Value of MR arthrography findings for pain relief after glenohumeral corticosteroid injections in the short term.

ABSTRACT

OBJECTIVES: This study was conducted in order to determine the predictive value of MR arthrography findings for pain relief after glenohumeral corticosteroid injection. METHODS: This study prospectively enrolled 212 patients (mean age 51.4 years; range 15-90) who underwent fluoroscopy-guided glenohumeral corticosteroid injection. All patients received MR arthrography of the shoulder less than 3 months prior to the infiltration and returned questionnaires which assessed patients' shoulder pain using the 11-point numeric rating scale (NRS), covering a 1-month follow-up period. MR arthrograms were retrospectively assessed for abnormalities of the rotator cuff, long biceps tendon, glenohumeral bone, cartilage, and labrum as well as for synovitis, bursitis, and signs of adhesive capsulitis. MR arthrography findings were compared to patients' NRS change using the Mann-Whitney U and Kruskal-Wallis tests for univariate analysis and multiple linear regression for multivariate analysis. RESULTS: Pain reduction of ≥ 2 points was considered to represent clinically relevant improvement, which was seen in 71% of patients 1 week and in 74% of patients 1 month after glenohumeral injection. Univariate analysis of MR findings showed that signs of adhesive capsulitis and an intact labrum were associated with significantly higher NRS reductions after 1 month in comparison to patients without these findings (median 4 vs. 3, p = 0.007 and 4 vs. 2, p = 0.003, respectively). Multivariate analysis proved both factors to be independent predictors of improved outcome after 1 month (beta = 0.176, p = 0.039 and beta = 0.212, p = 0.001, respectively). CONCLUSIONS: Glenohumeral corticosteroid injections for pain relief have a high success rate with 74% of patients reporting clinically relevant improvement after 1 month. Signs of adhesive capsulitis and an intact labrum on MR arthrography are independent predictors of a better outcome. KEY POINTS • Seventy-four percent of patients report clinically relevant improvement 1 month after glenohumeral corticosteroid injection. • Signs of adhesive capsulitis and an intact labrum on MR arthrography are independent predictors of a high pain level decrease.