Abductor tendon of the thumb injection is a useful therapeutic procedure for tenosynovitis of extensor pollicis brevis and abductor hallicus longus (de Quervain’s syndrome) usually associated with repetitive trauma disorder. This procedure involves injection of common tendon sheath of the long abductor and short extensor tendons of the thumb.
After informed consent is obtained, the patient is placed in the sitting position with the arm resting on the examination table. The forearm is placed on the ulnar side midway between supination and pronation. The wrist is held in ulnar deviation over a rolled towel, stretching the tendons over the radial styloid. Tendons are palpated for the point of maximal tenderness. The patient is prepared in a standard aseptic fashion over an area large enough to allow palpation of landmarks, and sterile technique is used throughout the procedure. A 1½-in. (3-cm), 23-gauge needle is inserted in a proximal direction, parallel to the tendon at a tangential angle, aiming for the point of maximal tenderness. Once the needle is in the tenosynovium, 0.25 to 0.5 mL of local anesthetic can be injected with a tuberculin syringe without significant resistance. This results in a small sausage-shaped swelling along the length of the tendons. At this point, the syringe containing only local anesthetic is disconnected, and another syringe is used to inject the peritendinous area with a 2-mL mixture of 5 mg of triamcinolone acetonide (or equivalent) and local anesthetic (Fig. 67-44).
FIGURE 67-44. Abductor tendon sheath thumb injection. Approach for abductor tendon sheath of the thumb aspiration and injection.
There should be no significant resistance encountered in the tenosynovium. There will be resistance encountered by the plunger of the syringe if the needle is in the tendon. Steroid injection into the tendon should be avoided.
Injecting directly into the tendon rather than into peritendinous region can result in damage to the abductor tendon of the thumb.