IntroductionPeriarthritis of the shoulder, or frozen shoulder (FS), is a common, painful, and disabling condition with varied treatment strategies. Intra-articular (IA) corticosteroid (CS) injections are a popular treatment option, but their efficacy is often temporary. Platelet-rich plasma (PRP) has emerged as an alternative therapy for adhesive capsulitis, but the literature on its effectiveness is limited. This study aimed to compare the efficacy of IA PRP and CS injections in managing FS.MethodsIn this prospective, randomized study, 68 patients who met the inclusion criteria were enrolled and randomized using a computer-generated table into two groups: Group 1 (IA PRP) received 4 ml PRP, and Group 2 (IA CS) received 2 ml (80 mg) of methylprednisolone acetate mixed with 2 ml normal saline (for a total of 4 ml) as a CS injection in the IA area of the shoulder. Outcome measures included pain; shoulder range of motion (ROM); the condensed version of the disabling conditions of the arm, shoulder, and hand (QuickDASH) score; and the shoulder pain and disability index (SPADI) score. Participants were monitored via follow-up for 24 weeks, with pain and function assessed at each evaluation using the visual analog scale (VAS) score, the SPADI score, and the QuickDASH score.ResultsThe IA PRP injections demonstrated better long-term outcomes than the IA CS injections, significantly improving pain, shoulder ROM, and daily activity performance. After 24 weeks, the mean VAS score in the PRP and methylprednisolone acetate groups was 1.00 (1.0 to 1.0) and 2.00 (2.0 to 2.0), respectively (P≤0.001). The mean QuickDASH score was 41.83 ± 6.33 in the PRP group and 48.76 ± 5.08 in the methylprednisolone acetate group (P≤0.001). The mean SPADI score was 53.32 ± 7.49 in the PRP group and 59.24 ± 5.80 in the methylprednisolone acetate group (P≤0.001), indicating a significant improvement in the PRP group's pain and disability scores after 24 weeks. The rate of complications was similar between the two groups.ConclusionsOur findings suggest that IA PRP injections provide better long-term results than IA CS injections for managing FS. Platelet-rich plasma can be used as a treatment modality for better outcomes, particularly when the patient is contraindicated or refuses CS treatment. Further research is needed to evaluate the efficacy of these treatment modalities at different stages of FS and explore the potential benefits of ultrasound-guided injections.