Early healing processes of free tendon grafts within bone tunnels is bone-specific: a morphological study in a rabbit...

In order to function as effective ligament replacements, free tendon grafts must become firmly healed into bone tunnels as soon as possible. We hypothesized that graft incorporation would be bone-specific. Free semitendinosus tendon grafts were inserted into drill holes in a lapine medial collateral ligament reconstruction model; thus, creating tibial and femoral bone-specific incorporation sites. Femur-semitendinosus tendon-tibia complexes were harvested from 26 rabbits for histological analysis at various healing times: 0, 6, 12, or 24 weeks post-surgery. Incorporation and remodeling of the graft in the chondral callus was much more extensive at the cancellous-filled femoral insertion than within the marrow-dominated tibial insertion, suggesting that tendon graft healing may depend on the cancellous bone architecture at the graft site.