Der Einfluss von Oberflächenmerkmalen auf die Primärstabilität einer zementfreien Hüftpfanne: eine mechanischeIn-vitro-Untersuchung / The influence of different surface treatments on the primary stability of cementless acetabular cups: anin vitrostudy
Authors:
- Ute SchreinerUSUte Schreiner
- Martin SimnacherMSMartin Simnacher
- Gerhard SchellerGSGerhard Scheller
- Hanns-Peter ScharfHSHanns-Peter Scharf
- 1 June 2007
- journal article
- research article
- Published by Walter de Gruyter GmbH in Biomedical Engineering / Biomedizinische Technik
- Vol. 52 (3) , 243-247
Abstract
Long-term stability of cementless acetabular cups depends on osseointegration, which requires primary stability of the implant. The aim of this study was to determine the influence of different surface treatments on the primary stability of press-fit acetabular cups. Mechanical lever-out tests were performed to quantify the stability in vitro. A hemispherical press-fit cup design with a flattened pole was used and different surface modifications were applied: smooth, corundum-blasted, titanium plasma spray, rough titan plasma spray, and titanium plasma spray with a rim. The outer diameter of all cups was kept constant. Polyurethane foam was selected as the test material and cup insertion was performed with a maximal force of 6000 N. The excess length between the cup and the surface of the foam blocks was measured. The maximum lever-out force was measured and the lever-out torque was calculated. The excess length of cups with a smooth surface was significantly less (p<0.001) than for the other cups, with no significant differences among the other surface modifications. The lever-out torque for cups with a smooth surface was significantly less (p<0.001) than for the other cups, with no significant differences among the other surface modifications. Only the cup with a smooth surface showed significant differences for excess length and lever-out torque. The other surface modifications exhibited the same stability. As long as a rough surface is chosen, cup design seems to have a greater influence on stability than surface modification. Although the study did not mimic real in vivo conditions and the lever-out-torques cannot be transferred to clinical situations, initial stability before bony ingrowth occurred could be clearly analysed.Keywords
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