Understanding Trigger Finger and Its Causes
Trigger finger, medically known as stenosing tenosynovitis, is a condition that causes pain, stiffness, and a sensation of locking or catching when you bend or straighten your finger [1.9.2]. The condition arises from inflammation and thickening of the A1 pulley, a ligament at the base of the finger that forms a tunnel for the flexor tendon [1.9.3, 1.10.1]. This thickening restricts the tendon's movement, causing it to catch or lock [1.9.5]. While the exact cause is often unknown, it's associated with repetitive gripping motions, and certain medical conditions like diabetes, rheumatoid arthritis, and hypothyroidism increase the risk [1.9.3]. Trigger finger is more common in women than men and typically appears between the ages of 40 and 60 [1.9.3, 1.9.2].
How Cortisone Shots Work for Trigger Finger
Corticosteroid injections are a mainstay of non-operative management for trigger finger [1.3.1]. Cortisone is a powerful anti-inflammatory medication that, when injected into the tendon sheath, reduces swelling and inflammation of the A1 pulley and flexor tendon [1.5.2, 1.9.4]. This reduction in inflammation allows the tendon to glide more smoothly through the pulley, alleviating the painful clicking, catching, and locking symptoms [1.9.4]. The procedure is cost-effective, easily performed in an office setting, and less invasive than surgery [1.5.2]. For many patients, a single injection is enough to resolve the issue permanently, while others may require further treatment [1.2.2]. The injection is often mixed with a local anesthetic like lidocaine to provide immediate, short-term pain relief [1.8.1].
How Long Does the Relief from a Cortisone Shot Last?
The duration of relief from a cortisone shot for trigger finger varies widely among individuals. Generally, a successful shot can provide relief for three to six months, and sometimes much longer [1.2.1]. For many patients, the relief can last for several months up to a year or more, and some may never have symptoms again after a single injection [1.2.2, 1.2.5].
However, the longevity of the effect is not guaranteed. One study noted that 45% of patients experienced long-term success after one injection, with most failures occurring within the first two years [1.2.2]. For those who experience a recurrence, a second or even third injection can still be effective, providing long-term relief in about 39% of cases [1.3.3]. The median time to failure for second and third injections was found to be 371 and 407 days, respectively [1.3.3].
Factors Influencing the Duration and Success
Several factors can influence how long a cortisone shot will be effective:
- Severity of the Condition: A high grade of disease (e.g., a finger that is frequently locked) is a strong predictor of symptom recurrence [1.4.1].
- Underlying Medical Conditions: Patients with diabetes mellitus may be more resistant to injection treatment, although studies show they can be managed with equal efficacy to non-diabetics [1.8.1, 1.4.5]. Other conditions like rheumatoid arthritis are also associated with poorer outcomes [1.8.1].
- Duration of Symptoms: Having symptoms for more than six months before treatment is associated with higher rates of recurrence [1.4.4].
- Patient Demographics: Older patient age has been associated with a higher success rate for repeat injections [1.4.2]. One study found that female patients presenting with their first trigger finger had the highest rate of long-term success [1.4.3].
- Previous Injections: A short symptom-free period (less than six months) after a previous injection predicts a higher likelihood of recurrence [1.4.1].
What to Expect After the Injection
Immediately after the shot, the local anesthetic will provide numbness and pain relief for a few hours [1.7.1]. It is common to experience a temporary "cortisone flare," which is an increase in pain and discomfort at the injection site for 24 to 72 hours before the steroid begins to work [1.7.1, 1.2.1]. The anti-inflammatory effects of the cortisone typically start to work within a few days to a week, but it can take up to three or four weeks for the full benefits to be felt [1.2.2, 1.2.5]. One study found the average time to complete pain relief was about 6.6 days, while complete relief from the triggering/locking mechanism took an average of 8.1 days [1.3.1].
Following the injection, it's recommended to rest the hand and avoid heavy or repetitive gripping activities for several days to a few weeks to allow the medication to work and the tendon to heal [1.7.2, 1.7.4].
Comparison of Treatment Options
When conservative measures are needed, several options exist. Cortisone shots are a primary treatment, but splinting and surgery are also common.
| Treatment Option | Pros | Cons | Success Rate |
|---|---|---|---|
| Cortisone Injection | Minimally invasive, quick procedure, cost-effective [1.5.2]. | Potential for pain flare [1.7.3], risk of side effects like skin thinning or tendon weakening (rare) [1.6.3], may not be a permanent solution [1.2.3]. | 40% to 90% long-term resolution from a single shot [1.3.1, 1.4.5]. 50% of patients are better after one shot [1.8.3]. |
| Splinting | Non-invasive, no medication side effects [1.5.2]. Can be done at home [1.5.5]. | May take 6-10 weeks [1.5.2], can be cumbersome, less effective for severe or prolonged symptoms [1.5.2]. | Can be as effective as injections for some patients, with no significant difference in one-year outcomes in some studies [1.5.2]. |
| Surgical Release | Considered the gold standard for a permanent cure [1.5.2]. High success rate [1.2.2]. | Invasive, requires recovery time, higher cost, small risk of infection or nerve damage [1.5.2, 1.9.2]. | Success rates are reported from 90% to 100% [1.9.2, 1.2.2]. |
Conclusion: A Highly Effective but Variable Treatment
A cortisone shot for trigger finger is a highly effective first-line treatment that can provide significant, long-lasting relief for many patients [1.8.1]. The duration of its effect can range from a few months to permanent resolution, influenced by individual factors like disease severity and overall health [1.2.1, 1.2.2]. While many people are cured with one or two injections, it doesn't work for everyone, and about 25% to 30% of patients may ultimately require surgery for a permanent solution [1.8.3]. It is generally recommended not to exceed two or three injections in the same finger due to the risk of weakening the tendon [1.8.2, 1.8.3]. Consulting with a hand specialist is the best way to determine the most appropriate treatment plan for your specific situation. For more information, you can visit the American Society for Surgery of the Hand.
