Factors associated with treatment success following shoulder intra-articular steroid injections.

Abstract

Background: This study aims to investigate the factors which influence the treatment efficacy of intra-articular corticosteroid injections in patients with adhesive capsulitis.

Patients and methods: Between January 2020 and January 2024, a total of 126 patients who received intra-articular steroid injections for adhesive capsulitis were retrospectively analyzed. Pain severity was measured using the Numerical Rating Scale (NRS-11) at four time points: pre-procedure, 1 h post-procedure, three weeks, and three months. Treatment success was defined as a ≥ 50% reduction in the NRS-11 pain scores at three months compared to baseline. Based on this criterion, the patients were categorized into two groups: responders and non-responders. The Central Sensitization Inventory (CSI) was used to evaluate central sensitization and Charlson Comorbidity Index (CCI) was used to assess comorbidity scores. Both groups were compared in terms of demographics, baseline pain scores, range of motion, and magnetic resonance imaging findings.

Results: Of the patients, 40 were male and 86 were female with a mean age of 60.8 ± 11.02 (range, 32 to 83) years. A reduction of ≥ 50% in NRS-11 pain scores was observed in 95.2%, 69.8%, and 67.5% of patients at 1 h, three weeks, and three months post-injection, respectively. There were no significant differences between responders and non-responders in terms of demographic characteristics, baseline pain scores and range of motion, CSI scores, or CCI scores. However, on both univariate and multivariate logistic regression, the presence of acromioclavicular joint degeneration was independently associated with lower odds of treatment success (adjusted odds ratio [OR] = 0.34, 95% confidence interval [CI]: 0.13-0.90, p = 0.030).

Conclusion: Intra-articular corticosteroid injections do not consistently yield favorable outcomes in patients with adhesive capsulitis. Neither central sensitization nor composite comorbidity scores appear to be reliable predictors of treatment failure. However, the presence of additional degenerative changes, such as acromioclavicular joint degeneration, may be associated with poorer outcomes.