Tennis Elbow: Understanding the Condition, Ultrasound Diagnosis, and Other Methods

Can you see tennis elbow on ultrasound?

Yes, ultrasound is a highly effective diagnostic tool for visualizing the structural changes associated with tennis elbow (lateral epicondylitis), providing real-time imaging of the affected tendons and surrounding tissues.

Understanding Tennis Elbow (Lateral Epicondylitis)

Tennis elbow, clinically known as lateral epicondylitis, is a common overuse injury characterized by pain on the outer side of the elbow. Despite its name, it affects a wide range of individuals, not just tennis players, often stemming from repetitive wrist extension and forearm rotation.

Anatomy Involved: The condition primarily affects the extensor carpi radialis brevis (ECRB) tendon, one of the muscles responsible for extending the wrist and fingers. This tendon, along with others, originates from a bony prominence on the outer part of the elbow called the lateral epicondyle. Overuse leads to microscopic tears and degenerative changes (tendinosis) in these tendons, particularly at their attachment point to the bone.

Causes and Mechanism: Repeated gripping, twisting, and wrist extension movements can overload the extensor tendons, leading to:

• Microtrauma: Small tears within the tendon fibers.
• Degeneration: A breakdown of the collagen matrix within the tendon, rather than true inflammation (which is why "tendinosis" is often preferred over "tendinitis").
• Failed Healing Response: The body's attempt to repair the damage is often insufficient, leading to chronic pain and dysfunction.

Symptoms:

• Pain and tenderness on the outer part of the elbow, often radiating down the forearm.
• Pain aggravated by gripping, lifting, carrying, or extending the wrist.
• Weakness in grip strength.
• Morning stiffness.

The Role of Ultrasound in Diagnosing Tennis Elbow

Musculoskeletal ultrasound (MSK US) has become an invaluable tool in the diagnosis and management of tennis elbow due to its non-invasive nature, real-time capabilities, and ability to visualize soft tissue structures with high resolution.

What Ultrasound Can Show: When examining the lateral epicondyle and common extensor origin, ultrasound can reveal several characteristic findings indicative of tennis elbow:

• Tendon Thickening: The affected tendons, particularly the ECRB, may appear thickened due to degenerative changes and swelling.
• Hypoechogenicity: Areas within the tendon may appear darker than normal (hypoechoic) on the ultrasound image, indicating structural disorganization or fluid accumulation within the tendon.
• Calcifications: Small deposits of calcium may be present within the damaged tendon.
• Cortical Irregularities: The bone surface of the lateral epicondyle may show irregularities or spurs where the tendon attaches, indicating chronic traction or degenerative changes.
• Neovascularization: The presence of new, abnormal blood vessels within the tendon, often associated with chronic pain states. This can be visualized using Doppler ultrasound.
• Tendon Tears: While less common in typical tennis elbow, partial or full-thickness tears of the extensor tendons can be identified.

Advantages of Ultrasound:

• Non-invasive and Safe: Uses sound waves, no ionizing radiation.
• Real-time and Dynamic Assessment: Allows for visualization of the tendon during movement (e.g., wrist extension), which can reveal pain provocation or impingement not visible at rest.
• Cost-Effective and Accessible: Generally less expensive and more readily available than MRI.
• Guidance for Procedures: Can be used to guide injections (e.g., corticosteroid, PRP) precisely to the affected area.
• Comparison: Allows for comparison with the asymptomatic elbow.

Limitations of Ultrasound: While highly effective, ultrasound does have some limitations:

• Operator-Dependent: The quality of the examination heavily relies on the skill and experience of the sonographer and interpreting physician.
• Limited Field of View: Can be challenging to visualize large areas or deep structures comprehensively in a single view.
• Gas and Bone Shadowing: Air (e.g., in the gut) and bone can obscure deeper structures.
• May Miss Subtle Changes: Very subtle tendinopathic changes might be missed, especially if they are deep within the tendon or if the scan is not performed by an expert.

What to Expect During an Ultrasound Examination

During the examination, you will typically sit or lie down, and a gel will be applied to your elbow. A small transducer (probe) will be moved over the outer aspect of your elbow and forearm. You may be asked to move your wrist or fingers to assess the tendons in different positions, allowing the sonographer to observe tendon movement and identify areas of pain. The procedure is painless and usually takes about 15-30 minutes.

Other Diagnostic Methods

While ultrasound is excellent for visualizing soft tissue, it's part of a broader diagnostic process.

• Clinical Examination: This is always the first step. A thorough physical assessment by a healthcare professional involves palpation of the lateral epicondyle, specific provocative tests (e.g., Cozen's test, Maudsley's test) to reproduce pain, and assessment of grip strength and range of motion.
• X-rays: Typically used to rule out other bone-related issues, such as fractures, arthritis, or calcifications that are large enough to be seen on plain film. X-rays do not show soft tissue damage like tendinopathy.
• Magnetic Resonance Imaging (MRI): MRI provides highly detailed images of soft tissues, including tendons, muscles, ligaments, and cartilage. It is often used when the diagnosis is unclear, if there are concerns about other structures (e.g., nerve impingement, intra-articular pathology), or for pre-surgical planning. While more expensive and time-consuming, MRI offers a broader view of the entire joint complex.

Conclusion: The Diagnostic Value

In summary, ultrasound is a powerful and primary imaging modality for diagnosing tennis elbow. It can clearly visualize the characteristic structural changes in the extensor tendons, helping to confirm the diagnosis, assess the severity of the condition, and guide treatment strategies. However, it is crucial to remember that imaging findings should always be correlated with the patient's clinical symptoms and physical examination. A comprehensive approach, combining clinical assessment with appropriate imaging, ensures an accurate diagnosis and an effective treatment plan for individuals suffering from tennis elbow.