Are there biologic factors of good prognosis after a platelet rich plasma (PRP) injection for tendinopathies ?

Background : The aims of this study were to evaluate the effect of a single PRP injection followed by a standardized reeducation protocol among patients suffering from different tendinopathies, but otherwise healthy, and to determine the biomarkers that constitute good prognosis factors, if any.
Methods : 48 patients suffering from different tendinopathies and refractory to conventional physiotherapy were treated with a single PRP injection. Prior to the injection, a blood sample was drawn and some biological parameters (glycemia, cholesterolemia,...) were measured. A pain assessment was then made using a Visual Analog Scale of pain (VAS) and a pressure algometer. The same assessment was carried out after 6 weeks and 12 weeks when possible.
Results : There is an overall significant improvement in VAS score at the end of the 12 weeks follow- up. However, no correlation was found between the evolution of the clinical scores and the biological parameters measured.
Conclusion: A PRP injection followed by a program of eccentric rehabilitation positively affects the algo-functional scores of patients with tendinopathies who were refractory to conventional physio- therapy, whatever the initial values of the measuured biological parameters.