An upgraded optical coordinate measurement machine for the dimensional analysis of complex geometric devices

由于自然科学和工程学的进步，缓解疼痛和恢复功能的人工关节已经成为现实。不幸的是，关节置换手术后的早期失败和患者对结果的不满约为5%-20%。一个主要的限制是产生金属和塑料磨损颗粒的植入部件的磨损和腐蚀。这些摩擦学和化学现象会导致生物反应，包括骨吸收、种植体松动和软组织损伤，降低设备的寿命，需要进行翻修手术来更换失败的植入物。磨损和腐蚀可能会受到植入物设计、手术技术和患者因素的影响，例如体重和某些疾病。了解和/或优化这些因素以支持更长的设备寿命，需要准确测量由于磨损和腐蚀引起的尺寸变化，从而量化植入物的性能。材料损失几十微米量级的尺寸变化可能足以引起患者的金属过敏症和故障，因此需要高灵敏度的设备。我们拥有加拿大第一台光学坐标测量机，专门用于对球形髋关节植入物部件进行此类尺寸测量，例如头颈部锥形接头或髋臼杯，这两种部件通常与磨损和腐蚀有关。然而，越来越多的证据表明，其他类型的植入物也发生了磨损和腐蚀，包括膝盖、肩膀和脊柱，导致早期失败。为了能够分析这些缺乏旋转对称性的其他类型的组件，我们需要对我们的光学坐标测量机进行升级，增加一个额外的传感器，以便我们可以扫描更复杂、不对称的几何图形。这样的升级将使我们能够立即开始分析在我们机构收集的所有失败并从患者身上取出的5,500个髋关节、膝盖和肩部植入物。另一个好处是，升级后的系统将能够更好地扫描非骨科部件，使我们能够与其他需要重建复杂表面几何形状的用户共享该系统。在我们的研究项目中，测量回收的种植部件的尺寸变化将使我们能够客观地确定哪些因素与更大的磨损或腐蚀有关。我们可以利用这一新知识来帮助设计更好、更持久的植入物，让临床医生了解市场上不同设备的最佳选择，并开发腐蚀和金属过敏反应测试。

Artificial joints that alleviate pain and restore function have become a reality due to advances in the natural sciences and engineering. Unfortunately, early failures and patient dissatisfaction with outcomes after joint replacement surgery are on the order of 5-20%. A major limitation is wear and corrosion of implant components generating metal and plastic wear particles. These tribological and chemical phenomena can cause biological reactions including bone resorption, implant loosening, and soft tissue damage, reducing the longevity of the device and necessitating a revision surgery to replace the failed implant. Wear and corrosion can be affected by implant design, surgical technique, and patient factors, such as weight and certain diseases. Understanding and/or optimizing these factors to support greater device longevity requires accurate measurement of dimensional changes due to wear and corrosion, thereby quantifying implant performance. Dimensional changes due to material loss on the order of tens of microns may be sufficient to generate metal hypersensitivity and failure in patients, therefore highly sensitive equipment is required. We have Canada's first optical coordinate measuring machine optimized for performing these types of dimensional measurements on spherical hip implant components, such as the head-neck taper junction or acetabular cup, two components commonly associated with wear and corrosion. However, growing evidence suggests wear and corrosion is occurring in other types of implants including the knee, shoulder, and spine causing early failures. To be able to analyze these other kinds of components that lack rotational symmetry, we require an upgrade to our optical coordinate measuring machine by adding an additional sensor so that we can scan more complex, asymmetrical geometries. Such an upgrade will allow us to immediately start analyzing all the >5,500 hip, knee, and shoulder implants collected at our institution that have failed and been removed from patients. An additional benefit is that the upgraded system will better enable scanning of non-orthopaedic components, allowing us to share the system with other users with a need to reconstruct complex surface geometries. Measuring the dimensional changes to the retrieved implant components in our research projects will allow us to objectively determine which factors are associated with greater wear or corrosion. We can use this new knowledge to help design better, longer lasting implants, to inform clinicians about the best choices across different devices on the market, and to develop tests for corrosion and metal hypersensitivity reactions.