Data underlying MSc thesis: Design of a Distal Radius Fracture Immobilisation Device

Immobilisation devices are commonly used for the treatment of extra-articular distal radius fractures. However, conventional immobilisation devices such as plaster casts and fibreglass casts may lead to complications and discomfort. Another disadvantage of present-day conservative fracture treatment is that the casts have to be replaced after one or two weeks when the swelling subsides. In this thesis, an alternative distal radius fracture treatment device was designed, prototyped and evaluated. The main goal of this design was to make the immobilisation device adaptable to swelling while fitting most patients. <br>The device was designed using a three-step iterative design process and four successive iterations. The steps that were performed in each iteration were setting the requirements, generating solutions and evaluating and deciding. The development of the design was done in the following steps: generating design directions, developing a conceptual design, embodiment of the design and detailing the design. A prototype of the device was created to demonstrate the device's functionality. The design and the prototype were evaluated using diverse methods. Ten healthy volunteers provided feedback after wearing the device, an orthopaedic surgeon offered his expert opinion and several aspects were assessed using calculations and literature. After the prototype was made and evaluated with healthy participants an additional iteration was done to improve the function of the design.<br>In the first stage, 16 design directions were generated, and the three most promising design directions, the Cushioned Clamp, the Filled Sleeve and the Friction Slots were selected. In the next stage, these design directions were further developed into conceptual designs. The Cushioned Clamp was chosen as the best solution. The Cushioned Clamp consists of interconnected rings around the forearm, wrist and hand with pads that can be adapted in height. In the next step, an embodied design was made. This design had a large offset on the arm and therefore the rings were made adjustable during the detailing phase. Also, the usability of the device was improved. The final design is a device with three adjustable rings with pads that can separately be adjusted for swelling of the limb. The rings are connected with telescopic mechanisms. With a few additional size parts, the single immobilisation device can be adapted to fit 90\% of the adult population. The device was prototyped using aluminium, SLA-printed Form Tough 1500 and Draft Resin, FDM-printed PLA and foam. The prototype allowed too much movement of the wrist, this was addressed and solved after the tests with healthy volunteers. The device is reusable, which reduces waste as less material is used and disposed of. Furthermore, the device is waterproof which reduces skin complications and improves hygiene. The device allows thumb movement which improves the hand function. Furthermore, the mass of the device is 437~grams, which is less than a conventional plaster cast. Volunteers were generally satisfied with the device and the device is quick in application. The medical experts shared concerns about comfort, robustness and applicability for different fracture types. During the improvement phase, several aspects of the device were discussed and improvements were made. Most importantly, additional telescopic mechanisms and connections were designed to prevent movement in the device. Further, the comfort, X-ray permeability and play in the prototype were addressed. <br>The device is adjustable and adaptable to swelling while allowing skin ventilation. Further, good hand function, a sustainable design and clean applications are advantages of this design. However, the functionality of the design and the prototype can be improved by reducing play and improving robustness. Furthermore, the comfort of the device can be increased by making the device more compact and distributing the pressure better.

固定装置（Immobilisation device）常被用于治疗桡骨远端关节外骨折（extra-articular distal radius fractures）。然而，传统固定装置如石膏绷带（plaster casts）与纤维石膏绷带（fibreglass casts）易引发并发症，且佩戴舒适度欠佳。当前保守骨折治疗（conservative fracture treatment）的另一弊端在于，当肿胀消退后，需在1至2周内更换绷带。本研究设计、制作原型机（prototype）并评估了一款新型桡骨远端骨折治疗装置，其核心设计目标为：在适配多数患者的同时，可随肢体肿胀进行调节。<br>该装置采用三步迭代设计流程（three-step iterative design process）与四轮连续迭代完成设计，每一轮迭代均包含需求设定、方案生成、评估与决策四个环节。整体设计开发分为以下步骤：确立设计方向、构建概念设计（conceptual design）、完成结构具体化设计（embodiment of the design）与细节优化（detailing the design）。本研究制作了装置原型以验证其功能，并通过多种方法对设计方案与原型机进行评估：招募10名健康志愿者佩戴装置并反馈使用体验，邀请骨科医生（orthopaedic surgeon）提供专业意见，同时通过计算与文献调研对多项性能指标进行评估。在完成原型制作并经健康受试者评估后，本研究额外开展一轮迭代以优化装置功能。<br>第一阶段共生成16项设计方向，最终筛选出三项最具潜力的方案：缓冲夹钳式（Cushioned Clamp）、填充套筒式（Filled Sleeve）与摩擦槽式（Friction Slots）。第二阶段将这三项方案进一步细化为概念设计，最终选定缓冲夹钳式作为最优方案。该方案由环绕前臂、腕部与手部的互连环体构成，环体配备可调节高度的衬垫。后续阶段完成了结构具体化设计，但初始设计在手臂处存在较大偏移，因此在细节优化阶段将环体设计为可调节结构，同时提升了装置的使用便利性。最终设计方案包含三个可调节环体，每个环体的衬垫均可独立调节以适配肢体肿胀，环体之间通过伸缩机构（telescopic mechanisms）连接。搭配少量额外尺寸适配部件，该固定式装置可适配90%的成年人群。<br>本研究采用多种材料制作原型机，包括铝合金、光固化立体打印（SLA）成型的Form Tough 1500与Draft Resin，以及熔融沉积建模（FDM）打印的聚乳酸（PLA）与泡沫材料。初始原型存在腕部活动度过大的问题，经健康志愿者测试后，该问题得到解决。该装置可重复使用，减少了材料消耗与废弃物产生，具备环保优势；同时装置防水，可降低皮肤并发症风险并提升卫生水平。装置允许拇指活动，有助于维持手部功能；其总质量约为437克，轻于传统石膏绷带。志愿者对该装置整体满意度较高，且装置穿戴便捷。不过，医学专家对装置的舒适度、耐用性以及适配不同骨折类型的适用性提出了担忧。在优化阶段，本研究针对装置的多项性能展开讨论并实施改进：最核心的改进为新增伸缩机构与连接结构，以抑制装置内的多余活动；此外，还针对舒适度、X射线透过性（X-ray permeability）以及原型的间隙量进行了优化。<br>该装置具备可调节性，可适配肢体肿胀，同时支持皮肤透气。此外，良好的手部功能保留、可持续设计与便捷清洁是本设计的优势。不过，仍可通过减少间隙量与提升耐用性进一步优化设计与原型的功能；同时，可通过缩小装置体积与优化压力分布，进一步提升装置的佩戴舒适度。