Laboratory of Biomechanics and Implant Research, Clinic for Orthopedics and Trauma Surgery, Heidelberg University Hospital, Schlierbacher Landstraße 200a, 69118 Heidelberg, Germany.
Department of Orthopedics, Kepler University Hospital, Krankenhausstraße 9, 4021 Linz, Austria.
Acta Biomater. 2019 Oct 1;97:239-246. doi: 10.1016/j.actbio.2019.07.050. Epub 2019 Jul 30.
In total hip arthroplasty, osteolysis of the acetabulum often occurs at the backside of cups in the area of screw holes, indicating a clinically relevant amount of polyethylene (PE) wear particles in this area. In order to avoid a possible migration of wear particles to the acetabulum-bone, screw hole plugs are provided for some implant systems. The aims of this study were to quantitatively determine backside wear and to investigate the migration behaviour of articulation-related wear particles in a cup system with open and closed screw holes by plugs. Titanium cup systems with backside holes for screw fixations were sinusoidally loaded with 2.7 kN. The articulation area was separated from the backside area of the cup. A defined amount of articulation-generated particles was added to the fluid of the articulation chamber. The fluids in the two chambers were separately filtered after 2 × 10 cycles for a particle analysis. Backside wear with noticeably small (65.6 ± 4.2 nm) and round PE particles was identified. With both open and closed screw holes, a migration of the articulating wear particles from the articulation area behind the cup could be observed. Backside wear was estimated to be below 1% of the articulated wear. Screw hole plugs did not effectively prevent the migration of PE wear particles behind the investigated cups. STATEMENT OF SIGNIFICANCE: Backside wear occurs in a proven cup-system. Furthermore, it was quantitatively observed that articulation-generated wear products could migrate from the articulating area along the cup/liner-interface through the screw holes behind the cup. An almost unimpeded particle migration to the acetabulum-bone, in conjunction with very small backside wear particles, could produce a clinically relevant amount of PE with respect to pelvic lysis. These findings highlight the importance of management to avoid particle migration in artificial hip cups. Therefore, primarily the use of screw hole plugs, as far as available for the respective cup-system, is recommended. The aim of avoiding particle migration by plugs, but also by using a sophisticated anchoring mechanism between cup and PE liner should continue in future.
在全髋关节置换术中，髋臼杯的后侧面在螺钉孔区域经常发生骨溶解，表明该区域存在大量临床相关的聚乙烯（PE）磨损颗粒。为了避免磨损颗粒可能迁移到髋臼骨，一些植入物系统提供了螺钉孔塞。本研究的目的是定量确定后侧面磨损，并通过塞子研究具有开放和封闭螺钉孔的杯系统中关节相关磨损颗粒的迁移行为。具有用于螺钉固定的后侧面孔的钛杯系统以 2.7 kN 的正弦载荷加载。关节区域与杯的后侧面区域分离。将一定量的关节产生的颗粒添加到关节腔的流体中。在 2×10 个循环后，将两个腔室中的流体分别过滤以进行颗粒分析。后侧面磨损产生明显较小（65.6±4.2nm）且呈圆形的 PE 颗粒。无论是开放还是封闭的螺钉孔，都可以观察到关节磨损颗粒从杯后关节区域的迁移。后侧面磨损估计为关节磨损的 1%以下。螺钉孔塞并不能有效地防止研究中的杯子后面的 PE 磨损颗粒的迁移。意义声明：在经过验证的杯子系统中会发生后侧面磨损。此外，还定量观察到关节产生的磨损产物可以从关节区域通过杯/衬里界面迁移通过杯后的螺钉孔。几乎无障碍的颗粒迁移到髋臼骨，结合非常小的后侧面磨损颗粒，可能会导致与骨盆溶解相关的大量 PE。这些发现强调了管理的重要性，以避免人工髋关节杯中的颗粒迁移。因此，原则上建议尽可能使用螺钉孔塞（只要相应的杯子系统可用）。避免颗粒迁移的目的是通过塞子，也可以通过杯和 PE 衬里之间复杂的锚固机制来实现，这在未来应继续进行。
