Background: Steroid injection is a commonly used conservative treatment for primary frozen shoulder (PFS), but the optimal injection site remains undetermined.
Objectives: We conducted a prospective randomized controlled trial of multisite combined injection (MCI) vs single rotator interval injection (SRI).
Study design: A randomized double-blinded controlled trial.
Setting: Center for Joint Surgery, Department of Orthopaedic Surgery, the Second Affiliated Hospital of Chongqing Medical University.
Methods: Sixty-four patients with PFS were randomly assigned to 2 groups. The experimental group received MCI in the rotator interval, intraarticular, and subacromial bursa; the control group received an SRI. Both groups were injected with one mL of 40 mg triamcinolone acetonide and 4 mL of 2% lidocaine. The injection process was completed under ultrasound guidance. Follow-up points were 4, 8, and 12 weeks postinjection. The outcome measures included the Visual Analog Scale (VAS) score, the American Shoulder and Elbow Surgeons (ASES) score, the Constant-Murley Shoulder (CMS) score, passive range of motion of the shoulder, and patient satisfaction rating.
Results: Thirty patients in the MCI group and 29 patients in the SRI group were included in the data analysis. All the outcomes in the 2 groups were significantly better postinjection than preinjection. The MCI group had a lower VAS score than the SRI group at 4 weeks (3.1 ± 1.2 vs 4.3 ± 1.6) and 8 weeks (2.2 ± 1.2 vs. 3.4 ± 1.2) (P < 0.05). Compared with the SRI group, the MCI group had a significant improvement in flexion and abduction (P < 0.01). Additionally, the ASES and CMS scores in the MCI group were better than those in the SRI group at 4, 8 and 12 weeks (P < 0.01).
Limitations: Limitations include the sample size of this study is small and a that it was conducted at a single-center.
Conclusions: Both MCI and SRI effectively alleviated pain and restored range of motion in patients with PFS. However, the MCI group had obviously lower early pain scores, better flexion and abduction, and better function scores than the SRI group; no additional adverse events were observed.
Keywords: adhesive capsulitis; intraarticular; rotator interval; steroid injection; subacromial bursa; Primary frozen shoulder.