A multi-center, single-blinded, randomized, parallel-group, superiority study to compare the efficacy of manipulation under anesthesia versus intra-articular steroid injection in the treatment of patients with frozen shoulder and a diagnosis of rotator cuff injury or tear by MRI: study protocol for a randomized controlled trial

Background Frozen shoulder (FS) is a common condition that can cause severe pain and limited range of motion in the shoulder joint. While intra-articular steroid injection has been shown to be an effective treatment for FS, manipulation under anesthesia (MUA) is an alternative treatment that has gained popularity in recent years. However, there is a lack of evidence regarding the effectiveness of MUA on FS patients with concomitant rotator cuff injury or tear. Though a few studies have shown that MUA is not associated with rotator cuff tears, and will not exacerbate the injury, more high-quality studies with bigger sample sizes are needed. Therefore, the aim of this multi-center, single-blinded, randomized, parallel-group, superiority study is to compare the efficacy of MUA versus intra-articular steroid injection in the treatment of FS patients with a diagnosis of rotator cuff injury or tear by MRI. Methods A parallel, single-blinded, multi-center randomized controlled trial of 320 patients will be conducted at three hospitals of China. Eligible patients with frozen shoulder and rotator cuff injury or tear diagnosed by MRI will be randomly assigned to, in equal proportions, the manipulation under anesthesia group and the intra-articular steroid injection group via a central randomization system, undergoing a corresponding operation on day one and a sequent physical exercise for 14 days. The primary outcome is the comprehensive efficacy evaluation (total effective rate) and the change of Constant-Murley Score. Outcome assessors and data analysts will be blinded, and participants will be asked not to reveal their allocation to assessors. Discussion This study aims to explore the superiority of manipulation under anesthesia in reducing pain and improving shoulder function in frozen shoulder patients accompanied with rotator cuff injury. To provide a scientific basis for the dissemination and application of manipulation under anesthesia, and a better knowledge for the role of MUA in the treatment of frozen shoulder accompanied with rotator cuff injury. Trial registration Chictr.org.cn ChiCTR2200067122 . Registered on 27 December 2022. ChiCTR is a primary registry of the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) network and includes all items from the WHO Trial Registration data set in Trial registration.