Determinants of therapeutic success of corticoids injections in trigger finger syndrome.

Background and Objective: Trigger finger is a frequent complaint in which corticosteroid infiltrations play a relevant therapeutic role in intermediate degrees of severity when conservative treatment has not worked. However, there are no criteria to select which patients will benefit most from this procedure. The present study aimed to identify the factors leading to the therapeutic success of corticosteroid infiltration in these patients.
Materials and Methods: We designed a prospective longitudinal study based on routine clinical practice with adult patients with a clinical diagnosis of trigger finger grade II or III on the Quinnell scale, who underwent an infiltration of 20 mg of triamcinolone acetate. The outcome variables were to achieve a Quinnell grade I or reduce the severity of the symptoms by at least one category two months after the procedure. To identify the determinants of complete or partial therapeutic success, binary logistic regression predictive modelling was performed using those variables that had a satisfactory univariate correlation.
Results: 74 patients were included over three years, 42 of whom (61.8%) were classified as Quinnell grade III. After infiltration, 22 (32.4%) achieved complete resolution and 50 (73.5%) partial resolution. The variables tendon thickening (HR 10.72; 95%CI 2.88-39.93; P < .001) and progression time (HR 1.23; 95%CI 1.02-1.49; P = .027) proved to be predictors of therapeutic success in complete resolution. For the modelling for partial resolution, the same variables proved to be determining predictors (HR 5.57; 95%CI 1.38-22.41; P = .016 and HR 1.18; 95%CI .99-1.41; P = .051, respectively). Pulley thickening did not demonstrate predictive ability in either model.
Discussion and Conclusions: Our results indicate that the demonstration of finger flexor apparatus thickening is the main determining factor for the success of corticosteroid infiltrations in this pathology. This is in agreement with the histological findings of specimens obtained from both tenosynovial and pulley tissue. In the former, in addition to an infiltrate of inflammatory characteristics, the presence of chondrocytoid cells producing hyaluronic acid is demonstrated. Although the therapeutic success of infiltrations in previous studies reaches 70%, the recurrence rate is similar after 12 months. The selection of patients with tendon thickening ensures therapeutic success in the short term, could reduce recurrence in the long term, and avoid delay in release surgery.
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