In recent years, fat treatments administered for structural reconstruction, repair, or replacement are being increasingly offered at clinics across the country. These treatments contain both autologous cells that are often referred to as "stem cells" or "MSCs" and extra-cellular matrix (ECM). Cell therapies containing ECM are thought to have the following advantages over treatments prepared using enzymatic digestion: (1) preservation of the stromal vascular niche, which allows time-release of the regenerative factors; (2) release of bioactive molecules by exosomes, which have been demonstrated to be significantly greater in mechanically processed fat than enzymatically processed fat; and (3) maintenance of the structural and morphologic unit, which is thought to increase cell efficacy by making the cells more resilient to the harsh conditions in the recipient environment. Case reports investigating the use of autologous fat treatments show promise, but a number of questions remain unanswered. Agents injected into the joint tend to be quickly cleared from the body and ECM itself has the potential to produce inflammatory signals and induce osteoarthritis.