Over a few months, neither steroids nor platelet injections are any better than injections of inactive salt water when it comes to treating tennis elbow, according to new research.
Despite its name, tennis elbow - which is caused by overuse of tendons in the elbow - often affects people with strenuous jobs, not just athletes.
Common treatments include non-steroidal anti-inflammatory drugs, physical therapy and steroid injections. Recent research has also shown platelet injections to be a "promising" alternative, according to the study's authors.
In the new trial, those experimental injections were the most painful and after three months hadn't lessened patients' elbow pain or improved their function any more than steroids or a saline solution. But a Dutch orthopedic surgeon not involved in the study said it may not have lasted long enough to see an effect of so-called platelet-rich plasma, or PRP.
"Most of these studies… they look at the results after three or six months. And if you want to have a good sight of what PRP does, I think you should have a longer follow-up," said Dr. Taco Gosens, from St Elisabeth Hospital in Tilburg.
In his own research, about twice as many people with tennis elbow were better two years after a platelet injection than after standard steroid treatment - despite there being no difference between the groups at three months.
The current study, from Dr. Torkell Ellingsen and colleagues from Region Hospital Silkeborg in Denmark, included 60 people who'd had elbow tendon problems for at least three months.
The researchers randomly assigned each participant to an injection of platelets, steroids, or saline. Although Ellingsen's team originally intended to track pain and function in study volunteers for a year, most had dropped out of the trial or underwent other treatment by then.
After one month, pain had dropped by almost 10 points on a 50-point scale among people who'd had steroid injections, compared to less than two points for the platelet and saline groups. Elbow function had also improved significantly more for people injected with steroids.
However, at three months, any extra benefit due to steroids had disappeared and pain and functioning were similar across all three groups. Pain scores improved by between three and seven points from the start of the study, the researchers reported in The American Journal of Sports Medicine.
There were no serious side effects linked to any of the treatments.
Stanford University orthopedic surgeon Dr. Allan Mishra agreed with Gosens that the new study didn't follow patients for enough time to see the long-term effects of platelets, a treatment he uses often.
The findings are "interesting but inconclusive, or incomplete," he told Reuters Health. "I don't think 12 weeks is particularly helpful for patients or providers."
In his experience, Mishra said, "The PRP patients continue to improve, and the glucocorticoid patients revert back to normal."
Mishra and Gosens both said steroids only provide short-term relief - and may actually damage the tendon further with repeat injections.
For people who have had tendon problems for weeks rather than months or years, "watchful waiting" might be the most appropriate treatment, according to Gosens. After a year, he said, 80 percent of people with tennis elbow will be cured with that strategy.
For the rest, he recommends PRP or surgery. The platelet treatment does not require FDA approval - although the devices to purify the platelets do. PRP isn't covered by insurance, Gosens said, and should only be done as part of a clinical trial for now. The treatment runs for about $1,000.
"Patients should be aware that it's experimental still," Gosens said.