Magnesium alloys present a compelling prospect for absorbable implant materials in orthopedic and trauma surgery.This study evaluates an ultra-high purity,lean magnesium-calcium alloy(X0),both with and without plasma ...Magnesium alloys present a compelling prospect for absorbable implant materials in orthopedic and trauma surgery.This study evaluates an ultra-high purity,lean magnesium-calcium alloy(X0),both with and without plasma electrolytic oxidation(PEO)surface modification,in comparison to a clinically utilized WE43 magnesium alloy.It is shown that the mechanical properties of X0 can be tuned to yield a high-strength material suitable for bone screws(with an ultimate tensile strength of 336 MPa)or a ductile material appropriate for intraoperatively deformable plates(with an elongation at fracture of 24%).Four plate-screw combinations were implanted onto the pelvic bones of six sheep without osteotomy for 8 weeks.Subsequent analysis utilized histology,micro-computed tomography,and light and electron microscopy.All implants exhibited signs of degradation and hydrogen-gas evolution,with PEO-coated X0 implants demonstrating the least volume loss and the most sub-stantial new-bone formation on the implant surface and surrounding cancellous bone.Furthermore,the osteo-conductive properties of the X0 implants,when uncoated,exceeded those of the uncoated WE43 implants,as evidenced by greater new-bone formation on the surface.This osteoconductivity was amplified with PEO surface modification,which mitigated gas evolution and enhanced osseointegration,encouraging bone apposition in the cancellous bone vicinity.These findings thus indicate that PEO-coated X0 implants hold substantial promise as a biocompatible and absorbable implant material.展开更多
文摘Magnesium alloys present a compelling prospect for absorbable implant materials in orthopedic and trauma surgery.This study evaluates an ultra-high purity,lean magnesium-calcium alloy(X0),both with and without plasma electrolytic oxidation(PEO)surface modification,in comparison to a clinically utilized WE43 magnesium alloy.It is shown that the mechanical properties of X0 can be tuned to yield a high-strength material suitable for bone screws(with an ultimate tensile strength of 336 MPa)or a ductile material appropriate for intraoperatively deformable plates(with an elongation at fracture of 24%).Four plate-screw combinations were implanted onto the pelvic bones of six sheep without osteotomy for 8 weeks.Subsequent analysis utilized histology,micro-computed tomography,and light and electron microscopy.All implants exhibited signs of degradation and hydrogen-gas evolution,with PEO-coated X0 implants demonstrating the least volume loss and the most sub-stantial new-bone formation on the implant surface and surrounding cancellous bone.Furthermore,the osteo-conductive properties of the X0 implants,when uncoated,exceeded those of the uncoated WE43 implants,as evidenced by greater new-bone formation on the surface.This osteoconductivity was amplified with PEO surface modification,which mitigated gas evolution and enhanced osseointegration,encouraging bone apposition in the cancellous bone vicinity.These findings thus indicate that PEO-coated X0 implants hold substantial promise as a biocompatible and absorbable implant material.
