Flexor Tendon Nodule Injection

Trigger finger or trigger thumb

Causes and findings:
• Spontaneous onset: might have osteoarthritis or palpable ganglia in the fingers or hand
• Pvheumatoid arthritis
• Painful clicking and sometimes locking of finger with inability to extend
• A tender nodule can be palpated usually at the base of the finger

Equipment:
Syringe - 1ml
Needle - 25G 0.5 inches (16mm) orange
Kenalog 40 - 10 mg
Lidocaine - 0.25 ml 2%
Total volume - 0.5 ml

Anatomy:
Trigger finger is caused by enlargement of a nodule within the flexor tendon sheath, which then becomes inflamed and painful. It usually occurs at the joint lines where the tendon is tethered down by the ligaments.

Technique:
• Patient places hand palm up
• Identify and mark nodule
• Insert needle perpendicularly into nodule
• Deposit half solution in a bolus into nodule
• Angle needle distally into sheath
• Deposit remaining solution into sheath

Aftercare:
No particular restriction is placed on the patient's activities.

Comments:
This injection is invariably effective. Although the nodule usually remains, it can continue to be asymptomatic indefinitely, but recurrence can be treated with a further injection. Occasionally a slight pop is felt as the needle penetrates the nodule. When the needle is in a tendon, a rubbery resistance is felt.

Alternative approaches:
Some clinicians insert the needle alone first and then ask the patient to flex the finger. If the needle moves, this proves that the correct site has been reached and the syringe may then be attached. As this involves delay and discomfort to the patient, we recommend the method above.