The effects of progressive lateralization of the joint center of rotation of reverse total shoulder implants
The effects of progressive lateralization of the joint center of rotation of reverse total shoulder implants
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DOI：
10.1016/j.jse.2014.11.040
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发表时间：
2015-07-01
影响因子：
3
通讯作者：
Gulotta, Lawrence V.
中科院分区：
文献类型：
--
作者：
Costantini, Oren;Choi, Daniel S.;Gulotta, Lawrence V.
背景：在反向肩关节置换术中使用的植入物中，有一个新的兴趣是使旋转中心（CoR）偏侧。本研究的目的是确定CoR偏侧对肩关节接触力、肌肉力矩臂、骨-种植体界面扭矩的敏感性，以及种植体的稳定性。方法：采用三维虚拟模型研究侧移对三角肌力臂和盂肱关节接触力的影响。该模型植入5个逐渐侧化的反向肩关节假体。在3次模拟的标准肱骨胸椎运动过程中，计算每次侧化时的关节接触载荷和三角力臂。结果：侧化的CoR导致增加整个关节接触力在整个盂内球。虽然也观察到前/后和上/下剪切的增加，但这种增加的载荷大部分是通过压缩发生的。三角肌的力臂随着侧化持续减少。种植体界面弯矩随侧化而增加。渐进式侧化改善了稳定性比。结论：侧化导致关节负荷增加。大部分的荷载通过压缩发生，尽管也有剪切力的增加。目前，前/后切变在种植体固定研究中未被考虑在内，因此其对种植体固定的影响尚不清楚。未来的研究应将剪切力纳入其模型，以更准确地评估固定方法。证据等级：基础科学，计算机建模。(C) 2015年《肩关节外科杂志》理事会理事。
Background: There has been a renewed interest in lateralizing the center of rotation (CoR) in implants used in reverse shoulder arthroplasty. The aim of this study was to determine the sensitivity of lateralization of the CoR on the glenohumeral joint contact forces, muscle moment arms, torque across the bone-implant interface, and the stability of the implant.Methods: A 3-dimensional virtual model was used to investigate how lateralization affects deltoid muscle moment arm and glenohumeral joint contact forces. This model was virtually implanted with 5 progressively lateralized reverse shoulder prostheses. The joint contact loads and deltoid moment arms were calculated for each lateralization over the course of 3 simulated standard humerothoracic motions.Results: Lateralization of the CoR leads to an increase in the overall joint contact forces across the glenosphere. Most of this increased loading occurred through compression, although increases in anterior/posterior and superior/inferior shear were also observed. Moment arms of the deltoid consistently decreased with lateralization. Bending moments at the implant interface increased with lateralization. Progressive lateralization resulted in improved stability ratios.Conclusions: Lateralization results in increased joint loading. Most of that loading occurs through compression, although there were also increases in shear forces. Anterior/posterior shear is currently not accounted for in implant fixation studies, leaving its effect on implant fixation unknown. Future studies should incorporate shear forces into their models to more accurately assess fixation methods.Level of evidence: Basic Science, Computer Modeling. (C) 2015 Journal of Shoulder and Elbow Surgery Board of Trustees.