'Personalized' use of platelet-rich plasma injections may be the future of OA treatment
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Understanding the complex associations between pain, function and structural factors in the joints may allow clinicians to use intraarticular injections more effectively in osteoarthritis, according to a speaker at the 2021 OARSI World Congress.
“Disease-modifying drugs for symptomatic, radiographic OA remain lacking,” Constance R. Chu, MD, FAAOS, FAOA, professor and vice chair of research in the department of orthopedic surgery at Stanford University, said in her presentation. “Current injection therapies are, at best, palliative.”
Chu suggested that interest in using intraarticular injections of platelet-rich plasma or cell therapies could yield improved outcomes over traditional modalities.
In the past decade, a small number of clinical trials have shown that platelet-rich plasma injections can be highly effective in OA, particularly with regard to pain relief, according to Chu. However, the effects can be variable between men and women, people in different age groups and those with comorbid health conditions, including obesity.
One such study was published by Chu’s group in the Journal of Orthopedic Research. While the findings showed that platelet-rich plasma injections yielded improvements in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness and function that met primary endpoints, the effect was “variable” from patient to patient. Some patients showed as much as a 20-point improvement in WOMAC pain, while others worsened by the same amount. “Over half did not show any clinical improvement,” Chu said.
In addition, scores at 1 month correlated with those at 6 months. “Further study is merited to determine who will respond and who will not,” Chu said.
The good news is that patients who did show improvement in WOMAC parameters demonstrated improved gait and were able to load their joints after platelet-rich plasma injections. “It rebuts the idea that it is just a placebo effect,” Chu said. “These data highlight that treating pain and function is not enough.”
If there is another point that these data highlight, it is that certain patients may be predisposed to respond to plasma joint injections, while others may not.
This, in turn, raises the issue of whether it may be beneficial to have predictive biomarkers or other predictive factors for individuals who do not yet have osteoarthritis, but who have “pre-OA,” according to Chu.
Some of those predictors may include structural factors such as T2 or UTE-T2; biological markers including a proteomic profile, an inflammation panel and a molecular signature; and mechanical factors such as elevated KAM or KFAHS. “These markers of OA risk are measurable, meaningful and potentially reversible,” Chu said.
Perhaps the most important group to target includes individuals who have sustained a joint injury but who do not yet have OA. For example, platelet-rich plasma IA injections may be beneficial in those who have torn an anterior cruciate ligament and, therefore, have a strong likelihood of developing OA.
A sustained release formulation would be ideal, allowing the positive impacts of plasma to be distributed into the joint over time.
“This is the future of injections,” Chu said, describing formulations that are “personalized and adaptable” to individual patients and their joints. “This is not as foreign or radical as it may seem. There is definitely a future for intraarticular injections in knee OA prevention. Treating pain and symptoms alone is not enough.”
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Chu CR. Is There a Future for Intra-Articular Injections in Joint Preservation? Presented at: OARSI 2021 World Congress on Osteoarthritis; April 29-May 1 (virtual meeting).
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