2015 ISAKOS Biennial Congress ePoster #210

Comparison Between Platelet-Rich Plasma Therapy vs Acetaminophen in the Treatment of Primary Knee Osteoarthritis

Felix Vilchez-Cavazos, MD, PhD, Monterrey, NL MEXICO
Mario Simental-Mendía, PhD, Monterrey, NL MEXICO
Carlos Acosta, MD, PhD, Monterrey MEXICO
Oscar Mendoza, MD, Zapopan, Jalisco MEXICO
Salvador Said, PhD, Monterrey MEXICO
Herminia Martinez, PhD, Monterrey MEXICO

Hospital Universitario, UANL, Monterrey, Nuevo Leon, MEXICO

FDA Status Not Applicable

Summary: To compare clinical response of acetaminophen vs intra-articular platelet-rich plasma injections in patients with primary knee osteoarthritis




Osteoarthritis is a progressive and degenerative articular cartilage disease. Acetaminophen is the first-line treatment for primary knee osteoarthritis and is focused only in pain control rather than modifying biochemical environment of the joint. Injections of autologous platelet-rich plasma have been proposed as a therapeutic alternative. Platelet-rich plasma contains a variety of cytokines including IL-1ra, which is capable to counteract IL-1ß inflammatory effects.


To compare clinical response of acetaminophen vs intra-articular platelet-rich plasma injections in patients with primary knee osteoarthritis and evaluate the concentration of IL-1ra in platelet-rich plasma preparations.
Study Design: Randomized, prospective controlled trial.


A total of 49 patients with clinically and radiographically documented osteoarthritis were included. Osteoarthritis was graded using the Kellgren-Lawrence radiographic classification scale. Patients were randomized into two groups: 23 patients were treated with acetaminophen in doses of 500 mg every 8 hr during 6 weeks, and 26 patients received three intra-articular injections of platelet-rich plasma (specifically, autologous pure platelet-rich plasma). An orthopedist performed infiltration once every two weeks into affected knee. All patients were evaluated with the Visual Analogue Scale (VAS) and Western Ontario and McMaster Universities (WOMAC) score before treatment and at 6 and 12 weeks after beginning treatment. Platelet, leukocyte and IL-1ra concentrations were analyzed on each platelet-rich plasma preparations.


Both treatments showed a significant decrease in pain level of VAS score at 6 and 12 weeks (p<0.01). However, decrease in platelet-rich plasma group was greater than acetaminophen group (p<0.01). Patients treated with platelet-rich plasma had a significant improvement in knee function, stiffness and pain parameter by week 6 and was sustained at week 12 (p<0.01). No significant improvement was observed in patients treated with acetaminophen (p>0.05). Comparison between the two total WOMAC scores at 12 weeks follow up notes a clear amelioration in favor of platelet-rich plasma injections (26.3 against 11.9; p<0.01). The average numbers of platelets in platelet-rich plasma preparations increased 2.1 times over total blood, whereas leukocytes were only 0.52 k/mL, 13.3 times lower than total blood. Therapeutic concentrations of IL-1ra were detected in platelet-rich plasma samples (358.9 ± 206.3 pg/mL).


Treatment with platelet-rich plasma injections showed a significant better clinical outcome than the treatment with acetaminophen, with sustained lower EVA and WOMAC scores. Pure platelet-rich plasma therapy could modify positively inflammatory joint environment by counteract IL-1ß action.