip activities as well as wrist and hand extension can cause painful symptoms.

The condition arises as a result of repetitive use or injury to the common wrist extensor muscle / tendon origin on the lateral epicondyle of the wrist. The pathophysiology is more of a degenerative tendinosis process than an inflammatory process and is due to a failure of tendon repair resulting in angiofibroblastic hyperplasia, vascular hyperplasia, and disorganized collagen, often of the extensor carpi radialis brevis (ECRB). Additionally, there can be accompanied micro-tears of the ECRB, extensor carpi radialis longus (ECRL), and extensor carpi ulnaris (ECU).

Risk factors include anything that involves excessive wrist extension and forearm pronation, such as typing, racket sports like tennis, playing piano or other musical instruments, and performing manual labor (eg, carpentry). It is common in laborers who repetitively grip heavy tools or in workers engaging in repetitive lifting.