Banci Lorenzo, Meoli Alessio, Hintner Martin, Bloch Hans Rudolf
Permedica S.p.A., Merate, Italy.
Endolab Mechanical Engineering GmbH, Rosenheim, Germany.
Shoulder Elbow. 2020 Dec;12(1 Suppl):40-52. doi: 10.1177/1758573219826531. Epub 2019 Feb 7.
Glenoid component failures still represent the most common complication in total shoulder arthroplasty. These failures depend on several factors, including ultra-high molecular weight polyethylene (UHMWPE) wear. One reason for UHMWPE wear in total shoulder arthroplasty may be the current use of a spherical prosthetic humeral head against a radially mismatched UHMWPE glenoid component, which leads to reduced glenohumeral translations, glenoid edge loading and high translational forces during shoulder motions. The aim of this study was to assess the in vitro wear of an anatomic total shoulder prosthesis with non-spherical non-conforming bearings with inverted conventional materials.
The wear of a vitamin E-blended UHMWPE non-spherical humeral head articulating against a non-conforming titanium-niobium nitride (TiNbN)-coated metallic glenoid was tested using a joint simulator. The wear test was performed by applying a constant load of 756 N with angular motions and translations.
After 2.5 million cycles, the mean wear rate of the humeral head was 0.28 ± standard deviation (SD) 0.45 mg/million cycles.
The low wear rate of the vitamin E UHMWPE humeral head supports the use of non-spherical non-conforming bearings with inverted conventional materials in anatomic total shoulder arthroplasty.
盂肱关节组件失败仍是全肩关节置换术中最常见的并发症。这些失败取决于多种因素，包括超高分子量聚乙烯（UHMWPE）磨损。全肩关节置换术中UHMWPE磨损的一个原因可能是目前使用球形人工肱骨头与径向不匹配的UHMWPE盂肱关节组件，这会导致盂肱关节平移减少、盂缘负荷增加以及肩部运动期间的高平移力。本研究的目的是评估采用非球形非匹配轴承且材料与传统材料相反的解剖型全肩关节假体的体外磨损情况。
使用关节模拟器测试了掺有维生素E的UHMWPE非球形肱骨头与非匹配的氮化钛铌（TiNbN）涂层金属盂肱关节之间的磨损情况。磨损测试通过施加756 N的恒定负荷并进行角向运动和平移来进行。
在250万次循环后，肱骨头的平均磨损率为0.28±标准差（SD）0.45 mg/百万次循环。
维生素E UHMWPE肱骨头的低磨损率支持在解剖型全肩关节置换术中使用非球形非匹配轴承且材料与传统材料相反的设计。
