There are a few different types of injections that have been used for the treatment of tennis elbow, but there is little to suggest that one type of injection is better than any other.
Tennis elbow is a condition that causes chronic tendon damage to the tendon on the outside of the elbow joint. The tendon is usually damaged as a result of an overuse condition, such as sports or work activities. The type of tendon damage is called tendinosis, which causes a chronic tendon irritation and microscopic tears. When the damaged tendon is inspected under a microscope, the tendon is seen to have scar tissue and blood vessel formation -- evidence of a chronic healing process. What is not seen under the microscope is evidence of inflammation, as is the case with tendonitis.
Autologous Blood InjectionsAutologous blood injections are simply injections of your own blood. Similar to PRP, the theory behind the use of autologous blood is that injections of your own blood will stimulate a healing response in the affected tendon. The only difference between autologous blood and PRP is that the autologous injections are not a concentrated component of the blood.
Which Injection?There has been no good evidence that any one of these injections is better than another. In fact, in a recent study in the Journal of Hand Surgery, different injections were compared to injections of saline (placebo injections). The different injections were wrapped so patients wouldn't know which solution they were receiving, and all patients had blood drawn so that they wouldn't know if they were getting a blood injection. In the end, all of the patient groups showed improvement (including the placebo group), and none did significantly better that any other group.
This study demonstrates that probably one of the most important needs for healing of tennis elbow is time. Allowing the body time to heal can be one of the most effective treatments of many medical conditions. If an injection can help control the symptoms of tennis elbow pain while your body is healing, I think that is reasonable. The only treatment I personally do not use is PRP. The reason is that these injections are very expensive and have yet to show any benefit over injections that cost a small fraction of the cost. That said, PRP, and all of these injections, are generally safe and reasonable to discuss with your doctor.
Wolf JM, et al. "Comparison of Autologous Blood, Corticosteroid, and Saline Injection in the Treatment of Lateral Epicondylitis: A Prospective, Randomized, Controlled Multicenter Study" J of Hand Surg: Vol 36, Iss 8, Pg 1269-72, August 2011