A new systematic review published in the Journal of Orthopaedic Surgery and Research suggests that combining micro-fragmented adipose tissue (MFAT) injections with knee arthroscopy may provide meaningful pain relief and functional improvement in knee osteoarthritis (KOA) patients, a population without many options.
Background: Regenerative Approaches Emerge for KOA
Knee osteoarthritis is a prevalent degenerative joint disorder, now increasingly seen not only among older adults but also in younger populations due to obesity and joint trauma. Current standard treatments, ranging from physical therapy to pharmaceuticals, often fall short, particularly in delaying or avoiding joint replacement.
Enter regenerative medicine: MFAT has potential due to its high concentration of mesenchymal stem cells (MSCs) and other growth factors known to support cartilage repair and reduce inflammation.
MFAT is often prepared via simple abdominal or thigh liposuction, then processed to retain cellular and bioactive elements for regeneration. When combined with arthroscopy, MFAT can be precisely delivered to affected areas. This review systematically assesses the efficacy and safety of such a combination for KOA.
In total, two randomized controlled trials and four retrospective studies, published between 2022 and 2025, were included.
Findings: Pain Relief and Functional Gains, with Limited Complications
Across all studies, patients who underwent MFAT injections during knee arthroscopy reported significant pain improvements, anywhere from a 44.4% to 62.2% reduction (via Visual Analog Scale). Improvements in joint function were also reported using WOMAC, KOOS, and Lysholm scores, though the magnitude varied from study to study.
Adverse effects were minimal overall. Most complications were mild, such as brief pain or swelling at the liposuction or injection site. A small number of cases involved lipoatrophy, joint effusion, or painful adipose nodules, but these were uncommon. No study reported severe or lasting adverse events related to the therapy.
Cartilage Health and Biomarker Outcomes
Some studies assessed the structural effects of the treatment. One research group utilized the Whole Organ Magnetic Resonance Imaging Score (WORMS) and found significant improvements in cartilage condition after the procedure. However, when bone metabolism markers (CTx-II, PIIINP) were measured, there were no marked changes following treatment. This suggests that while soft tissue repair was evident on imaging in some cohorts, the effects on underlying bone metabolism remain unclear from currently available data.
Limitations and Gaps in the Evidence
The authors of the review emphasize several major limitations, including a relatively few number of studies (six), follow-up durations generally short (12-48 months), and heterogeneity in methodologies, including rehab, outcome reporting, and lack of blinding in some studies, restrains the ‘generalizability’ of the findings.
Additionally, while nearly all outcomes favored the combined approach for pain and function, evidence regarding true cartilage regeneration, alterations in bone metabolism, and the durability of improvements is limited. The precise mechanisms by which MFAT, and particularly the MSC component, exerts its effects in the joint remain to be fully elucidated, with questions remaining about cell survival, engraftment, and long-term functional integration.
Future Directions: Toward Better Understanding and Implementation
The review’s authors highlight several directions for future investigation. For one, as with most regenerative medicine, we need more high-quality, large-scale RCTs with long-term follow-up. Additionally, we need more standardized MFAT processing methods and postoperative rehab protocols to clarify and optimize the therapy. Lastly, there are other combinations to consider, including platelet-rich plasma + MFAT, or other biologics.
References
Hu, X., Zhang, Z., Zhang, W. et al. Efficacy and safety of micro-fragmented adipose tissue combined with knee arthroscopy in the treatment of knee osteoarthritis: a systematic review. J Orthop Surg Res 20, 646 (2025). https://doi.org/10.1186/s13018-025-06006-5
