Zhao Yuqing, Chen Wen, Su Tong, Zhou Guangjin, Jiang Dong, Yuan Huishu
Radiology Department, Peking University Third Hospital, No.49 North Garden Road, Haidian, Beijing, 100191, China.
Department of Sports Medicine, Beijing Key Laboratory of Sports Injuries, Peking University Third Hospital. Institute of Sports Medicine of Peking University, No.49 North Garden Road, Haidian, Beijing, 100191, China.
Arch Orthop Trauma Surg. 2023 Apr;143(4):2037-2045. doi: 10.1007/s00402-022-04500-7. Epub 2022 Jun 21.
Chronic lateral ankle instability (CLAI) could accompany with latent syndesmotic diastasis (LSD), which is difficult to distinguish before surgery. Tibiofibular interval width and extravasation of joint fluid ('lambda sign') on MRI are widely used in the diagnosis of syndesmotic injury, but the reliability of these methods in distinguishing the associated LSD in CLAI was rarely studied. Our objective was to compare the diagnostic value of the measurement of the transverse tibiofibular interval and 'lambda sign' on MRI in distinguishing LSD in CLAI and to investigate the radiological predictor that best matched the intraoperatively measured syndesmotic width.
138 CLAI patients undergoing arthroscopy in our institute from March 2017 to June 2020 were enrolled (CLAI group). Anterior space width (ASW) and posterior space width (PSW) at 10 mm layer above tibial articular and fluid height above tibial articular surface (FH) were measured on preoperative MRI. The same parameters were measured on MRI of 50 healthy volunteers as control group. At arthroscopy, syndesmotic width was measured and the patients were divided into arthroscopic widening (AW) and arthroscopic normal (AN) subgroup taking 2 mm as critical value. The CLAI group was compared with the control group to explore the interval changes related to CLAI. The AW and AN subgroups were compared to explore the potential diagnostic indicators and reference values for the LSD.
All parameters showed significant difference between CLAI group and control group (p < 0.05), but only PSW (p = 0.004) showed significant difference between AW and AN subgroups other than FH (p = 0.461). Only PSW was involved in formula of multiple-factor analysis (p = 0.005; OR, 1.819; 95%CI, 1.196-2.767). ROC analysis showed critical value of PSW was 3.8 mm (sensitivity, 66%; specificity, 66%; accuracy, 66.7%), while accuracy of lambda sign was 41.3%.
Transverse tibiofibular interval measurements were more reliable than the 'lambda sign' in distinguishing associated LSD in CLAI patients. The PSW ≥ 3.8 mm could be a predictor of syndesmotic diastasis.
慢性外侧踝关节不稳（CLAI）可能伴有潜在的下胫腓联合分离（LSD），术前难以鉴别。MRI上胫腓间隙宽度和关节液外渗（“λ征”）被广泛用于诊断下胫腓联合损伤，但这些方法在鉴别CLAI相关LSD中的可靠性鲜有研究。我们的目的是比较MRI上测量胫腓横间隙和“λ征”对鉴别CLAI中LSD的诊断价值，并探究与术中测量的下胫腓联合宽度最匹配的影像学预测指标。
纳入我院2017年3月至2020年6月期间接受关节镜检查的138例CLAI患者（CLAI组）。在术前MRI上测量胫骨关节面上方10mm层面的前间隙宽度（ASW）和后间隙宽度（PSW）以及胫骨关节面上方的液体高度（FH）。测量50名健康志愿者的MRI作为对照组，测量相同参数。在关节镜检查时，测量下胫腓联合宽度，并以2mm为临界值将患者分为关节镜下增宽（AW）和关节镜下正常（AN）亚组。将CLAI组与对照组进行比较，以探讨与CLAI相关的间隙变化。比较AW和AN亚组，以探索LSD的潜在诊断指标和参考值。
CLAI组与对照组之间所有参数均有显著差异（p<0.05），但除FH（p=0.461）外，AW和AN亚组之间仅PSW（p=0.004）有显著差异。多因素分析公式中仅涉及PSW（p=0.005；OR，1.819；95%CI，1.196-2.767）。ROC分析显示PSW的临界值为3.8mm（敏感性，66%；特异性，66%；准确性，66.7%），而“λ征”的准确性为41.3%。
在鉴别CLAI患者相关LSD方面，胫腓横间隙测量比“λ征”更可靠。PSW≥3.8mm可能是下胫腓联合分离的一个预测指标。
