Trigger finger, also referred to as stenosing tenosynovitis, is a painful condition that affects the fingers or thumb (trigger thumb), causing them to lock or catch when they are bent.
It is due to inflammation of the covering layer of the tendons that control the movement of your fingers and thumbs.
The tendons that control movement of your fingers normally slide smoothly through the sheath that covers them, lubricated by synovial fluid which is a slippery substance produced by the tendon sheath lining (synovium).
Trigger finger normally occurs as the space for the tendon to glide gets smaller. This can be due to the pulley (like a belt loop holding the tendon to the bone) getting narrowed or due to the lining of the sheath becoming thickened. This produces a lump on the tendon which catches and gives the characteristic catch or triggering. Do note that it is possible to have a trigger finger without it catching. In this instance you would find pain and nodularity.
Trigger finger is more common in older people and occurs more frequently in women than in men.
Conditions like diabetes, rheumatoid arthritis and gout can increase the risk of trigger finger due to their tendency to cause thickening of the lining. If you have surgery for carpal tunnel syndrome you are at greater risk of trigger finger in the first six months after the operation.
Symptoms of trigger finger include:
Symptoms may start out mild but can worsen as the condition develops.
An examination is normally used to diagnose trigger finger. The doctor will assess any swelling, stiffness and pain in your finger. If it is locked in a bent position this is an urgent situation as the joint can get secondarily stiff and may not be reversible. You may also have a bump in the palm of your hand.
If the symptoms are mild, you may be able to treat the condition using a splint to immobilise your finger and anti-inflammatories to reduce swelling though the evidence for these treatments is poor. Injections of corticosteroids into the tendon sheath will often resolve the trigger digit.
However, persistent or worsening symptoms may require surgery. This is performed under local anaesthetic . The pulley is released to make space for the lump on the tendon to move without being impeded.
It may take several weeks to recover from surgery as the scar is particularly tender as it’s in the palm.
