Osseointegration of hollow porous titanium prostheses loaded with cancellous bone matrix in rabbits

This study aimed to observe the osseointegration of hollow porous titanium prostheses (HPTP) loaded with cancellous bone matrix (CBM) in rabbits using histological and biomechanical perspectives. Experimental samples were implanted into the lateral femoral condyles of 66 New Zealand rabbits, allocated into the following groups: non-porous prosthesis group (Group A, n=22); HPTP group (Group B, n=22); HPTP+CBM group (Group C, n=22). The rabbits were sacrificed at 3, 8 and 12 weeks, postoperatively. X-ray analyses, microscopy techniques and morphological measurement software and mechanical tests were used for evaluation. At each time point, the tissues surrounding the implants were similar in all of the groups, with bony in-growth into the 2-mm round holes observed for the defects in Groups B and C. However, the internal bone formation was significantly better in Group C than in Group B at different time points (P<0.01). Biomechanically, the pull-out forces were significantly greater in Groups B and C than in Group A (P<0.01), with no difference between Groups B and C (P>0.05). These results suggest that bone can grow into the cavities of HPTP to achieve more stable locking fixation, and those osteogenic materials, such as CBM, can enhance osteogenesis to achieve better osseointegration between the implant and the host bone.