The tendon gets caught in the opening of the pulley and the finger can click painfully as it is straightened. Nodule within the tendon sheath can get stuck in mouth of pulley
What is trigger finger?
Trigger finger is a painful condition in which a finger or thumb clicks or locks as it is bent towards the palm.
Trigger finger happens when there is a thickening at the spot where the tendon passes through a tunnel. Tendons are like ropes that attach from muscle to bone. The finger tendon passes through a tunnel in the palm called the A1 pulley. The tendon can become roughened and swollen. This catches in the tunnel which can be stiff and painful. If the swelling and roughness builds up the tendon can become stuck of locked with the finger in flexion. A tender nodule (bump) can develop at the site of the A1 pulley in the palm.
What causes trigger finger? How did I get it?
Often we can’t identify a particular reason that someone has a trigger finger. Sometimes excessive hard gripping activities puts pressure in the palm and might instigate things. If people have diabetes or rheumatoid arthritis they are more predisposed to developing trigger finger. It usually occurs in people over age 40.
How is trigger finger diagnosed?
Trigger finger is usually diagnosed by a patient’s story of stiffness, pain, and locking of the finger. The physician will be able to confirm this by examining your hand. The finger is stiff to bend and the tendon is very tender in the palm. Imaging tests like X-rays, MRIs, are not helpful and not required.
What are the treatments for trigger finger?
If you find the symptoms (stiffness/locking) minor, some people choose to do nothing. For 1/5th of people a trigger finger might go away on its own without doing anything. In some cases where the pain and swelling are relatively mild, some people will try massaging the area of the nodule/pulley. If this is attempted try rubbing that area side to side for two minutes with some pressure. After massaging stretch the finger back in extension for 30 seconds. This can be tried a couple of times per day.
A study by McKee in 2018 showed that 52% of patients improved without the need for injections or surgery (This means that 48% don”t improve!). Fifty percent of these improved by 8 months; 90% improved of this group improved by one year.
Splints immobilize the joint and allow the pain and tendon swelling to lessen. It’s recommended that the splint be worn 24 hours a day (taking it off to wash/shower) for 6 weeks. After 6 weeks the pain and swelling should be settled and you should be able to slowly start to flex the finger and return normal motion. If after 6 weeks it is still very stiff and painful you should consider an injection. If you experience a partial response to splinting some people find benefit from continuing to splint up to 12 weeks. Some people can’t tolerate these splints during the day because they get in the way. While it might not be as effective, you could try wearing it at night only. For some people this will be helpful enough.
The best splint is one that immobilizes the knuckle called the MCP (metacarpophalangeal) joint. These splints are sometimes a bit awkward for day to day use.
A perhaps slightly less effective splint but one that allows better use of the hand is a finger based splint that prevents flexion of the finger. In Winnipeg these can be obtained through Diamond Athletic Medical supplies.
Injections with cortisteroids (“cortisone”)
Up to two steroid injections at the tendon site cures 70% of all trigger fingers. The steroid medicine softens up the thickened tendon and allows to to move more smoothly. Injections at this site can be painful because the palm is very sensitive. After a couple of days of rest it is recommended to progressively work the tendon (by flexing it) in order to restore the range of motion.
The risks of the injection would primarily include skin infection, skin hypopigmentation (white discoloration of skin at injection site). Allergic reactions to this medicine are highly unlikey. Injuries to the tendon, nerves, or blood vessels are possible but unlikely.
Signs of infection (usually a couple of days after an injection) include redness, swelling, worsening pain. If this occurs you must seek treatment immediately for oral antibiotics.
If the trigger finger is not going away despite a trial of splinting and injections then surgery is usually required. Surgery is generally the cure. Trigger finger does not come back after a successful surgery.
As surgeries go it is pretty simple. It is a day surgery (often in and out within an hour), and often done under local anesthetic.