A flare-up of trigger finger is often caused by DIY activities such as using screwdrivers or pistol-grip power tools requiring repetitive grasping actions with pressure into the palm.
The condition involves the clicking, locking or snapping of a finger at the metacarpophalangeal joint. In adults, the middle and ring finger are most commonly affected. The peak incidence is in those aged between 55 and 60.
Patients with diabetes, rheumatoid arthritis, gout or hypothyroidism are more likely to develop trigger finger.
A congenital form of the condition is occasionally seen in children's thumbs, and patients with this condition should be referred to a specialist for surgical correction.
In adults, the problem develops where the finger flexor tendon runs into its sheath. The sheath becomes irritated, the tendon cannot slide smoothly and itself becomes swollen.
A vicious circle is generated with constriction aggravating the swelling and vice versa. The enlarged tendon may be palpable as a nodule in the palm at the distal palmar crease.
The first symptom is often discomfort at the affected finger base, with uneven and painful finger movement. Patients then find that, when they relax a fist, the affected finger remains flexed and can be straightened only by passive movement, with a click. In severe cases, the finger is locked in the bent position.
The differential diagnoses include suppurative tenosynovitis (which needs urgent referral to a hand surgeon) or a Dupuytren's contracture.
The tendon sheath is injected with steroid to reduce swelling. This is successful in about three quarters of cases. A maximum of three injections is advised. Care should be taken not to inject the tendon itself.
Warn patients to report signs of infection or excessive bleeding after injection. Patients with diabetes may notice transient elevation in blood sugars.
Although nerve injury is uncommon, the finger may be numb for a few hours after the injection. Patients should avoid excessive stress on the finger for the next few weeks.
Surgery is indicated if three steroid injections fail to produce improvement.
After the operation, the patient is advised to take anti-inflammatories and elevate the hand for a few days to minimise swelling. Active movement is encouraged on the day of surgery.
Nerve damage is rare but may require operative repair.
Patients should be aware that activities using the affected hand may be restricted for four to six weeks. Recurrence in the same finger is rare, but triggering may subsequently occur in other fingers.
- Dr Lackey is a GP in Killingworth, Tyne and Wear and Mr Sutton is a consultant orthopaedic surgeon in Northumberland
- Trigger finger involves the clicking, locking or snapping of a finger at the metacarpophalangeal joint.
- Multiple trigger fingers may suggest an underlying cause, such as diabetes.
- If three steroid injections are unsuccessful, surgical treatment is indicated.