Posterior subacromial injections are superior in differentiating a rotator cuff from a biceps pathology: A cadaveric study

Backgroud: the ideal route and accuracy of subacromial injections in shoulder pathologies are often questioned. This study aimed at comparing anterior and posterior injections in terms of subacromial space dye localization and diagnostic accuracy. We hypothesized that posterior injections would prove more accurate. Methods: lidocaine-dye mix was injected posteriorly and anteriorly in five cadaveric shoulders each. Presence of dye was ascertained at dissection. Results: All five posterior injections remained confined to the subacromial space. In all five anteriorly injected shoulders, the dye was seen leaking from the subacromial space into bicipital groove. Conclusions: Varying accuracies of anterior [69–90%] and posterior [56–80%] subacromial injections have been reported. We observed both routes to be equally accurate [100%]. The dye exclusively remained within the subacromial space with posterior injections. This has higher diagnostic value in differentiating subacromial and long head of biceps pathologies. The anterior approach may have a better therapeutic role in combined subacromial and biceps pathologies.