Bone-demineralized bone-bone graft for ligament reconstruction in rats

Bone-tendon-bone (B-T-B) type grafts were prepared for ligament reconstruction by harvesting the radius from rats, wrapping both ends of each bone with a laboratory film leaving only the central 10 mm exposed, and demineralizing the central part by immersing the bone in 1.75% HCl solution. In the grafts prepared, the central part of the bone became semi-translucent and flexible while the ends remained as hard bone tissue, thus forming a B-T-B type graft. The tensile strength of the grafts was greater than that of the medial collateral ligaments of the rats and about the same as of their anterior cruciate ligaments. No inflammation or other adverse reaction was noticed in experimental subcutaneous transplantation and the grafts showed excellent biocompatibility. In experimental ligament reconstruction, the test animals did not show any impairment on gait. There was invasion of fibroblasts into the graft at 4 weeks, and the fibroblasts were found through the whole graft and what looked like ligament tissue could be seen macroscopically at 8 weeks. Besides, bone tissue had infiltrated into the inside cavity of the non-demineralized part of the graft and proliferation, resulting in good bone union. The results obtained suggest that the grafts prepared in this study have a sufficient potential as B-T-B type grafts for ligament reconstruction.