Department of Mechanical and Aerospace Engineering, College of Engineering Design and Physical Sciences, Brunel University, Kingston Lane, Uxbridge UB8 3PH, UK.
Sport, Health & Exercise Sciences, College of Health, Medicine and Life Sciences, Brunel University, Kingston Lane, Uxbridge UB8 3PH, UK.
Sensors (Basel). 2021 Dec 16;21(24):8405. doi: 10.3390/s21248405.
The fit of a lower limb prosthetic socket is critical for user comfort and the quality of life of lower limb amputees. Sockets are conventionally produced using hand-crafted patient-based casting techniques. Modern digital techniques offer a host of advantages to the process and ultimately lead to improving the lives of amputees. However, commercially available scanning equipment required is often expensive and proprietary. Smartphone photogrammetry could offer a low cost alternative, but there is no widely accepted imaging technique for prosthetic socket digitisation. Therefore, this paper aims to determine an optimal imaging technique for whole socket photogrammetry and evaluate the resultant scan measurement accuracy. A 3D printed transtibial socket was produced to create digital and physical twins, as reference models. The printed socket was photographed from 360 positions and simplified genetic algorithms were used to design a series of experiments, whereby a collection of photos were processed using Autodesk ReCap. The most fit technique was used to assess accuracy. The accuracy of the socket wall volume, surface area and height were 61.63%, 99.61% and 99.90%, respectively, when compared to the digital reference model. The scanned model had a wall thickness ranging from 2.075 mm at the top to 7.758 mm towards the base of the socket, compared to a consistent thickness of 2.025 mm in the control model. The technique selected did not show sufficient accuracy for clinical application due to the degradation of accuracy nearer to the base of the socket interior. However, using an internal wall thickness estimation, scans may be of sufficient accuracy for clinical use; assuming a uniform wall thickness.
下肢假肢接受腔的适配对于使用者的舒适性和下肢截肢者的生活质量至关重要。接受腔通常采用手工制作的基于患者的铸造技术来生产。现代数字技术为该过程提供了诸多优势，最终使截肢者受益。然而，商业上可用的扫描设备通常价格昂贵且专有的。智能手机摄影测量技术可能提供一种低成本的替代方案，但目前还没有被广泛接受的用于假肢接受腔数字化的成像技术。因此，本文旨在确定用于整个接受腔摄影测量的最佳成像技术，并评估由此产生的扫描测量精度。制作了一个 3D 打印的胫骨假肢接受腔，以创建数字和物理双胞胎作为参考模型。从 360 个位置拍摄打印接受腔的照片，并使用简化的遗传算法设计了一系列实验，其中使用 Autodesk ReCap 处理了一组照片。使用最适合的技术来评估准确性。与数字参考模型相比，接受腔壁体积、表面积和高度的测量精度分别为 61.63%、99.61%和 99.90%。扫描模型的壁厚从接受腔顶部的 2.075 毫米到底部逐渐增加到 7.758 毫米，而对照模型的壁厚保持一致为 2.025 毫米。由于靠近接受腔内部底部的精度降低，所选技术的精度不足以满足临床应用的要求。然而，通过使用内部壁厚估计，在假设均匀壁厚的情况下，扫描结果可能具有足够的临床应用精度。
