I-Corps: Integrated Strain Sensor for Dynamic Hip Screws

I-Corps项目的广泛影响和商业潜力源于该技术在解决髋部骨折治疗关键临床空白方面的潜力。髋粗隆间骨折在老年患者中很常见，影响他们的活动能力和生活质量。他们通常使用动态髋螺钉（DHS）进行治疗，该螺钉由钛板和空心螺钉组成，将骨折的髋球固定在股骨的其余部分上，从而使骨折愈合。与大多数用于骨折固定的植入物一样，DHS不是为长期承重而设计的。如果患者的骨折在手术后没有愈合，那么DHS或骨骼就会疲劳和失效，需要进行翻修手术。这使得临床医生处于一个困难的位置，因为他们必须在手术后仔细监测患者的植入物失败的迹象。然而，当失败的迹象很明显时，通常为时已晚，无法挽救种植体，翻修手术是必要的。该设备可以提供一种定量跟踪骨折愈合的方法，使医生和患者能够改变康复方案并添加辅助治疗，以避免与灾难性植入物失败相关的发病率和死亡率。这个I-Corps项目的重点是一种帮助医生管理髋部骨折康复的新设备。该设备的独特之处在于，它可以无缝集成到现有的动态髋螺钉（DHS）系统中，并使用x线平片进行读取，x线平片在随访期间已经获得，但如果没有该传感器，则无法定量或敏感地跟踪骨折刚度。具体来说，该设备测量负重时螺钉的弯曲度：固定后，螺钉立即将股骨固定在一起，承担全部载荷，并在载荷下明显弯曲。然而，随着骨折愈合和周围骨承受更多的负荷，螺钉弯曲成比例地减少。虽然弯曲程度太小，无法从传统的x光片上精确测量，但该装置使用一根直的放射性致密钨棒穿过螺杆的空心部分，以清楚地突出位移。初步结果已经在计算机模拟、尸体标本和绵羊研究中证明了原理。测量骨折刚度很重要，因为如果骨折愈合太慢，植入物或骨头会疲劳和失效，需要昂贵和危险的翻修手术。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this I-Corps project stems from the potential of the technology to address a key clinical gap hip fracture treatment. Intertrochanteric hip fractures are common among elderly patients, affecting their mobility and quality of life. They are routinely treated with a dynamic hip screw (DHS) consisting of a titanium plate and cannulated lag screw that hold the fractured ball of the hip onto the rest of the femur so that the fracture can heal. Like most implants for fracture fixation, the DHS is not designed for long-term load bearing. If a patient's fracture does not heal after surgery, then the DHS or bone will fatigue and fail, requiring revision surgery. This leaves clinicians in a difficult position, as they must carefully monitor their patients for signs of implant failure after surgery. However, by the time signs of failure are apparent, it is often too late to salvage the implant, and a revision surgery is necessary. This device can provide a way to quantitively track fracture healing, enabling physicians and patients to alter rehabilitation protocols and add adjunctive therapies to avoid morbidity and mortality associated with catastrophic implant failure.This I-Corps project focuses on a novel device to help physicians manage hip fracture rehabilitation. The envisioned device is unique in that it can be seamlessly integrated into existing dynamic hip screw (DHS) systems and is read using plain radiography, which is already acquired during follow-up visits but is not quantitative or sensitive enough for tracking fracture stiffness without this sensor. Specifically, the device measures screw bending during weight bearing: immediately after fixation, the screw holds the femur together, carries the full load, and bends significantly under load. However, as the fracture heals and the surrounding bone carries more load, and the screw bends proportionately less. Although the degree of bending is too small to accurately measure from traditional radiographs, this device uses a straight radio-dense tungsten rod through the hollow part of the screw to clearly highlight displacement. Preliminary results have shown proof-of-principle in computer simulations, cadaveric specimens, and a sheep study. Measuring fracture stiffness is important because if the fracture heals too slowly, the implant or bone will fatigue and fail, requiring costly and risky revision surgery.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.