Lalone Emily A, Deluce Simon R, Shannon Hannah, King Graham J W, Johnson James A
Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada.
Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada; Roth/McFarlane Hand and Upper Limb Center, St. Joseph's Health Care, London, Ontario, Canada.
J Hand Surg Am. 2017 Nov;42(11):924.e1-924.e11. doi: 10.1016/j.jhsa.2017.05.028. Epub 2017 Jul 18.
The objective of this study was to characterize the morphology of the radial head and design population-based anatomical and patient-specific radial head implants.
Computed tomography (CT) images of 50 normal cadaveric upper extremities (34 male, 16 female) were obtained using a 64-slice CT scanner. Surface models were ellipse-fitted and characterized. Using an intersurface distance mapping approach, the surface geometry of the population-based anatomical design (PB-An), 3 distinct patient-specific designs, and an existing axisymmetrical implant (Com-Axi) were compared with the native radial head and the overall surface mismatch was measured.
Morphological analysis indicated that the diameters of the outer and rim ellipses were correlated. The mean mismatch for the existing commercially available axisymmetrical implants was 0.5 ± 0.1 mm.The PB-An implants showed significantly reduced surface mismatch (0.4 ± 0.2 mm). The PS-An implant using 82 parameters in its design (0.1 ± 0.0 mm), had the lowest mean surface mismatch of any of the implants investigated.
The mean surface mismatch of radial head implants may be reduced using reverse engineering techniques to determine the required parameters for both population-based and patient-specific implant designs. Whether there is a significant clinical advantage of a more anatomically shaped radial head implant requires additional study. More anatomical implant shapes rely on a surgical technique to accurately position these implants during surgery. It is unclear if this can be achieved clinically using conventional techniques or whether computer-assisted surgery will be required to realize the potential advantages of a more anatomical implant.
This study characterized the morphology of the radial head with implications for population-based anatomical implants and patient-specific implants. The overall design of each implant was quantitatively compared with the native radial head. This study has implications for the design of patient-specific/anatomical implants and compares their use with commercially available generic implants.
本研究的目的是描述桡骨头的形态，并设计基于人群的解剖型和患者特异性桡骨头植入物。
使用64层CT扫描仪获取50例正常尸体上肢（34例男性，16例女性）的计算机断层扫描（CT）图像。对表面模型进行椭圆拟合和特征描述。采用表面间距离映射方法，将基于人群的解剖设计（PB-An）、3种不同的患者特异性设计以及现有的轴对称植入物（Com-Axi）的表面几何形状与天然桡骨头进行比较，并测量整体表面不匹配度。
形态学分析表明，外侧和边缘椭圆的直径相关。现有的市售轴对称植入物的平均不匹配度为0.5±0.1毫米。PB-An植入物的表面不匹配度显著降低（0.4±0.2毫米）。在其设计中使用82个参数的PS-An植入物（0.1±0.0毫米），在所有研究的植入物中平均表面不匹配度最低。
使用逆向工程技术确定基于人群和患者特异性植入物设计所需的参数，可降低桡骨头植入物的平均表面不匹配度。更符合解剖形状的桡骨头植入物是否具有显著的临床优势需要进一步研究。更符合解剖形状的植入物形状依赖于一种手术技术，以便在手术期间准确地定位这些植入物。目前尚不清楚使用传统技术在临床上是否能够实现这一点，或者是否需要计算机辅助手术来实现更符合解剖形状的植入物的潜在优势。
本研究描述了桡骨头的形态，对基于人群的解剖植入物和患者特异性植入物具有启示意义。将每个植入物的整体设计与天然桡骨头进行了定量比较。本研究对患者特异性/解剖植入物的设计具有启示意义，并将其使用情况与市售通用植入物进行了比较。
