Voss Andreas, Beitzel Knut, Obopilwe Elifho, Buchmann Stefan, Apostolakos John, Di Venere Jessica, Nowak Michael, Cote Mark P, Romeo Anthony A, Mazzocca Augustus D
Department of Orthopaedic Surgery, University of Connecticut, Farmington, CT, USA.
Department of Orthopaedic Sports Medicine, Technical University, Munich, Germany.
BMC Musculoskelet Disord. 2017 May 25;18(1):213. doi: 10.1186/s12891-017-1550-0.
The purpose of this study was to examine biomechanical properties and the degree of radiolucency of two cemented basic glenoid designs for total shoulder arthroplasty. Our hypothesis was that a component with increased micro-motion in the laboratory at time zero would also exhibit a greater amount of radiolucency in patients at a minimum of 2 years post total shoulder arthroplasty.
Thirty cadaveric shoulders were divided into 2 groups (keel vs. peg). The glenoid components were first loaded with a single axial eccentric force of 196 N in all orientations and then with a transversal load of 49 N to simulate in vivo loads with abduction. Displacement of the glenoid component was determined with four different linear variable-differential transducers. In the second phase, 56 antero-posterior x-rays of 52 patients with either the same keeled (n = 24) or pegged (n = 32) glenoid component with a minimum of 24 months follow-up were evaluated for radiolucency.
Biomechanically the pegged glenoid showed a significant increase in micro-motion during eccentric axial loading as well as during combined loading in the anterior, posterior, and inferior position as compared to the keeled glenoid (p < 0.05). In contrast all results were significant with greater radiolucency for the keeled glenoid component (p = 0.001).
While the pegged component exhibited a greater amount of micro-motion during biomechanical testing, radiolucency was greater in patients with a keeled component. These findings provide support for both components from different perspectives and highlight the need for well-constructed studies to determine whether glenoid design has an effect on clinical outcome, because influences are multifactorial and biomechanical forces may not recreate forces seen in vivo.
本研究的目的是检查两种用于全肩关节置换术的骨水泥固定型基本盂设计的生物力学特性和透亮程度。我们的假设是，在实验室中零时微动增加的假体组件，在全肩关节置换术后至少2年的患者中也会表现出更大程度的透亮。
30个尸体肩关节被分为2组（龙骨型与柱栓型）。首先在所有方向上对盂假体施加196 N的单一轴向偏心载荷，然后施加49 N的横向载荷以模拟外展时的体内载荷。使用四个不同的线性可变差动传感器确定盂假体的位移。在第二阶段，对52例使用相同龙骨型（n = 24）或柱栓型（n = 32）盂假体且随访至少24个月的患者的56张前后位X线片进行透亮评估。
生物力学方面，与龙骨型盂相比，柱栓型盂在偏心轴向加载以及在前、后和下位置的联合加载过程中微动显著增加（p < 0.05）。相比之下，所有结果均显示龙骨型盂假体的透亮程度更高，差异有统计学意义（p = 0.001）。
虽然柱栓型假体在生物力学测试中表现出更大程度的微动，但龙骨型假体患者的透亮程度更高。这些发现从不同角度为两种假体提供了支持，并强调需要进行精心设计的研究，以确定盂设计是否对临床结果有影响，因为影响是多因素的，生物力学力可能无法重现体内所见的力。
