Effectiveness of platelet rich plasma on hemiplegic shoulder pain

Objective: In this study, our aim was to examine the effects of platelet rich plasma (PRP) on pain and functional outcomes in patients with hemiplegic shoulder pain. We compared the effects of PRP against saline solution by designing a double blind, randomized, prospective study. Materials and Methods: 55 patients with hempilegia of more than 3 months duration, who complained of shoulder pain for more than 2 weeks, and who were between 18-80 years of age were evaluated for inclusion. 6 of these patients did not meet the inclusion criteria and 6 more patients rejected enrollment. A total of 43 patients were included and randomized. All patients received a total of 3 injections, one week apart. First group received PRP injections while the second group received placebo injections. Patients in the treatment group received intraarticular injections to their affected shoulders consisting of PRP that was obtained from the centrifugation of the subjects' venous blood, while the patients in the control group received intraarticular saline injections of the same volume. All patients continued receiving neurologic rehabilitation in addition to the injections. Subjects and researchers were blind to treatment allocations. After 3 months of follow up, 40 patients completed the trial. Primary outocome measure was movement-induced pain score (VAS) and secondary outcome measures were spotaneous pain score, shoulder passive range of motion (ROM), functional independence measure score and the amount of paracetamol used. All subjects were evaluated at baseline, 1 week, 1 month and 3months after the completion of the last injection. Results: Both groups showed an improvement in spontaneous and movement-related pain scores and shoulder passive ROM values on 1st and 3rd month visits (p<0,05). No significance difference was detected between groups. Similarly, FIM scores improved significantly in both groups (p<0,05) but no difference was found between groups. Paracetamol use did not differ significantly between groups. Discussion: Platelet rich plasma is the cellular plasma component of blood that is obtained by centifugation of whole blood and that contains higher platelet concentrations. Introduction into the tissues of this platelet suspension that is rich v in proteins and growth factors aims to facilitate healing by increasing angiogenesis, epithelisation, cell differentiation and stimulation of extracellular matrix formation in tissues that are old and with poor regeneration capabilities. Based on these beneficial effects, we hypothesized that PRP may alleviate hemiplegic shoulder pain, however no difference was detected between groups. The non-superiority of PRP over placebo may be due to the needle stimulus effect in placebo group, preparation of PRP suspension, lack of activator use in PRP preparation, aspirin use, the etiologic heterogenicity of hemiplegic shoulder pain and chronicity of pain in our patient population. Concurrent patient education and a formal rehabilitation and exercise program may also have contributed to the positive outcomes. There is still need for further research that incorporates subgroup analyses of subjects with acute and chronic stroke, presence or absence of subluxation that includes larger numbers of patients and also examines the effects of activator use during PRP preparation. Keywords: Hemiplegia, pain, platelet-rich plasma, shoulder, stroke