Introduction: The aim of this study was to analyse mechanically and histologically the osteointegration of porous-surfaced ceramic implants made of an alumina matrix composite (AMC) by assessing maximum shear strength and histomorphometric bone ongrowth.
Methods: The surfaces of the cylindrically shaped AMC test implants were characterised by a porosity of 40% and a pore size of 150 to 300 microm. A total of 24 test cylinders was implanted bilaterally into the femurs of 6 female adult Goettinger minipigs. 12 weeks after surgery the animals were sacrificed. 12 test implants were used for a push-out test and 12 test implants were evaluated histologically.
Results: The mean maximum shear strength of the bone-implant interface was 7.6 +/- 2.0 MPa. Direct bone attachment was found in 7.4 +/- 3.4% of the histologically analysed surfaces.
Conclusion: In summary, porous-surfaced AMC test implants demonstrated good mechanical stability in spite of a low percentage of bone ongrowth. This discrepancy could potentially be explained by bone ingrowth into the pores and subsequent interlocking mechanisms.