Department of Orthopedics and Trauma Surgery, Medical University of Vienna, 1090 Vienna, Austria.
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria.
Medicina (Kaunas). 2023 Feb 22;59(3):429. doi: 10.3390/medicina59030429.
: The treatment of transfemoral amputees using osseointegrated implants for prosthetic anchorage requires accurate implant positioning when using threaded bone-anchoring implants due to the curvature of the femur and the risk of cortical penetration in misaligned implants. This study investigated the accuracy and precision in implant positioning using additively manufactured case-specific positioning guides. : The geometry and density distribution of twenty anatomic specimens of human femora were assessed in quantitative computed tomography (QCT) scanning. The imaging series were used to create digital 3D specimen models, preoperatively plan the optimal implant position and manufacture specimen-specific positioning guides. Following the surgical bone preparation and insertion of the fixture (threaded bone-anchoring element) (OPRA; Integrum AB, Mölndal, Sweden), a second QCT imaging series and 3D model design were conducted to assess the operatively achieved implant position. The 3D models were registered and the deviations of the intraoperatively achieved implant position from the preoperatively planned implant position were analyzed as follows. The achieved, compared to the planned implant position, was presented as resulting mean hip abduction or adduction (A/A) and extension or flexion (E/F) and mean implant axis offset in medial or lateral (M/L) and anterior or posterior (A/P) direction measured at the most distal implant axis point. : The achieved implant position deviated from the preoperative plan by 0.33 ± 0.33° (A/A) and 0.68 ± 0.66° (E/F) and 0.62 ± 0.55 mm (M/L) and 0.68 ± 0.56 mm (A/P), respectively. : Using case-specific guides, it was feasible to achieve not only accurate but also precise positioning of the implants compared to the preoperative plan. Thus, their design and application in the clinical routine should be considered, especially in absence of viable alternatives.
: 对于经股截肢患者，使用骨整合植入物进行假体锚固的治疗需要在使用螺纹骨锚固植入物时准确放置植入物，因为股骨的弯曲以及植入物未对准时皮质穿透的风险。本研究调查了使用增材制造的特定病例定位引导器在植入物定位中的准确性和精度。 : 使用定量 CT（QCT）扫描评估了二十个人体股骨解剖标本的几何形状和密度分布。使用成像系列创建了数字 3D 标本模型，术前规划最佳植入物位置并制造标本特异性定位引导器。在手术骨准备和固定器（螺纹骨锚固元件）（OPRA；Integrum AB，Mölndal，瑞典）插入后，进行了第二次 QCT 成像系列和 3D 模型设计，以评估手术中获得的植入物位置。对 3D 模型进行了注册，并分析了术中获得的植入物位置与术前规划的植入物位置之间的偏差。将获得的植入物位置与计划的植入物位置进行比较，以髋关节外展或内收（A/A）和伸展或屈曲（E/F）的差值以及在最远端植入物轴点处测量的内侧或外侧（M/L）和前或后（A/P）方向的植入物轴偏移的平均值表示。 : 与术前计划相比，实际植入物位置的偏差为 0.33±0.33°（A/A）和 0.68±0.66°（E/F）以及 0.62±0.55mm（M/L）和 0.68±0.56mm（A/P）。 : 使用特定病例的引导器，不仅可以实现植入物的精确定位，而且可以实现与术前计划相比的精确定位。因此，应考虑在临床常规中设计和应用它们，特别是在没有可行替代方案的情况下。
