Department of Imaging Diagnostic, Hospital Israelita Albert Einstein, São Paulo, Brazil.
Musculoskeletal Radiology, Instituto de Ortopedia e Traumatologia, Hospital das Clínicas HCFMUSP, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
Am J Sports Med. 2023 Mar;51(4):985-996. doi: 10.1177/03635465231153144. Epub 2023 Feb 15.
Syndesmotic injury in an athletic population is associated with a prolonged ankle disability after an ankle sprain and often requires a longer recovery than a lateral collateral ligament injury. Although several imaging tests are available, diagnosing syndesmotic instability remains challenging.
To determine the diagnostic accuracy of conventional ankle computed tomography (CT) scans with the joint in external rotation and dorsiflexion and compare it with that of conventional ankle CT scans in a neutral position.
Cohort study (Diagnosis); Level of evidence, 2.
Between September 2018 and April 2021, this prospective study consecutively included adults visiting the foot and ankle outpatient clinic with a positive orthopaedic examination for acute syndesmotic injury. Participants underwent 3 CT scan tests. First, ankles were scanned in a neutral position. Second, ankles were scanned with 45° of external rotation, dorsiflexion, and extended knees. Third, ankles were scanned with 45° of external rotation, dorsiflexion, and flexed knees. Three measurements, comprising rotation (measurement ), lateral translation (measurement ), and anteroposterior translation (measurement ) of the fibula concerning the tibia, were used to diagnose syndesmotic instability in the 3 CT scans. Magnetic resonance imaging was used as a reference standard. The area under the curve (AUC) was used to compare the diagnostic accuracy, and Youden's J index was calculated to determine the ideal cutoff point.
Images obtained in 68 participants (mean age, 36.5 years; range, 18-69 years) were analyzed, comprising 36 syndesmotic injuries and 32 lateral collateral ligament injuries. The best diagnostic accuracy occurred with the rotational measurement , in which the second and third CT scans with stress maneuvers presented greater AUCs (0.97 and 0.99) than did the first CT scan in a neutral position (0.62). The ideal cutoff point for the stress maneuvers was 1.0 mm in the rotational measurement and reached a sensitivity and specificity of 83% and 97% for the second CT scan with extended knees and 86% and 100% for the third CT scan with flexed knees, respectively. The ideal cutoff point for the first CT scan with a neutral position was 0.7 mm in the rotational measurement , with a sensitivity of 25% and specificity of 97%.
Conventional ankle CT with stress maneuvers has excellent performance for diagnosing subtle syndesmotic rotational instability, as it shows a greater AUC and enhanced sensitivity at the ideal cutoff point compared with ankle CT in the neutral position.
在运动人群中，踝关节联合损伤与踝关节扭伤后长期踝关节功能障碍有关，且通常需要比外侧副韧带损伤更长的康复时间。尽管有几种影像学检查可供选择，但诊断踝关节联合不稳定仍然具有挑战性。
评估外旋和背屈位下常规踝关节 CT 扫描在诊断踝关节联合不稳定中的诊断准确性，并与中立位下常规踝关节 CT 扫描进行比较。
队列研究（诊断）；证据等级，2 级。
本前瞻性研究于 2018 年 9 月至 2021 年 4 月间连续纳入在足踝门诊就诊的急性踝关节联合损伤患者，体格检查阳性。参与者接受了 3 次 CT 扫描检查。首先，踝关节处于中立位进行扫描。其次，踝关节在外旋 45°、背屈和伸膝位下进行扫描。第三，踝关节在外旋 45°、背屈和屈膝位下进行扫描。在 3 次 CT 扫描中，使用测量旋转、测量外侧平移和测量前后平移这 3 个测量值来诊断踝关节联合不稳定，以磁共振成像作为参考标准。采用曲线下面积（AUC）比较诊断准确性，计算约登指数确定理想的截断点。
共分析了 68 名参与者（平均年龄 36.5 岁；范围 18-69 岁）的图像，其中 36 例为踝关节联合损伤，32 例为外侧副韧带损伤。在旋转测量中，第二次和第三次 CT 扫描的诊断准确性最佳，压力试验下的 AUC 更高（分别为 0.97 和 0.99），而中立位下的第一次 CT 扫描 AUC 较低（0.62）。压力试验的理想截断点为旋转测量中的 1.0mm，屈膝位下第二次 CT 扫描的敏感性和特异性分别为 83%和 97%，伸膝位下第三次 CT 扫描的敏感性和特异性分别为 86%和 100%。中立位下第一次 CT 扫描的理想截断点为旋转测量中的 0.7mm，敏感性为 25%，特异性为 97%。
外旋和背屈位下常规踝关节 CT 扫描具有良好的诊断踝关节联合旋转不稳定的性能，与中立位下的踝关节 CT 扫描相比，其 AUC 更大，在理想截断点处的敏感性更高。
