Intra-articular ACP Safe and Effective for Knee OA in Double-Blind Trial

Patients with knee OA receiving 3 weekly ACP intra-articular injections had statistically significant improvement in their overall WOMAC scores

Treatment of osteoarthritis (OA) consists of both non-pharmacologic and pharmacologic modalities. Platelet-rich plasma (PRP) or autologous conditioned plasma (ACP) is derived from autologous blood with a high platelet concentration in a small volume of plasma. Its use in OA patients has been associated with pain relief, improved function, and possible cartilage regeneration.1

ACP is thought to be beneficial by delivering growth factors in high concentration to focal areas of injury. Prior studies have shown that ACP induces proliferation of autologous chondrocytes and mesenchymal stem in an ovine model.2

To determine the safety and efficacy of ACP in the treatment of knee OA, researchers at the University of Missouri randomly assigned 30 patients to receive either ACP or saline placebo in a series of weekly injections for 3 weeks.3 Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores served as the primary efficacy outcome measure. Patients were followed for 1 year.

In the study, published in the American Journal of Sports Medicine,  the researchers found that WOMAC scores 1 week post-infusion were decreased when compared to baseline, a statistically significant decrease that persisted until the end of the study. One year after ACP administration, subjects had improved their overall WOMAC scores by 78% from their baseline score, compared with 7% for the placebo group.

Additionally, no adverse events were found to be associated with ACP administration.

Summary and Clinical Applicability

In this study, patients receiving 3 weekly ACP had statistically significant improvement in their overall WOMAC scores This study was limited by its size.

Further research should be conducted to determine which particular formulation of ACP is most effective for knee OA, because ACP is not currently standardized, and has varying contents of plasma, platelets, and white blood cells. Additionally, future studies should determine the optimal amount of ACP and address the frequency of injections.


1.     Halpern B, Chaudhury S, Rodeo SA, et al. Clinical and MRI outcomes after platelet-rich plasma treatment for knee osteoarthritis. Clin J Sport Med. 2013; 23:238.

2.     Drengk A, Zapf A, Stürmer EK, et al. Influence of platelet-rich plasma on chondrogenic differentiation and proliferation of chondrocytes and mesenchymal stem cells. Cells Tissues Organs. 2009; 189:317.

3.     Smith, PA. Intra-articular Autologous Conditioned Plasma Injections Provide Safe and Efficacious Treatment for Knee Osteoarthritis: An FDA-Sanctioned, Randomized, Double-blind, Placebo-controlled Clinical Trial. Am J Sports Med. 2016;  doi: 0363546515624678.