Lateral epicondylitis, commonly known as Tennis Elbow, is a painful condition affecting the elbow tendons. Because this condition involves soft tissue, there is often confusion about the role of bone-focused imaging like X-rays in its diagnosis. The following sections clarify the pathology of this injury and explain why and how X-ray imaging is used in the diagnostic process.
Understanding Lateral Epicondylitis
Lateral epicondylitis is an overuse injury occurring at the lateral epicondyle, the bony prominence on the outer side of the elbow. The condition primarily involves the tendon of the extensor carpi radialis brevis (ECRB) muscle, which originates here. This muscle stabilizes the wrist during activities requiring gripping and is often damaged by repetitive microtrauma. The pathology is a degenerative process, or tendinosis, involving disorganization of collagen fibers and microtears rather than pure inflammation. Repeated strain from activities like gripping, lifting, or repetitive wrist extension causes eccentric overload at the tendon’s origin.
The Diagnostic Purpose of X-rays for Elbow Pain
A healthcare provider frequently orders an X-ray for elbow pain, not to confirm Tennis Elbow, but to perform a differential diagnosis. The primary purpose of this imaging is to rule out other, potentially more serious, causes of pain that mimic the symptoms of lateral epicondylitis. This is a standard step in assessing chronic elbow discomfort. X-rays are highly effective at visualizing dense structures like bone, making them the initial imaging modality for assessing joint integrity.
The radiograph can quickly detect several structural issues that require different treatment plans, including:
- Fractures, such as acute breaks or stress fractures of the humerus, radius, or ulna.
- Joint misalignment, including dislocations or subluxations.
- Degenerative conditions like osteoarthritis, which presents as joint space narrowing or bone spurs.
- Loose bodies within the joint, bone cysts, or rare bone infections and tumors.
By eliminating these bony and structural issues, the physician can more confidently arrive at a diagnosis of a soft tissue problem like Tennis Elbow.
Specific Findings X-rays Can Reveal
While the damaged tendon tissue of Tennis Elbow is invisible on a radiograph, chronic or long-standing cases can sometimes produce secondary findings that are visible. These changes result from the body’s prolonged response to tendon degeneration and repetitive stress at the bone attachment site. The most common finding is calcification, which appears as dense, white deposits in the soft tissue near the lateral epicondyle. These deposits represent calcium within the damaged tendon or surrounding soft tissue, typically seen in advanced stages of the condition. Although their presence does not correlate with the severity of a patient’s pain, they indicate a chronic degenerative process. Other findings include periosteal reaction, a thickening of the outer layer of the bone adjacent to the tendon attachment. In chronic cases, a small bone spur, or osteophyte, may form at the epicondyle where the extensor tendons anchor. The absence of these bony changes on an X-ray does not rule out Tennis Elbow; the clinical diagnosis is still based primarily on symptoms and physical examination.