Cost implications of treatment need discussionThis study provides a useful additional information with regard to the merits of injection therapy in the management of resistant elbow tendinopathy. It would have been helpful if the authors had commented on the relative costs (time/money) of the treatments given the current pressures on minimising health care costs. There are variety of systems available for producing platelet rich plasma injections which can result in a significant cost burden to the health care provider or patient. Studies such of this will be picked up by manufacturers of these systems and used in their marketing.However if there is no significant difference in clinical outcome by using simple autologous blood injections then the authors should conclude that there is no enhanced benefit from using PRP and its associated costs are not justified. The volume of blood injected was not described in the section on "technique" and this should be corrected to make the methodology clear and reproducible. It is assumed that the 1.5 mL 'siphoned from the buffy coat layer' was used for the PRP injectionbut this needs to be clarified. Finally,whether it is the injection procedure and physical disruption of the tissue or the contents of the syringe that are important in stimulating a response remains unclear.
Conflict of Interest: