Injection Technique for Tennis Elbow

Indications and Clinical Considerations

Tennis elbow (also known as lateral epicondylitis ) is caused by repetitive microtrauma to the extensor tendons of the forearm. The pathophysiology of tennis elbow is initially caused by microtearing at the origin of the extensor carpi radialis and extensor carpi ulnaris. Secondary inflammation may occur, which can become chronic as a result of continued overuse or misuse of the extensors of the forearm. Coexistent bursitis, arthritis, and gout also may perpetuate the pain and disability of tennis elbow.

Tennis elbow occurs in patients engaged in repetitive activities that include hand grasping, such as politicians shaking hands, or high-torque wrist turning, such as scooping ice cream at an ice cream parlor. Tennis players develop tennis elbow by 2 separate mechanisms: (1) increased pressure grip strain as a result of playing with too heavy a racquet and (2) making backhand shots with a leading shoulder and elbow rather than keeping the shoulder and elbow parallel to the net ( Fig. 61.1 ). Other racquet sport players also are susceptible to the development of tennis elbow.

The pain of tennis elbow is localized to the region of the lateral epicondyle. It is constant and made worse with active contraction of the wrist. Patients note the inability to hold a coffee cup or hammer. Sleep disturbance is common. On physical examination, there is tenderness along the extensor tendons at or just below the lateral epicondyle. Many patients with tennis elbow exhibit a bandlike thickening within the affected extensor tendons. Elbow range of motion is normal. Grip strength on the affected side is diminished. Patients with tennis elbow demonstrate a positive tennis elbow test ( Figs. 61.2 and 61.3 ). The test is performed by stabilizing the patient’s forearm and then having the patient clench his or her fist and actively extend the wrist. The examiner then attempts to force the wrist into flexion. Sudden, severe pain is highly suggestive of tennis elbow.

Radial tunnel syndrome and occasionally C6-C7 radiculopathy can mimic tennis elbow. Radial tunnel syndrome is an entrapment neuropathy that is a result of entrapment of the radial nerve below the elbow. Radial tunnel syndrome can be distinguished from tennis elbow in that in radial tunnel syndrome the maximal tenderness to palpation is distal to the lateral epicondyle over the radial nerve, whereas in tennis elbow the maximal tenderness to palpation is over the lateral epicondyle ( Fig. 61.4 ). Electromyography helps distinguish cervical radiculopathy and radial tunnel syndrome from tennis elbow. Plain radiographs are indicated in all patients with tennis elbow to rule out joint mice and other occult bony disease. On the basis of the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, uric acid, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging of the elbow is indicated if joint instability is suspected. Ultrasound evaluation may also aid in diagnosis in questionable cases ( Fig. 61.5 ). The injection technique described later serves as both a diagnostic and a therapeutic maneuver.