The Dynamic Glenoid Track: An Updated Model of Glenohumeral Cartilage Contact During In Vivo Movement

项目总结/摘要 肩关节前不稳定是体力活动者的常见问题， 由于受伤复发率高，导致失业时间延长，因此影响很大。受伤 导致前不稳定的通常包括肱骨头（Hill-Sachs病变）和关节盂损伤 骨（骨性Bankart病变）。目前治疗前不稳定的手术指南， 骨损伤是基于测量盂肱接触区域（“关节盂 跟踪”）。基于尸体的生物力学研究 复制体内负荷，运动学和肌肉活动，因此目前的指南缺乏准确性， 在肩关节前不稳定患者中指导手术决策所需的普遍性， 亚临界（10%-20%）关节盂骨丢失。我们迫切需要更好地理解 在体内运动过程中，解剖学和运动学影响盂肱关节接触， 在这个具有挑战性的患者群体中可以确定手术治疗。本研究的目的是确定 动态关节盂轨迹，并根据 动态关节盂轨迹，用于预测三种常见手术治疗肩关节前部后的肩关节功能 不稳定在这项机械辅助研究中，动态双平面X线摄影（DBR）的体内运动学将 结合MRI的软骨形态学，测量加载期间的盂肱接触区域， 无负荷旋转和外展30°、60°、90°和120°时的外旋（动态 关节盂轨道）。将在健康对照组中测量动态关节盂轨迹，并与之前的 报告了静态关节盂轨迹。来自健康肩膀的数据将用于开发一个模型来预测 根据骨损伤的大小和位置确定患者的软骨接触和不稳定性。的有效性和 将通过在手术前测试来自母研究的患者来评价模型的稳健性。最后 患者特异性模型预测手术后软骨接触区域的能力将使用 母研究中患者的术前和术后数据。具体目的是：1）比较体内 健康肩关节的动态关节盂轨迹与先前报告的静态关节盂轨迹，2）发展和 验证用于预测动态内固定期间盂肱软骨接触的患者特异性评价过程 体内运动，以及3）确定患者特异性模型在预测动态运动中的准确性， 手术后盂肱软骨接触。实现这些目标将提供深入了解解剖 和运动学机制，导致前肩关节稳定性的丧失和恢复，并将阐明 并改善肩关节前不稳定和亚临界关节盂骨患者的手术指南 损失

Project Summary/Abstract Anterior shoulder instability is a common problem in physically active individuals and has serious long-term implications due to the high rate of injury recurrence and the resulting extended time out of work. The injury leading to anterior instability often includes damage to both the humeral head (Hill-Sachs lesion) and glenoid bone (bony Bankart lesion). The current surgical guidelines for treating anterior instability in the presence of bony lesions are based upon biomechanical studies that measured glenohumeral contact regions (the “glenoid track”) in cadaver specimens during static simulated loading. Cadaver-based biomechanical studies cannot replicate in vivo loads, kinematics, and muscle activity, and so the current guidelines lack the accuracy and generalizability needed to guide surgical decision-making in patients with anterior shoulder instability and subcritical (10% to 20%) glenoid bone loss. A critical need exists to improve our understanding of how anatomy and kinematics affect glenohumeral articular contact during in vivo movement so that the optimal surgical treatment can be identified in this challenging patient cohort. The objectives of this study are to define the dynamic glenoid track and to develop and validate a patient-specific evaluation process, based upon the dynamic glenoid track, to predict shoulder function after three common surgeries to treat anterior shoulder instability. In this mechanistic ancillary study, in vivo kinematics from dynamic biplane radiography (DBR) will be combined with cartilage morphology from MRI to measure glenohumeral contact regions during loaded and unloaded circumduction and during external rotation at 30°, 60°, 90° and 120° of abduction (the dynamic glenoid track). The dynamic glenoid track will be measured in healthy controls and compared to the previously reported static glenoid track. Data from healthy shoulders will then be used to develop a model to predict cartilage contact and instability in patients based upon bone lesion size and location. The validity and robustness of the model will be evaluated by testing patients from the parent study prior to surgery. Finally, the ability of the patient-specific models to predict cartilage contact regions after surgery will be evaluated using pre and post-surgery data from patients in the parent study. The Specific aims are: 1) to compare the in vivo dynamic glenoid track in healthy shoulders to the previously reported static glenoid track, 2) to develop and validate a patient-specific evaluation process for predicting glenohumeral cartilage contact during dynamic in vivo movement, and 3) to determine the accuracy of the patient-specific model in predicting dynamic glenohumeral cartilage contact after surgery. Achieving these objectives will provide insight into the anatomic and kinematic mechanisms that lead to the loss and restoration of anterior shoulder stability, and will clarify and improve the surgical guidelines for patients with anterior shoulder instability and subcritical glenoid bone loss.