Centrifuging the adipose graft through a screen gently re-sizes the graft so that it better adheres to the shape of the defect.  Excess pressure that adipose cells are subjected to using other emulsification steps leads to damaged or dead cells.  Processed adipose grafts are made of a collagen extra cellular matrix embedded with various cells to include adipocytes, mesenchymal stem cells and endothelial progenitor cells.  This cellular enriched matrix can serve as a scaffold for cells migrating from marrow and therefore have been shown to enhance healing, especially inside of a joint.  Inside the joint, bleeding occurs after injury, but no fibrin-platelet plug is observed to form. Circulating intra-articular plasmin breaks down the fibrin plug as fast as it can form.  While human Platelets release a fast-acting plasmin inhibitor, the high levels of plasminogen in the synovium overwhelms the natural process of the platelet fibrin clot.  Thus, healing of tissue inside a joint has proved difficult. Tissue outside the joint such as the medial collateral ligament is typically not exposed to synovial fluid after injury and is not as challenging of a tissue to heal. While the cellular composition of the two ligaments are similar, their microenvironments are different. Scaffolds that are not made out of fibrin, such as collagen, the primary structure of fat, does not degrade in the presence of plasminogen. The ideal biologic tissue inside the joint should contain platelets to prevent premature degradation, collagen from fat or other sources, growth factors, and stem cells to begin the tissue regeneration process.