MENLO PARK, Calif. -- The answer to intractable refractory tennis elbow may be a single injection of endogenous plasma, treated to increase the concentration of platelets, according to researchers here.
MENLO PARK, Calif., Oct. 23 -- The answer to intractable refractory tennis elbow may be a shot in the arm, according to researchers here.
In a small pilot study, 20 patients with long-term severe pain in elbow tendons were given either a single injection of endogenous plasma, treated to increase the concentration of platelets, or bupivacaine with epinephrine, said Allan Mishra, M.D., of the Stanford Medical Center.
The plasma patients had significant reductions in their pain scores, both compared with the patients who got bupivacaine (who served as a control group) and to baseline, Dr. Mishra and a colleagues reported in the November issue of the American Journal of Sports Medicine.
Indeed, after two years of follow-up. Dr. Mishra reported, patients getting the plasma reported a 93% reduction in their pain scores. Meanwhile, three of the five bupivacaine patients had withdrawn from the study or sought other treatment by the end of the first eight weeks.
Dr. Mishra speculated that the platelet-rich plasma contains a range of growth factors that repair damage to the tendons if they are present in great enough quantity.
"The body has an extraordinary ability to heal itself," Dr. Mishra said. "All we did was speed the process by taking blood from a different area, concentrating it, and putting it back into an area where there was relatively poor blood supply to help repair the damage."
The researchers noted that the study was small and unblinded, so that the results need to be confirmed in a larger randomized controlled trial.
The researchers enrolled 20 patients whose elbow pain had been severe for at least three months, and whose score on the 100-point visual pain analog scale was at least 60. In fact, the mean score was 82 and the pain had persisted for a mean of 15 months. Dr. Mishra reported.
The 15 plasma patients had had tendinosis for a mean of 15 months and baseline score on the pain scale was 80.3. The five patients in the control group had a mean duration of symptoms of 12 months and a baseline pain score of 86.
Patients in the plasma arm had 55 mL of blood collected, which was then spun down in a centrifuge. Two milliliters of the platelet-rich concentrate was buffered to physiologic concentration and injected in the affected arm.
The injected solution contained about 3.31 million platelets, or about 539% of the concentration found in the patient's whole blood.
The study found that eight weeks after treatment, plasma patients had a 60% improvement in their visual analog pain scores, versus 16% for the control patients, a difference that was statistically significant at P<0.001.
At that point, Dr. Mishra reported, a majority of the control patients decided to withdraw or seek other treatment, so that subsequent comparisons were made to the plasma patients' baseline scores.
At six months, the plasma patients reported an 81% improvement in pain scores, compared to baseline, and at the final follow-up (a mean of 25.6 months) they reported a 93% improvement. Both improvements were statistically significant at P<0.0001.
While some early studies have shown the platelet therapy to be useful in maxillofacial surgery, wound healing, microfracture repair, and in the treatment of plantar faciitis, it's still considered investigational. The procedure is not yet commercially available.
This study received some funding from Cell Factor Technologies of Warsaw, Ind., which provided the kit and materials required to perform the procedure. Dr. Mishra is a consultant for the company.