Adult trigger finger
BMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e5743 (Published 12 October 2012) Cite this as: BMJ 2012;345:e5743
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Henton et al's article on the common condition of trigger finger will be welcomed by many practitioners. However, their technique for first line management, steroid injection at the A1 flexor pulley where the jamming occurs, seems unnecessarily complicated and distressing for the patient. There is a much easier and less involved way.
Henton states that the injection should be into the flexor sheath when actually the idea is to deposit the steroid AT the pulley to soften it and allow passage of the fusiform swelling on the tendon. (It's actually extremely difficult to place any needle tip precisely into the sheath without penetrating the tendon because the space between sheath and tendon is infinitesimal.) Further, he actually proposes TWO painful injections via the highly innervated palmar skin.
A much simpler and more comfortable approach is to access the target (the A1 flexor pulley) via the less sensitive web space skin. I have been using this approach for some 20 years with excellent effect, as follows:
1) Mark the pulley site with a mid-line dot on the palmar skin about 1.5 cms distal to the distal palmar crease.
2) Use a 27 gauge (Sterican) needle to minimise damage to the digital nerves.
3) Ask the patient to spread his/her fingers strongly in order to display the nearest web space.
4) Sterilise the web skin.
5) With palm upwards, insert the needle tip into the centre of the web space about 3/4cm behind (dorsal) to the palmar edge of the web, and advance the needle tip towards the marked point, keeping it parallel to the palmar skin above. The steroid will be deposited precisely at the pulley. (It is better to aim slightly deeper towards the side of the pulley than inject shallow and risk palmar fat atrophy.)
This procedure takes seconds to perform once learned, is often virtually painless, and produces excellent relief from triggering after the same interval as Henton et al's method. Patients who have had previous injections for trigger finger via the palm are usually incredulous.
Competing interests: No competing interests
Re: Adult trigger finger
Henton et al describe an often-used local anaesthetic technique for the injection of trigger digit (1). However, because the method involves injecting through the thick skin of the palm, it causes unnecessary trepidation and pain to the patient, and therefore should not be used at all.
In contrast, pain can be largely avoided by using a dorsal approach to the palmar skin through the soft skin of the middle of the dorsal aspect of an adjacent web space (2,3).
In this technique, the doctor takes hold of the patient’s hand, and with the patient’s fingers relaxed and semi-flexed, the needle is inserted through the skin of the middle of the dorsal aspect of an adjacent web space. The adjacent digits should not be stretched apart as this will tense the skin of the web space, and make the local anaesthetic injection more painful. The needle is then directed towards the subcutaneous tissue overlying the proposed site of the steroid injection (either at the mid-palmar crease or at the MCP crease of the thumb), and the local anaesthetic is injected as the needle is advanced.
In this way, the palmar skin is anaesthetised from within, from its dorsal aspect. Since the needle is directed towards the palmar skin and not sideways towards the flexor sheath, the risk (albeit small) of damage to digital vessels and nerves is minimised.
Since the finer the needle, the less painful will be the local anaesthetic injection, 1ml insulin syringes with 12.7mm 29G (0.33mm) needles are ideal.
Before subsequently injecting the steroid through the palmar skin overlying the affected tendon, time is allowed for the anaesthetic to take effect.
REFERENCES
1. Henton, J, et al. Adult Trigger Finger. BMJ. Vol 345. 10 November 2012. p44-45.
2. Sodera, V. Minor Surgery in Practice. Cambridge University Press. 1994. p87-90.
3. Sodera, V. Steroid Injections. One Small Speck Ltd. Apple iBook Store 2015. p36. http://itunes.apple.com/us/book/id919124271
Competing interests: No competing interests