Comparative study in vivo of the osseointegration of 3D-printed and plasma-coated titanium implants

BACKGROUND Total hip arthroplasty is a common surgical treatment for elderly patients with osteoporosis,particularly in postmenopausal women.In such cases,highly porous acetabular components are a favorable option in achieving osseointegration.However,further discussion is needed if use of such acetabular components is justified under the condition of normal bone mass.AIM To determine the features of osseointegration of two different types of titanium implants[3-dimensional(3D)-printed and plasma-coated titanium implants]in bone tissue of a distal metaphysis in a rat femur model.METHODS This study was performed on 20 white male laboratory rats weighing 300-350 g aged 6 mo.Rats were divided into two groups of 10 animals,which had two different types of implants were inserted into a hole defect(2×3 mm)in the distal metaphysis of the femur:GroupⅠ:3D-printed titanium implant(highly porous);GroupⅡ:Plasma-coated titanium implant.After 45 and 90 d following surgery,the rats were sacrificed,and their implanted femurs were extracted for histological examination.The relative perimeter(%)of bone trabeculae[bone-implant contact(BIC%)]and bone marrow surrounding the titanium implants was measured.RESULTS Trabecular bone tissue was formed on the 45th day after implantation around the implants regardless of their type.45 d after surgery,group I(3D-printed titanium implant)and groupⅡ(plasma-coated titanium implant)did not differ in BIC%(83.51±8.5 vs 84.12±1.73;P=0.838).After 90 d,the BIC%was higher in group I(87.04±6.99 vs 81.24±7.62;P=0.049),compared to groupⅡ.The relative perimeter of the bone marrow after 45 d did not differ between groups and was 16.49%±8.58%for groupⅠ,and 15.88%±1.73%for groupⅡ.Futhermore,after 90 d,in groupⅠthe relative perimeter of bone marrow was 1.4 times smaller(12.96±6.99 vs 18.76±7.62;P=0.049)compared to the relative perimeter of bone marrow in groupⅡ.CONCLUSION The use of a highly porous titanium implant,manufactured with 3D printing,for acetabular components provides increased osseointegration compared to a plasma-coated titanium implant.

Osseointegration of porous titanium and tantalum implants in ovariectomized rabbits:A biomechanical study

BACKGROUND Today,biological fixation of uncemented press-fit acetabular components plays an important role in total hip arthroplasty.Long-term stable fixation of these implants depends on the osseointegration of the acetabular cup bone tissue into the acetabular cup implant,and their ability to withstand functional loads.AIM To compare the strength of bone-implant osseointegration of four types of porous metal implants in normal and osteoporotic bone in rabbits.METHODS The study was performed in 50 female California rabbits divided into nonovariectomized(non-OVX)and ovariectomized groups(OVX)at 6 mo of age.Rabbits were sacrificed 8 wk after the implantation of four biomaterials[TTM,CONCELOC,Zimmer Biomet's Trabecular Metal(TANTALUM),and ATLANT]in a 5-mm diameter defect created in the left femur.A biomechanical evaluation of the femur was carried out by testing implant breakout force.The force was gradually increased until complete detachment of the implant from the bone occurred.RESULTS The breakout force needed for implant detachment was significantly higher in the non-OVX group,compared with the OVX group for all implants(TANTALUM,194.7±6.1 N vs 181.3±2.8 N;P=0.005;CONCELOC,190.8±3.6 N vs 180.9±6.6 N;P=0.019;TTM,186.3±1.8 N vs 172.0 N±11.0 N;P=0.043;and ATLANT,104.9±7.0 N vs 78.9 N±4.5 N;P=0.001).In the OVX group,The breakout forces in TANTALUM,TTM,and CONCELOC did not differ significantly(P=0.066).The breakout force for ATLANT in the OVX group was lower by a factor of 2.3 compared with TANTALUM and CONCELOC,and by 2.2 compared with TTM(P=0.001).In the non-OVX group,the breakout force for ATLANT was significantly different from all other implants,with a reduction in fixation strength by a factor of 1.9(P=0.001).CONCLUSION TANTALUM,TTM,and CONCELOC had equal bone-implant osseointegration in healthy and in osteoporotic bone.ATLANT had significantly decreased osseointegration(P=0.001)in healthy and in osteoporotic bone.