Heimann Alexander F, Walther Jonas, Tannast Moritz, Schwab Joseph M, Wagner Moritz, Brunner Alexander, Lerch Till D, Steppacher Simon D, Vavron Peter, Schmaranzer Ehrenfried, Schmaranzer Florian
Department of Orthopaedic Surgery, HFR - Cantonal Hospital, University of Fribourg, Chemin des pensionnats 2 - 6, CH-1700, Fribourg, Switzerland.
Department of Orthopaedic Surgery, Inselspital Bern, University Hospital, University of Bern, Freiburgstrasse 18, Bern, CH-3010, Switzerland.
Insights Imaging. 2023 Oct 15;14(1):172. doi: 10.1186/s13244-023-01524-4.
To assess the feasibility of flexion-abduction-external rotation (FABER) magnetic resonance imaging (MRI) of the hip to visualize changes in the ischiofemoral interval and ability to provoke foveal excursion over the acetabular rim.
IRB-approved retrospective single-center study. Patients underwent non-contrast 1.5-T hip MRI in the neutral and FABER position. Two readers measured the ischiofemoral interval at three levels: proximal/distal intertrochanteric distance and ischiofemoral space. Subgroup analysis was performed for hips with/without high femoral torsion, or quadratus femoris muscle edema (QFME), respectively. A receiver operating curve with calculation of the area under the curve (AUC) for the prediction of QFME was calculated. The presence of foveal excursion in both positions was assessed.
One hundred ten patients (121 hips, mean age 34 ± 11 years, 67 females) were evaluated. FABER-MRI led to narrowing (both p < .001) of the ischiofemoral interval which decreased more at the proximal (mean decrease by 26 ± 7 mm) than at the distal (6 ± 7 mm) intertrochanteric ridge. With high femoral torsion/ QFME, the ischiofemoral interval was significantly narrower at all three measurement locations compared to normal torsion/no QFME (p < .05). Accuracy for predicting QFME was high with an AUC of .89 (95% CI .82-.94) using a threshold of ≤ 7 mm for the proximal intertrochanteric distance. With FABER-MRI foveal excursion was more frequent in hips with QFME (63% vs 25%; p = .021).
Hip MRI in the FABER position is feasible, visualizes narrowing of the ischiofemoral interval, and can provoke foveal excursion.
FABER MRI may be helpful in diagnosing ischiofemoral impingement and detecting concomitant hip instability by overcoming shortcomings of static MR protocols that do not allow visualization of dynamic changes in the ischiofemoral interval and thus may improve surgical decision making.
• FABER MRI enables visualization of narrowing of the ischiofemoral interval proximal to the lesser trochanter. • Proximal intertrochanteric distance of ≤ 7 mm accurately predicts quadratus femoris muscle edema. • Foveal excursion was more frequent in hips with quadratus femoris muscle edema.
评估髋关节屈曲 - 外展 - 外旋（FABER）磁共振成像（MRI）以观察坐骨股骨间隙变化及诱发髋臼缘中央凹移位的可行性。
经机构审查委员会批准的回顾性单中心研究。患者在中立位和FABER位接受非增强1.5-T髋关节MRI检查。两名阅片者在三个层面测量坐骨股骨间隙：转子间近端/远端距离和坐骨股骨间隙。分别对伴有/不伴有高位股骨扭转或股方肌水肿（QFME）的髋关节进行亚组分析。计算预测QFME的曲线下面积（AUC）的受试者工作特征曲线。评估两个位置中央凹移位的情况。
共评估110例患者（121个髋关节，平均年龄34±11岁，67例女性）。FABER-MRI导致坐骨股骨间隙变窄（均p <.001），转子间近端变窄更明显（平均减少26±7mm），而远端转子间嵴处减少6±7mm。与正常扭转/无QFME相比，高位股骨扭转/QFME时，在所有三个测量位置坐骨股骨间隙均明显更窄（p <.05）。使用近端转子间距离≤7mm的阈值预测QFME的准确性较高，AUC为0.89（95%CI 0.82 - 0.94）。在伴有QFME的髋关节中，FABER-MRI时中央凹移位更常见（63%对25%；p = 0.021）。
FABER位髋关节MRI可行，可观察到坐骨股骨间隙变窄，并能诱发中央凹移位。
FABER MRI可能有助于诊断坐骨股骨撞击症，并通过克服静态MR协议的缺点来检测伴随的髋关节不稳定，静态MR协议无法观察到坐骨股骨间隙的动态变化，从而可能改善手术决策。
• FABER MRI能够观察到小转子近端坐骨股骨间隙变窄。• 近端转子间距离≤7mm可准确预测股方肌水肿。• 股方肌水肿的髋关节中中央凹移位更常见。
