Figueroa Alonso, Bugajski Tomasz, Humpal Dillon, Kumaravel Manickam, Lowe Walter, Zandiyeh Payam
Department of Orthopedic Surgery, University of Texas, Health Science Center at Houston, Houston, Texas, USA.
Department of Diagnostic and Interventional Radiology, University of Texas, Health Science Center at Houston, Houston, Texas, USA.
Am J Sports Med. 2025 Oct;53(12):2841-2850. doi: 10.1177/03635465251368393. Epub 2025 Sep 19.
The anterior cruciate ligament reconstruction (ACLR) graft undergoes a remodeling process that affects its structural properties. Ultrashort echo time T (UTE-T) imaging has been instrumental in examining this process. However, more research is needed on the postoperative relationship between UTE-T of the graft and its mechanical properties.
To longitudinally examine ACL graft changes after ACLR using UTE-T decay coefficients and knee laxity and explore their relationship.
Case series; Level of evidence, 4.
A total of 31 patients who underwent ACLR had magnetic resonance imaging of their knees at 1, 6, and 12 months after surgery using a UTE-T sequence. Bilateral knee laxity was measured at 6 and 12 months using a GNRB arthrometer (force = 200 N). UTE-T coefficients of the graft were calculated using mono- (T) and biexponential (short [T] and long [T]) analyses, and outcomes were normalized to body mass index. Linear mixed models were used to determine longitudinal changes in UTE-T and laxity; the Pearson correlation was used to explore the correlations between these outcomes.
T of the graft increased from 1 to 6 months (Δ = 0.092; = .008), followed by a decrease from 6 to 12 months (Δ = -0.079; = .021). Regardless of the limb side, a decrease in laxity was detected between 6 and 12 months after surgery (Δ = -0.033; = .046). Positive correlations between laxity and UTE-T were detected at 6 months (T: = 0.285; = .025) and 12 months (T: = 0.532; < .01; T: = 0.669; < .001; T: = 0.354; = .034).
Biexponential analysis of UTE-T MRI provides a sensitive tool for detecting structural changes in the graft after ACL reconstruction, reflecting the dynamic process of graft remodeling. Among the decay coefficients assessed, T demonstrates a stronger correlation with postoperative laxity, highlighting its potential as a critical biomarker for monitoring graft integrity over time.
前交叉韧带重建（ACLR）移植物会经历一个影响其结构特性的重塑过程。超短回波时间T（UTE-T）成像在研究这一过程中发挥了重要作用。然而，关于移植物的UTE-T与其力学性能之间的术后关系，仍需要更多研究。
使用UTE-T衰减系数和膝关节松弛度纵向研究ACLR术后ACL移植物的变化，并探讨它们之间的关系。
病例系列；证据等级，4级。
共有31例行ACLR的患者在术后1个月、6个月和12个月使用UTE-T序列对其膝关节进行磁共振成像检查。在术后6个月和12个月使用GNRB关节测量仪（力=200N）测量双侧膝关节松弛度。移植物的UTE-T系数通过单指数（T）和双指数（短 [T] 和长 [T]）分析计算得出，并将结果按体重指数进行标准化。使用线性混合模型确定UTE-T和松弛度的纵向变化；使用Pearson相关性分析来探讨这些结果之间的相关性。
移植物的T在1至6个月增加（Δ = 0.092；P = 0.008），随后在6至12个月下降（Δ = -0.079；P = 0.021）。无论肢体侧别如何，在术后6至12个月均检测到松弛度降低（Δ = -0.033；P = 0.046）。在6个月（T：r = 0.285；P = 0.025）和12个月（T：r = 0.532；P < 0.01；T：r = 0.669；P < 0.001；T：r = 0.354；P = 0.034）时检测到松弛度与UTE-T之间存在正相关。
UTE-T MRI的双指数分析为检测ACL重建后移植物的结构变化提供了一种敏感工具，反映了移植物重塑的动态过程。在所评估的衰减系数中，T与术后松弛度的相关性更强，突出了其作为随时间监测移植物完整性的关键生物标志物的潜力。
