Efficacy of Platelet-Rich Plasma Injections
PRP has been used in surgeries to promote cell regeneration since 1987,and a growing body of evidence shows it is a viable treatment for tendinosis. Not until recently, though, have experts researched and debated whether or not platelet-rich plasma (PRP) injections are an effective treatment for osteoarthritis.
Nearly all of the research investigating the use of PRP to treat osteoarthritis and other cartilage defects has been done since 2000, and the vast majority of research articles on the topic have been published since 2010.
Knee Osteoarthritis Treated with PRP
Researchers studying PRP and osteoarthritis often work with patients who have knee osteoarthritis, a condition that experts estimate will affect nearly half of all Americans at some point during their lives. Two clinical studies that examine PRP to treat knee arthritis are described below.
One study, published in 2013, involved 78 patients with osteoarthritis in both knees (156 knees). Each knee received one of three treatments: 1 PRP injection, 2 PRP injections, or 1 placebo saline injection. Researchers evaluated the subjects’ knees 6 weeks, 3 months, and 6 months after injection. Researchers found:
Knees treated with 1 or 2 PRP injections saw a reduction in pain and stiffness as well as improvement in knee function at 6 weeks and 3 months.
At the 6-month mark positive results declined, though pain and function were still better than before PRP treatment.
The group that received placebo injections saw a small increase in pain and stiffness and a decrease in knee function.
The platelet-rich plasma used in this clinical study had 3 times the platelet concentration of normal blood and had been filtered to remove white blood cells.
A second, smaller study examined patients who had experienced mild knee pain for an average of 14 months. Each arthritic knee underwent an MRI to evaluate joint damage and then received a single PRP injection. Patients’ knees were assessed at the 1 week, 3 month, 6 month and 1 year marks. In addition, each knee underwent a second MRI after one year. Researchers found:
One year after receiving a PRP injection, most patients had less pain than they did the year before (though pain had not necessarily disappeared).
MRIs showed that that the degenerative process had not progressed in the majority of knees.
While knee cartilage did not seem to regenerate for patients, the fact that the arthritis did not worsen may be significant. Evidence suggests that an average of 4 to 6% of cartilage disappears each year in arthritic joints.