Long-term outcomes following a single corticosteroid injection for trigger finger.

Background: The outcomes of corticosteroid injection for trigger finger are well documented only with short-term follow-up. The purpose of this investigation was to determine the long-term effectiveness of a single injection and to examine predictors of success up to ten years after injection.

Methods: This case series analyzed 366 first-time corticosteroid injections in flexor tendon sheaths from January 2000 to December 2007 with a minimum follow-up duration of five years. Two hundred and forty patients (66%) were female, 161 patients (44%) had multiple trigger fingers, and eighty-eight patients (24%) had diabetes at the time of injection. The primary outcome of treatment failure was defined as subsequent injection or surgical trigger finger release of the affected digit. Medical records were reviewed, and any patients without documented failure or a return office visit in 2012 to 2013 were contacted by telephone regarding symptom recurrence and the need for additional treatment. Kaplan-Meier analyses with log-rank test and Cox regression analysis assessed the effect of baseline patient and disease characteristics on injection success.

Results: Forty-five percent of patients demonstrated long-term treatment success after a single injection. In the final regression model, the interaction of sex and the number of trigger fingers was the single predictor of treatment success. Exploring this association revealed a ten-year success rate of 56% for female patients presenting for the first time with a trigger finger compared with 35% in male patients presenting for the first time with a trigger finger, 39% in female patients with multiple trigger fingers, and 37% in male patients with multiple trigger fingers. Eighty-four percent of treatment failures occurred within the first two years following injection. Patient age, symptom type, and undifferentiated diabetes status were not predictive of treatment success.

Conclusions: Female patients presenting with their first trigger finger have the highest rate of long-term treatment success after a single corticosteroid injection. Patients who continue to experience symptom relief two years after injection are likely to maintain long-term success.