Histologic sections of a normal ACL (A), sutured ACL (B) and sutured ACL with SIS (C). The sections are stained with Lendrum Masson’s trichrome; the collagen fibers are stained in yellow, the cytoplasm in red and the nuclei in blue. The ECM of both the Suture and Suture-SIS group have aligned collagen fibers, the collagen fibers in the Suture-SIS group stained denser, more compact arranged and contained less voids and less fat vacuoles. Neovasculature running parallel between the collagen fibers could be observed in both experimental groups. ×100.