Palmar skin injections for trigger finger are un-necessarily cruel
David, M et al's 'clinical update' of trigger finger is a useful review (BMJ 2017;359:j5285). However, whilst a steroid injection is a useful starting point for patients with disturbing symptoms, I find it difficult to agree with the technique recommended. Early in a 30 yr hand surgical career I came to realise that injections into the highly innervated and sensitive palmar skin (certainly with a needle of the calibre recommended by the authors) cause entirely unnecessary pain.
The following technique has served me well and is virtually painless because the web skin between the fingers is relatively poorly innervated:
1) Mark the target spot on palmar skin at the affected A1 pully (about 1 cm distal to the distal palmar crease).
2) Pass a 25G (orange) 2.5 cm needle through the mid-point of the web skin next to the affected finger, parallel and 1 cm deep to the overlying palmar skin, towards the marked spot, until the needle is up to its hub.
3) The tip will now be perfectly positioned adjacent to the flexor sheath. There is NO need to move the tendon.
4) The steroid (best 1 ml triamcinalone 10 mg/ml) will work over a large area during the following 48 hours.
5) There is no benefit at all in the traditional addition of local anaesthetic mixtures to the steroid. How could this help when anaesthetics take some minutes to work whilst injection pain is normally immediate due to volume effects?
This method will virtually guarantee you a happy patient, full of admiration that the proposed injection did not hurt. Moreover, it also avoids the small infection risk associated with the open hub of the needle whilst it being used for what the authors describe colourfully as 'windscreen-wiping'. Finally, it is important to use a fine calibre needle (either 25G or 27G) in order to avoid the theoretical risk of digital nerve bevel injuries when approaching the tendon sheath from laterally.
Competing interests: No competing interests