Tennis elbow or lateral epicondylitis is the most common injury of the elbow but is often resistant to treatment and prone to recurrence. It occurs as a result of strain of the wrist extensor muscles at their common point of origin, the lateral epicondyle of the humerus. It is most commonly associated with movements that require gripping actions such as holding racket handles or repetitive movements at work (eg. regular use of a screwdriver).
The relative avascularity of the tendon makes it susceptible to microtrauma through repeated gripping actions. Initial inflammatory changes produce a characteristic tendinitis but as the chronic nature of the condition develops the degenerative features of tendinosis are thought to become of greatest significance.
The degenerative condition of the tendon is similar to that seen in chronic overuse conditions of the Achilles tendon in the ankle and the rotator cuff tendons in the shoulder.
There are four possible sites of lesion
• Teno-osseseous junction (enthesis) of the common extensor tendon (mainly extensor carpi radialis brevis) at the anterior facet on the lateral epicondyle of the humerus. This is the most common site
• Origin of extensor carpi radialis longus from the lower third of the lateral supracondylar ridge
• Body of the common tendon as it crosses the head of the radius
• Muscle belly underlying brachioradialis Figure 1: A lateral view of the elbow showing the four possible sites of lesion 34 SportEX
Tennis Elbow Diagnosis
Presentation • The patient complains of gradually increasing pain on the lateral aspect of the elbow and forearm
• The symptoms are provoked by repeated gripping actions together with rotation of the arm
• The patient may complain of muscle weakness accompanied by severe twinges of pain when lifting relatively lightweight objects such as a tea cup
• There is likely to be a full range of passive movement together with negative resisted tests at the elbow joint itself
• Tenderness over the lateral epicondyle
• Pain on resisted wrist extension with the elbow joint in full extension will confirm diagnosis
• Palpation locates the exact site of the lesion but comparison should be made with the asymptomatic side to avoid finding misleading ‘normal’ tenderness