Does Surface Topography Play a Role in Taper Damage in Head-neck Modular Junctions?

Area of Science:

• Biomaterials Engineering
• Orthopedic Surgery
• Tribocorrosion

Background:

• Modular taper junctions in total hip arthroplasty are prone to corrosion failure.
• Machining marks on taper surfaces create a micro-scale topography.
• The influence of this topography on fretting and corrosion is not fully understood.

Purpose of the Study:

• Compare damage scores and surface topography between CoCr/CoCr and CoCr/Ti modular junctions.
• Investigate the relationship between surface topography, material properties, and damage in CoCr/CoCr couples.
• Examine how surface topography, material properties, and time influence damage in CoCr/Ti couples.

Main Methods:

• Evaluated damage using a modified Goldberg score in 140 CoCr/CoCr and 129 CoCr/Ti retrieved hip implants.
• Measured stem taper machining mark height/spacing and head taper roughness using white light interferometry.
• Assessed taper angle mismatch and flexural rigidity; analyzed relationships with damage scores via multiple regression.

Main Results:

• CoCr/CoCr junctions showed less mild and more severe stem taper damage than CoCr/Ti.
• Higher stem taper machining mark heights were linked to lower stem taper damage in CoCr/CoCr couples.
• Head taper roughness correlated with higher damage scores in CoCr/Ti couples, while time in situ increased damage in CoCr/CoCr.

Conclusions:

• Stem taper surface topography impacts damage scores in retrieved modular junctions, with differing effects between CoCr/CoCr and CoCr/Ti couples.
• Taper topography with higher machining peaks may slow damage progression and reduce corrosion product release, benefiting implant design.