ObjectiveTo investigate the effect of ultrasound-guided anterior injection of platelet-rich plasma (PRP) combined with routine physiotherapy on pain and functional improvement in patients with rotator cuff injury.MethodsThe patients with rotator cuff injury treated in the Department of Rehabilitation Medicine, the Affiliated Hospital of Southwest Medical University from August 2017 to June 2018 were randomly divided into control group and PRP group. The control group was treated with routine physiotherapy for 4 weeks, and the PRP group was treated with PRP injection guided by musculoskeletal ultrasound (once a week, two injections) combined with routine physiotherapy for 4 weeks. The Shoulder Pain and Disability Index (SPADI) and the European Shoulder Association Constant-Murley Score (CMS) were used to evaluate the changes of pain and function before intervention, 12 weeks after intervention and 24 weeks after intervention.ResultsFinally, 65 patients were included, with 33 in the control group and 32 in the PRP group. Compared with the control group, there were significant differences in the CMS and SAPDI scores between the PRP group and the control group at 12 and 24 weeks after intervention (P<0.05), except before intervention (P>0.05). Twelve and 24 weeks after intervention, the CMS scores of the two groups were higher than those before intervention, while the SPADI scores were lower than those before intervention (P<0.05). The results of repeated measures analysis of variances showed that there was no statistical significance in group effect of CMS or SAPDI scores (F=2.753, P=0.102; F=2.724, P=0.104), but the time effects of CMS and SAPDI scores were statistically significant (F=251.002, P<0.001; F= 1 846.753, P<0.001), and there was interaction between group and time (F=4.931, P=0.020; F=36.405, P<0.001).ConclusionAnterior injection of PRP guided by musculoskeletal ultrasound combined with conventional physiotherapy is more effective than conventional physiotherapy in relieving shoulder pain and improving shoulder joint function.