Common Extensor Tendon Injection

Chronic tendinopathy - 'tennis elbow'

Causes and findings:
• Overuse
• Pain at lateral aspect of elbow aggravated by gripping and turning
• Painful: resisted extension of the wrist with elbow extended passive wrist flexion with ulnar deviation

Equipment:
Syringe - 1ml
Needle - 25G 0.5 inches (16mm) orange
Kenalog 40 - 10 mg
Lidocaine - 0.75 ml 2%
Total volume - 1 ml

Anatomy:
Tennis elbow invariably occurs at the teno-osseous origin, or enthesis, of the common extensor tendon at the elbow. The tendon arises from the anterior facet of the lateral epicondyle, which is approximately the size of the little finger nail.

Technique:
• Patient sits with supported elbow at right angle and forearm supinated
• Identify lateral point of epicondyle then move anteriorly onto facet
• Insert needle in line with cubital crease perpendicular to the facet to touch bone
• Pepper solution into tendon enthesis

Aftercare:
The patient rests the elbow for 10 days. Any lifting must be done only with the palm facing upwards so that the flexors rather than the extensors are used;
the causal activity must be avoided. When resisted extension is pain-free, two or three sessions of deep friction with a strong extension manipulation (Mill's manipulation) are given to prevent recurrence. Stretching of the extensors and a strengthening programme is then gradually introduced. If the cause was a
racket sport, the weight, handle-size and stringing of the racket should be checked; as should the technique. Continuous static positions at work should be avoided.

Comments:
This is a very common injectable lesion. Although the teno-osseous junction is the most usual site, the lesion can occur in the body of the tendon, in the
muscle belly and at the origin of the extensor carpi radialis longus. Ignore tender trigger points in the body of the tendon, present in everyone, and place
the needle exactly at the very small site of the lesion. 'Repetitive strain injury' can include true tennis elbow but neural stretching, relaxation techniques, cervicalmobilization and postural advice might be effective if the tendon is clear. One injection usually suffices but, if symptoms recur, a second injection can be given followed by the above routine 10 days later.

Alternative approaches:
Sclerosant injection can be used, or tenotomy may be performed. Depigmentation and/or subcutaneous atrophy can occur in thin females, especially those with dark skins, and they should be informed of this before giving consent. Hydrocortisone should be used if the patient is concerned about these possible side-effects.