Biodegradable magnesium is a highly desired material for fracture fixation implants because of its good me-chanical properties and ability to completely dissolve in the body over time,eliminating the need for a second...Biodegradable magnesium is a highly desired material for fracture fixation implants because of its good me-chanical properties and ability to completely dissolve in the body over time,eliminating the need for a secondary surgery to remove the implant.Despite extensive research on these materials,there remains a dearth of infor-mation regarding critical factors that affect implant performance in clinical applications,such as the in vivo pH and mechanical loading conditions.We developed a measurement system with implantable strain,temperature,pH and motion sensors to characterize magnesium and titanium plates,fixating bilateral zygomatic arch osteotomies in three Swiss alpine sheep for eight weeks.pH 1-2 mm above titanium plates was 6.6±0.4,while for magnesium plates it was slightly elevated to 7.4±0.8.Strains on magnesium plates were higher than on titanium plates,possibly due to the lower Young’s modulus of magnesium.One magnesium plate experienced excessive loading,which led to plate failure within 31 h.This is,to our knowledge,the first in vivo strain,temperature,and pH data recorded for magnesium implants used for fracture fixation.These results provide insight into magnesium degradation and its influence on the in vivo environment,and may help to improve material and implant design for future clinical applications.展开更多
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
基金supported by the Swiss National Science Foundation via an SNF Sinergia Grant(grant number CRSII5-180367).
文摘Biodegradable magnesium is a highly desired material for fracture fixation implants because of its good me-chanical properties and ability to completely dissolve in the body over time,eliminating the need for a secondary surgery to remove the implant.Despite extensive research on these materials,there remains a dearth of infor-mation regarding critical factors that affect implant performance in clinical applications,such as the in vivo pH and mechanical loading conditions.We developed a measurement system with implantable strain,temperature,pH and motion sensors to characterize magnesium and titanium plates,fixating bilateral zygomatic arch osteotomies in three Swiss alpine sheep for eight weeks.pH 1-2 mm above titanium plates was 6.6±0.4,while for magnesium plates it was slightly elevated to 7.4±0.8.Strains on magnesium plates were higher than on titanium plates,possibly due to the lower Young’s modulus of magnesium.One magnesium plate experienced excessive loading,which led to plate failure within 31 h.This is,to our knowledge,the first in vivo strain,temperature,and pH data recorded for magnesium implants used for fracture fixation.These results provide insight into magnesium degradation and its influence on the in vivo environment,and may help to improve material and implant design for future clinical applications.
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.
