Microfragmented Adipose Tissue versus Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis: Letter to the Editor

Dear Editor: Biologic therapies have a huge potential in orthopaedic conditions such as knee osteoarthritis (KOA). Recently, numerous reviews and meta-analyses have been published in the field of regenerative medicine. Unfortunately, the lack of biologic product standardization and the concomitant use of different therapies do not allow consistent conclusions on their efficacy. Among others, platelet-rich plasma (PRP), stromal vascular fraction (SVF), cultured bone marrow, and adipose tissue–derived mesenchymal stem cells are the ones extensively tested. Microfragmented adipose tissue (MF-AT) has risen as an alternative therapy that needs a minimal manipulation approach. The article by Zaffagnini and coworkers has provided an interesting insight into the role of autologous MF-AT on KOA treatment. However, we would like to raise some concerns on the methods and conclusions of the study. MF-AT efficacy in KOA is not evidence based yet. MFAT has not been found superior in terms of efficacy compared with similar treatments that need less manipulation. Randomized placebo-controlled trials are missing. To the best of our knowledge, Zaffagnini et al have published 1 of the 3 existing randomized clinical trials that use MF-AT to treat KOA. Dallo et al found an improvement on functional scales in both groups (the one treated with MF-AT and the one treated with PRP and hyaluronic acid), without clear benefits in the experimental group. In their study, Peretti et al did not find significant differences in their preliminary results comparing arthroscopy versus arthroscopy and MF-AT injection. Concerning objective outcomes, magnetic resonance imaging (MRI) performed by Zaffagnini et al to evaluate KOA improvement or progression showed no differences after MFAT injection. In contrast, as already stated in a recent systematic review, SVF has proven significant improvement not only in subjective outcomes but also in radiological findings in MRI between baseline and a 12or 24-month control. Thus, MF-AT should not be considered the first-line biologic treatment for KOA. Among adipose-derived biological products, SVF should be considered first. A great cell population with a great amount of adipose stem cells that can rapidly differentiate into all mesodermal lines is only acquired through enzymatic digestion. The end product acquired via nonenzymatic digestion is not strictly cellular stromal vascular material but a combination of cellular debris, blood cells, and components of extracellular matrix. The role of these molecules in tissue regeneration is still unclear, and superiority versus SVF is unproven. Contrary to MF-AT treatment, and as already stated in a recent systematic review, SVF is a safe and clinically and radiologically effective treatment for KOA. For all the reasons mentioned above, we firmly believe that the statement ‘‘compared with an enzymatically processed lipoaspirate, MF-AT secreted a higher amount of growth factors and cytokines involved in tissue repair’’ can be confusing, so KOA tissue regeneration cannot be guaranteed.