- Participants will acquire the most novel information on the benefits of using blood-derived products, from bench to bedside.
15.1.2 - How Does PRP/BMAC Work?
Conservative strategies to treat osteoarthritis (OA) have modest efficacy, with short-lasting clinical results, and are not able to arrest the disease process. Research efforts have been made to develop new minimally invasive disease-modifying procedures. Among these, orthobiologics are gaining increasing interest due to the availability of several new products with promising biologic potential. These approaches exploit the high concentrations of growth factors, cytokines, and bioactive molecules of blood derivatives, as well as the presence of mesenchymal stromal cells (MSCs) in tissue derived concentrates like bone marrow aspirate concentrates (BMAC), aiming at improving symptoms, a satisfactory joint function, and possibly slowing down OA progression [1,2].
Platelet Rich Plasma (PRP) is increasingly applied due to its safety, low costs, and simple preparation technique to obtain its biologically active content. PRP seems to promote a positive joint environment, favoring the restoration of a homeostatic balance in OA joints. A recent systematic review on animal studies evaluated intra-articular PRP injections as treatment for OA joints . Forty-four articles were included, for a total of 1251 animals. PRP injections showed clinical effects in 80% and disease-modifying effects in 68% of the studies, attenuating cartilage damage progression and reducing synovial inflammation, coupled with changes in biomarker levels. Intra-articular PRP injections showed disease-modifying effects in most preclinical studies, both at the cartilage and synovial level. These findings in animal OA models can play a crucial role in understanding mechanism of action and structural effects of this biological approach. Nevertheless, the overall low quality of the published studies warrants further preclinical studies to confirm the positive findings, as well as high-level human trials to demonstrate if these results translate into disease-modifying effects when PRP is used in the clinical practice to treat OA. Disease-modifying effects are still controversial in humans, while several data are available on the clinical effects of PRP.
Despite the presence of different platelet concentrates, clinical evidence supported the safety and effectiveness of intra-articular PRP injections for the treatment of knee OA, with better clinical results compared to saline, corticosteroids, and hyaluronic acid injections at 6 and 12 months of follow-up. Some studies also suggest that PRP benefits can be perceived by patients beyond 24 months and can delay the need for total knee arthroplasty [4,5]. Recently, some researchers also supported the effectiveness of subchondral PRP injections, reporting positive results in reducing pain and improving functional status, although more studies are needed in this direction.
BMAC is a combination of biologically active proteins and cells obtained through a mini-invasive and technically easy procedure. Clinical studies investigating the use of BMAC to address OA evaluated mainly the knee injective treatment, reporting promising results in terms of safety and effectiveness for symptom management. Nevertheless, evidence is much lower for BMAC than for PRP. The few available comparative studies do not show BMAC superiority over the other intra-articular options like PRP and the Stromal Vascular Fraction (SVF), and the benefits versus the placebo saline injections remain to be proven as well . A new application of BMAC has been recently suggested to further exploit its potential by targeting the subchondral bone. This strategy demonstrated promising clinical results, especially in patients with knee OA and subchondral bone alterations .
Due to the higher costs and invasive nature, more data are needed to justify BMAC treatment and subchondral bone injections, while PRP appears to be a suitable option to provide short-term benefit in patients affected by knee OA. Further high-level studies are needed to better clarify potential and limitations of these biological approaches, identifying the most suitable products and formulations, as well ideal patient candidate, for the management of joints affected by OA.
1) Filardo G, Kon E, Longo UG, Madry H, Marchettini P, Marmotti A, Van Assche D, Zanon G, Peretti GM. Non-surgical treatments for the management of early osteoarthritis. Knee Surg Sports Traumatol Arthrosc. 2016 Jun;24(6):1775-85. doi: 10.1007/s00167-016-4089-y.
2) Mariani E, Roffi A, Cattini L, Pulsatelli L, Assirelli E, Krishnakumar GS, Cenacchi A, Kon E, Filardo G. Release kinetic of pro- and anti-inflammatory biomolecules from platelet-rich plasma and functional study on osteoarthritis synovial fibroblasts. Cytotherapy. 2020 Jul;22(7):344-353. doi: 10.1016/j.jcyt.2020.02.006.
3) Boffa A, Salerno M, Merli G, De Girolamo L, Laver L, Magalon J, Sánchez M, Tischer T, Filardo G. Platelet-rich plasma injections induce disease-modifying effects in the treatment of osteoarthritis in animal models. Knee Surg Sports Traumatol Arthrosc. 2021 Aug 2. doi: 10.1007/s00167-021-06659-9
4) Filardo G, Previtali D, Napoli F, Candrian C, Zaffagnini S, Grassi A. PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials. Cartilage. 2020 Jun 19:1947603520931170
5) Di Martino A, Di Matteo B, Papio T, Tentoni F, Selleri F, Cenacchi A, Kon E, Filardo G. Platelet-Rich Plasma Versus Hyaluronic Acid Injections for the Treatment of Knee Osteoarthritis: Results at 5 Years of a Double-Blind, Randomized Controlled Trial. Am J Sports Med. 2019 Feb;47(2):347-354. doi: 10.1177/0363546518814532.
6) Kon E, Boffa A, Andriolo L, Di Martino A, Di Matteo B, Magarelli N, Marcacci M, Onorato F, Trenti N, Zaffagnini S, Filardo G. Subchondral and intra-articular injections of bone marrow concentrate are a safe and effective treatment for knee osteoarthritis: a prospective, multi-center pilot study. Knee Surg Sports Traumatol Arthrosc. 2021 Mar 27. doi: 10.1007/s00167-021-06530-x.
7) Cavallo C, Boffa A, Andriolo L, Silva S, Grigolo B, Zaffagnini S, Filardo G. Bone marrow concentrate injections for the treatment of osteoarthritis: evidence from preclinical findings to the clinical application. Int Orthop. 2021 Feb;45(2):525-538. doi: 10.1007/s00264-020-04703-w.