Objective:To compare the clinical effects of platelet-rich plasma (PRP) and sodium hyaluronate on rotator cuff injury.Methods:From February 2022 to December 2022, 226 patients with rotator cuff injury caused by military training were treated at Department of Orthopaedics, Jinling Hospital, School of Medicine, Nanjing University. They were all male, aged (24.5±3.7) years, and their time from injury to treatment was (4.6±2.2) months. They were divided into 2 even groups according to different treatments: an observation group of 113 cases into whose subacromial space PRP was injected, and a control group of 113 cases into whose subacromial space sodium hyaluronate was injected. In both groups, the injection was performed once a week for consecutive 3 weeks. The 2 groups were compared in terms of visual analogue scale (VAS) and Constant-Murley shoulder function scale (CMS) before treatment and 4 and 8 weeks after treatment, and the levels of TNF- α and IL-6 in the shoulder synovial fluid before treatment and 8 weeks after treatment. Results:There was no statistical difference between the 2 groups in general clinical data before treatment, indicating comparability ( P>0.05). At 4 and 8 weeks after treatment, compared with the pre-treatment values, the VAS scores were significantly decreased and the Constant-Murley scores significantly increased in both groups ( P<0.001). At 4 and 8 weeks after treatment, the VAS scores in the observation group (3.1±0.9 and 1.5±0.5) were significantly lower than those in the control group (3.7±0.8 and 2.3±0.6) while the Constant-Murley scores in the observation group (58.6±4.5 and 72.2±4.1) significantly higher than those in the control group (55.2±5.3 and 67.8±5.0) ( P<0.001). At 8 weeks after treatment, the levels of TNF- α and IL-6 in the 2 groups were significantly lower than the levels before treatment ( P<0.001). At 8 weeks after treatment, the levels of TNF- α and IL-6 in the observation group [(2.9±0.9) μg/L and (0.8±0.2) μg/L] were significantly lower than those in the control group [(4.0±0.4) μg/L and (1.1±0.4) μg/L] ( P<0.001). Conclusion:Injection of PRP or sodium hyaluronate can relieve pain and improve shoulder function obviously in patients with rotator cuff injury, but PRP is superior to sodium hyaluronate in the treatment of rotator cuff injury.