Background: Little attention has been focused on the effect of fat graft structure on in vivo performance. We hypothesized that a stable initial graft structure was important to fat graft take - similar to the importance of shear minimization in the take of skin grafts. The performance of fat grafts was assessed when suspended in two matrices that provided different durations of graft structural support: Matrigel, which resorbs over two months; and Puramatrix, which resorbs in one week.

Methods: Age and sex matched genetically identical mice were implanted with fat grafts consisting of the same number of purified adult adipocytes mixed with either Puramatrix or Matrigel. Control grafts composed of Matrigel alone, Puramatrix alone, or lipoharvested (unpurified) fat alone were also injected. Volume measurements and histological sections were taken at 1 week, 1 month and 3 months.

Results: Purified adipocytes/Matrigel grafts showed statistically greater longevity and volume maintenance versus all other groups.

Conclusions: Gradual resorption of scaffolding in this study was associated with improved graft longevity and volume maintenance, while immediate matrix resorption led to poor graft performance. These results suggest a potentially important role for a mechanically stable initial graft structure in the ultimate efficacy of fat graft take.