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

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.