Positive outcomes with intra-articular glenohumeral injections are independent of accuracy

Background: Shoulder pain is a common, costly, and recalcitrant affliction. One treatment for shoulder pain is intra-articular injection of corticosteroid. Clinical opinion is that injection guided by palpation is accurate and effective, and there is some evidence to support a positive effect of injection on pain. However, great controversy exists as to the accuracy of injection by palpation, whether or not accuracy is important, and what the effect is of accuracy on pain. Methods: We used a blinded, longitudinal observational design of effectiveness in an effort to determine the accuracy of intra-articular injections and the effect of that accuracy on pain and functional outcomes in patients with various shoulder pathologies. Results: Injection accuracy data were captured on 103 patients. Of the 103 blinded injections, 54 received injections that were identified by fluoroscopy as in the capsule, whereas 49 were identified as outside the capsule; an accuracy rate of 52.4%. In the 4-week follow up, regardless of group assignment or accuracy of the injection, patients improved significantly (P < .01) from pre- to post-injection. Improvement was typically over by 2.5 points in the Numeric Pain Rating Scale (NPRS) categories, over 8 points on the Short-Form McGill Pain Questionnaire (SFMPQ), and over by 13 points on the Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH). Discussion: Our accuracy rate was within the range reported in the literature. Improvements in all subjects with regard to pain and self-reported function occurred even in light of a wide variance in subject duration of symptoms, multiple injectors with varied training, a blinded approach to injection, and multiple injection approaches. Conclusions: The accuracy of the injection does not appear to depend on the experience of the physician and may be irrelevant in treating shoulder pain of multiple origins. Level of evidence: Level II, Prospective Cohort Study, Treatment Study. (C) 2010 Journal of Shoulder and Elbow Surgery Board of Trustees.