Lateral epicondylitis

November 1, 2008

Forty-one-year-old woman presented withlateral elbow stiffness and pain that haveworsened over time. MR imaging shows signal in the common extensor tendon.

CLINICAL HISTORY

Forty-one-year-old woman presented with lateral elbow stiffness and pain that have worsened over time.

FINDINGS

MR imaging shows abnormal morphology and signal in the common extensor tendon consistent with tendinosis and adjacent mild muscle edema in the extensor carpi radialis brevis in coronal T2-weighted (arrow, Figure 1) and axial T2-weighted (arrow, Figure 2) images.

DIAGNOSIS

Lateral epicondylitis with adjacent mild muscle edema.

DIFFERENTIAL DIAGNOSIS

Radial neuropathy, radial neck fracture, capitellum fracture, distal humeral fracture, posterior elbow dislocation.

DISCUSSION

Overuse injuries, also known as cumulative trauma disorders, are very subtle in nature and occur as a result of repetitive microtrauma to bones, joints, and tendons. Lateral epicondylitis is also known as “tennis elbow.”

From 10% to 50% of tennis players develop this condition at some point during their careers. Tennis elbow is one of the most common overuse injuries and is caused by varus stress and tensile load on the elbow leading to microscopic tears of the common extensor group of tendons, which heal poorly.

The backhand stroke in tennis, in which the wrist is maintained in extension and radial deviation, is often responsible for this type of lesion. The typical presentation is an adult patient with insidious onset of lateral elbow pain. Clinically, there is tenderness to palpation over the lateral epicondyle.

Both sexes are affected equally. Affected structures include the tendons of the lateral extensor group of muscles originating at the lateral epicondyle. The tendon of the extensor carpi radialis brevis muscle is frequently involved in lateral epicondylitis. Also reported consistently are the tendons of the extensor digitorum communis and extensor carpi ulnaris muscles.

MRI findings of lateral epicondylitis are variable and include abnormal signal intensity and associated thickening of the tendons of the extensor muscles at their origin in the lateral epicondyle on both T1- and T2- weighted sequences. Normally, the common extensor group of tendons displays low signal intensity in both T1- and T2-weighted MR images. The adjacent lateral collateral ligamentous complex may also be injured in cases of lateral epicondylitis.

A diagnosis of lateral epicondylitis is based on the clinical history and physical examination. Affected patients respond to conservative treatment, which involves physical therapy and/or steroid injection. MRI is generally used in patients who do not respond to conservative treatment. It can help determine the extent of tissue injury and exclude other causes of elbow pain. Surgical treatment is also helpful and is required in advanced cases. Such treatment involves excision of the abnormal tissue and repair of the tendons. MRI is a very sensitive method for detecting these injuries, and familiarity with the MR findings is helpful in making a diagnosis.

Submitted by Archan R. Patel, M.D., musculoskeletal research fellow, and Donald Resnick, M.D., chief of osteoradiology at the VA Medical Center in San Diego, California

BIBLIOGRAPHY

Kijowski R, Tuite M, Sanford M. Magnetic resonance imaging of the elbow. Part II: Abnormalities of the ligaments, tendons and nerves. Skeletal Radiol 2005;34(1):1-18.

Resnick D, Kaang HS, Pretterklieber ML. Internal derangements of joints, vol. 1, pt. V. Amsterdam, the Netherlands: Elsevier, 2006:1174-1177.