Joost Peerbooms

69 PRP in lateral epicondylitis Figure 1. Flow diagram of a trial of injection therapy for chronic lateral epicondylitis. The dia- gram includes the number of patients actively followed up at different times during the trial. PRP Preparation In the group randomized to receive PRP, the patient’s own platelets were collected with the Recover System (Biomet Biologics, Warsaw, Indiana). This device uses a desktop-size centrifuge with disposable cylinders to isolate the platelet-rich fraction from a small volume of the patient’s anticoagulated blood, drawn at the time of the procedure. As part of the double-blind procedure, blood was also collected from the patients in the control group. In sum, 27 mL of whole blood was collected from the uninvolved arm into a 30-mL syringe that contained 3 mL sodium citrate. The platelet-rich fraction was prepared according to the instructions of the Recover System. Approximately 3 mL PRP was obtained for each patient. The PRP was then buffered to physiologic pH using 8.4% sodium bicarbonate, and bupivacaine hydrochloride 0.5% with epinephrine (1:200000) was added. No activating agent was used. After masking the tubes with opaque tape, the investigator returned and injected 3 mL of this PRP into the patient. The total time from blood draw to injection in the patients was about 30 minutes. No specialized equipment was required, other than the centrifuge to process the Recover disposable cylinders. All the procedures were performed in the same office setting by 5