Relative motion at the taper junction of modular hip prostheses at the head-neck interface
H. Haschke, M.M. Morlock, G. Huber
Modular hip arthroplasty prostheses allow adaptation to the individual patient anatomy and the combination of different materials. However, modularity introduces an additional interface, which bears the risk of incorrect assembly and may be related to clinical issues. Relative motion at the taper interface might increase the overall risk for fretting, corrosion, metallic debris and early failure. The aim of the study was the quantification of relative motion within the head-neck interface.
Experimental tests include load application by a servohydraulic test machine to simulate load scenarios for realistic joint friction moments. Eddy current sensors are used to measure the relative motion between the components of the prosthesis in six degrees of freedom.
The experiments show that relative motion can reach several microns. The direction and amount of relative motion depends on the load scenario, assembly condition, material combination and prosthesis type.
Based on the findings so far, thoroughly cleaning of the interface is strongly advised. Inside into the failure mechanism and the influencing factors might help to prevent implant failures in the future.
Haschke H., Jauch S.Y., Huber G., Baxmann M., Grupp T.M., Morlock M.M. (2011). Werden Relativbewegungen an der Konusverbindung einer modularen Hüftendoprothese von Fügekraft und Konuswinkel beeinflusst? Jahrestagung der Deutschen Gesellschaft für Biomechanik.
Haschke H., Bishop N., Witt F., Eicke Y., Morlock M.M. (2015). Contamination of Modular Hip Taper Interfaces Increases Post-Assembly Interface Seating Annual Congress of the International Society for Technology in Arthroplasty (ISTA).
Haschke H., Huber G., Morlock M.M. (2015). Eindringen von Flüssigkeiten in die Konusverbindung modularer Hüftendoprothesen. Jahrestagung der Deutschen Gesellschaft für Biomechanik.
Haschke H., Eicke Y., Huber G., Morlock M.M. (2016). The Influence of Contamination and Assembly Load on the Micromotion at the Head-Stem Taper. Congress of the European Society of Biomechanics.