Trigger fingers
Trigger finger is a descriptive term indicating the flexor tendons (that bend the fingers) catching as they go in and out of the fibro-osseous tendon sheath.
The opening to the sheath (A1 pulley) in the distal palm is too tight. The tendon can become swollen and inflamed (tenosynovitis) and a nodule forms causing pain and in turn the sheath becomes thickened and fibrotic.
When the blockage becomes more severe the finger locks; usually it is stuck in flexion and needs to be painfully pulled into extension. Once the thickened tendon is running in the sheath it usually moves quite freely.
Incidence
Trigger fingers are very common in adults, particularly in middle aged women and diabetics.
Other predisposing factors can include
Presentation
Any finger can lock or snap but most common is the ring and middle
Treatment
Recovery
The operation has a high success rate (close to 100%) and serious problems are rare but can occur
The opening to the sheath (A1 pulley) in the distal palm is too tight. The tendon can become swollen and inflamed (tenosynovitis) and a nodule forms causing pain and in turn the sheath becomes thickened and fibrotic.
When the blockage becomes more severe the finger locks; usually it is stuck in flexion and needs to be painfully pulled into extension. Once the thickened tendon is running in the sheath it usually moves quite freely.
Incidence
Trigger fingers are very common in adults, particularly in middle aged women and diabetics.
Other predisposing factors can include
- Collagen disorders
- Secondary to sharp trauma (partial laceration of flexor tendon)
- Rheumatoid Arthritis (causes more extensive tenosynovitis)
- Gout
Presentation
Any finger can lock or snap but most common is the ring and middle
- Finger locks with flexion, remains flexed when trying to straighten, then snaps into extension
- Tender nodule over the A1 pulley which is the entrance to the tendon sheath(just proximal to the distal palmar crease)
- Many people complain of pain radiating to the proximal interphalangeal (PIP) joint of the finger and this joint can become stiff
Treatment
- Steroid injection at the entrance to tendon sheath
- Most people get at least temporary relief
- Can be curative if early presentation and symptoms mild
- Overall, the literature tells us 30% of injected triggers will not require an operation. (40% with 2 injections)
- Surgical release
- Performed under local anaesthetic and sedation
- Small incision in the distal palmar crease region
- The A1 pulley/ tendon sheath is longitudinally incised until triggering is relieved
- this effectively "vents" the sheath to allow the tendon to run freely
- The sheath is explored and any inflamed synovium removed (tenosynovectomy)
- In rheumatoid arthritis the pulley system is preserved (synovectomy performed through an extensile approach)
Recovery
- The triggering/ locking is usually relieved immediately but soreness often persists (from tendon inflammation and scar soreness) for up to 3 months.
- A bulky dressing is used initially but immediate hand use is encouraged and the dressing can be removed and hands washed from day 5 post op.
- ice packs (gel pack - not wet) are helpful to relieve soreness and swelling
- The sutures are removed between 7 to 10 days (usually first post operative visit).
The operation has a high success rate (close to 100%) and serious problems are rare but can occur
- wound problems are uncommon but some wound soreness is quite common (it is a sensitive area)
- persistent triggering is very rare and may be due to other unrecognised pathology. It may require further imaging and surgery.
- the PIP joint (first finger joint) can remain/ become stiff, particularly if there is a severe or chronic preop trigger and/ or arthritis in the joint
- deep infection (to the tendon sheath) is rare (<0.5%) but requires surgical washout and can lead to a poor result (stiffness)
- digital nerve injuries are very rare (thumb nerves are at slightly higher risk)
- pain syndromes (CRPS) are also rare
