What is it ? (Definition)
Trigger finger is a conflict between flexor tendons and the A1 Pulley.
Pulleys are fibrous ring reinforcing the tendon sheath to maitain the tendons close to the bone. Some (A2 and A4) are important to a normal finger function. A1 is not.
The diameter of a pulley is inextensible and is made to fit perfectly the caliber of tendons going through.
In case of thickenning of the tendons (synovitis), or if there is a cyst on the pulley, tendons cannot slide normally along their sheath, and therefore « trigger and click» in flexion-extension.
In severe cases, the finger can remain locked in flexion and require the assistance of the other hand to unlock it, with a brutal « clicking » sensation.
How to diagnose it? (Presentation)
The diagnostic is usually obvious, based on history and physical examination.
Usually, no additional exam is required prior to treatment.
Occasionally, ultrasound can be useful to demonstrate a cyst or synovitis, and to guide a cortisone injection (see below).
What will happen if you do nothing ? (Natural evolution)
Trigger finger is a benign affection but can be very disabling in daily life.
The functional situation can remain globally unchanged for several months, with punctual episodes of acute crisis.
After a carpal tunnel release, we sometimes observe trigger fingers on the same hand, due to mild superficialisation of the tendon.
For this reason, trigger fingers are thorroughly checked prior to carpal tunnel release.
Spontaneous resolution is rather uncommon.
What are the therapeutical options? (Treatment)
Cortisone injection can be tried in first line. The situation is regularly improved but usually only temporarily.
When it fails, the treatment has to be surgical.
Surgery is performed in ambulatory condition, usually under local anesthesia.
It consists on releasing the compression by cutting the A1 pulley. The flexor tendons are then free to glide without conflict. Sometimes, removal of inflammatory tissues surrounding the tendon is performed additionally (teno synovectomy).
Physiotherapy is of poor interest before surgery, but can be useful afterward to recover full range of motion.
What is the postoperative care ?
A protective dressing is applied for two weeks, then the stitches are removed and massages of the scar are encouraged.
The postoperative care usually requires early active range of motion either self made if well understood, or framed by a physiotherapist or occupational therapist.
Patient’s involvement during this phase is of paramount importance for an optimal final result.
What are the reasonable expectations? (Goals)
– If all goes well :
Return to normal activities is gradually allowed after stitches removal (two weeks).
It usually takes up to 4 to 6 weeks before recovering a normal feeling of the hand, but there is no danger in using it.
– In case of problem :
Occasionally, the surrounding tendons sticks into their sheath and lead to post operative stiffness. This is usually solved by physiotherapy.
Some cases of persistant and unexplained postoperative pain has been described.
As in any operation, the theoretical risk of infection exists but this complication remains rare, thanks to the rigor of prevention protocols.
Other complications may occur but appears to rare to be mentioned here.
Dr Franck ATLAN