What is a trigger finger?
A trigger finger (stenosing tenosynovitis) is a painful condition in which one of the fingers gets stuck in one position and then snaps straight. The affected finger may bend or straighten with a snap like a trigger being pulled and released.
A digital flexor injection treats a trigger finger with a corticosteroid to prevent pain and locking.
This condition occurs when swelling narrows the space within the sheath that surrounds the tendon (a fibrous tissue) in the affected finger. In severe cases, the finger may become locked in a bent position.
People whose work or hobbies require repetitive gripping actions are at higher risk of developing a trigger finger. Moreover, the condition is more common in women and people with diabetes.
What is a digital flexor injection?
Corticosteroids can be used to reduce swelling. A digital flexor injection is a conservative treatment for a trigger finger.
A digital flexor injection is usually administered under local anesthesia. The finger to be injected is cleaned with iodine solution or alcohol. Liquid corticosteroids mixed with local anesthetics are injected into the tendon sheath (the membrane that the tendon slides through) at the base of the affected finger or thumb.
The patient experiences momentary pain during the procedure. However, the area becomes numb within some time.
Corticosteroids are thought to work by reducing tendon swelling, allowing the tendon to move freely again. This can sometimes happen within a few days of having the injection, but it usually takes a few weeks.
Is a digital flexor injection effective?
Corticosteroid or digital flexor injections are effective in an estimated 50 to 70% of people with a trigger finger. However, they are generally less effective in people with certain underlying health conditions, such as diabetes and rheumatoid arthritis.
This injection can permanently improve the trigger finger, but in some cases, the problem can return after treatment. Although patients can have a second injection if the first injection effect wears off, it is often less effective than the earlier injection.
How many times can an individual get a steroid injection or digital flexor injection?
A digital flexor injection can be safely administered three times, but overuse of steroid injections can lead to various complications. Doctors typically advise steroid injections no more than three times.
What are the risks of a digital flexor injection?
The risks of corticosteroid injections used for a trigger finger are very rare. Very occasionally, it causes some thinning or color change of the skin at the injection site. There is also a very low risk of infection.
Usually, patients have anesthesia effects such as headache and drowsiness. Potential side effects of a digital flexor injection increase with higher doses and repeated use. Side effects include:
- Damage of the nearby bone
- Cartilage damage
- Joint infection
- Nerve damage
- Temporary facial flushing
- Temporary flare of pain and joint swelling
- Temporary increase in blood sugar
- Tendon weakening or rupture
- Osteoporosis (thinning of the nearby bone)
- Thinning of the skin and soft tissue around the injection site
- Whitening or lightening of the skin around the injection site
What are the common precautions recommended after a digital flexor injection?
Patients are usually advised a 24-hour rest after a digital flexor injection. They are also advised to avoid wetting the site and perform any strenuous activity for several days.
The doctor may advise a few painkillers, antibiotics, and antiinflammatory medications for a few days after a digital flexor injection.