In addition, the parameters to evaluate new bone formation were variable. New bone formation and percentage of vital bone are different methods to measure bone formation, and the data from different methods could not be combined or analyzed together. Furthermore, the BMAC evaluated in test groups were prepared differently and were harvested from different sources (tibia or iliac). The control groups with no BMAC were also slightly different and included different graft materials. Thus, the heterogeneity of the data prevents any meaningful data analysis.