MOTION Science Institute, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC.
Department of Statistics, University of California at Santa Cruz, Santa Cruz, CA.
Med Sci Sports Exerc. 2022 Oct 1;54(10):1771-1781. doi: 10.1249/MSS.0000000000002969. Epub 2022 Jun 11.
Greater articular cartilage T1ρ magnetic resonance imaging relaxation times indicate less proteoglycan density and are linked to posttraumatic osteoarthritis development after anterior cruciate ligament reconstruction (ACLR). Although changes in T1ρ relaxation times are associated with gait biomechanics, it is unclear if excessive or insufficient knee joint loading is linked to greater T1ρ relaxation times 12 months post-ACLR. The purpose of this study was to compare external knee adduction (KAM) and flexion (KFM) moments in individuals after ACLR with high versus low tibiofemoral T1ρ relaxation profiles and uninjured controls.
Gait biomechanics were collected in 26 uninjured controls (50% females; age, 22 ± 4 yr; body mass index, 23.9 ± 2.8 kg·m -2 ) and 26 individuals after ACLR (50% females; age, 22 ± 4 yr; body mass index, 24.2 ± 3.5 kg·m -2 ) at 6 and 12 months post-ACLR. ACLR-T1ρ High ( n = 9) and ACLR-T1ρ Low ( n = 17) groups were created based on 12-month post-ACLR T1ρ relaxation times using a k-means cluster analysis. Functional analyses of variance were used to compare KAM and KFM.
ACLR-T1ρ High exhibited lesser KAM than ACLR-T1ρ Low and uninjured controls 6 months post-ACLR. ACLR-T1ρ Low exhibited greater KAM than uninjured controls 6 and 12 months post-ACLR. KAM increased in ACLR-T1ρ High and decreased in ACLR-T1ρ Low between 6 and 12 months, both groups becoming more similar to uninjured controls. There were scant differences in KFM between ACLR-T1ρ High and ACLR-T1ρ Low 6 or 12 months post-ACLR, but both groups demonstrated lesser KFM compared with uninjured controls.
Associations between worse T1ρ profiles and increases in KAM may be driven by the normalization of KAM in individuals who initially exhibit insufficient KAM 6 months post-ACLR.
更大的关节软骨 T1ρ 磁共振成像弛豫时间表明蛋白聚糖密度较低，与前交叉韧带重建（ACLR）后创伤后骨关节炎的发展有关。虽然 T1ρ 弛豫时间的变化与步态生物力学有关，但尚不清楚 ACLR 后 12 个月时，膝关节过度或不足的负荷是否与更大的 T1ρ 弛豫时间有关。本研究的目的是比较 ACLR 后 T1ρ 弛豫时间高与低的患者与未受伤对照组之间的膝关节外展（KAM）和屈曲（KFM）力矩。
在 26 名未受伤的对照组（50%为女性；年龄，22 ± 4 岁；体重指数，23.9 ± 2.8 kg·m -2 ）和 26 名 ACLR 后患者（50%为女性；年龄，22 ± 4 岁；体重指数，24.2 ± 3.5 kg·m -2 ）中，在 ACLR 后 6 和 12 个月采集步态生物力学数据。根据 12 个月后 ACLR 的 T1ρ 弛豫时间，使用 k-均值聚类分析创建 ACLR-T1ρ High（n=9）和 ACLR-T1ρ Low（n=17）组。采用功能方差分析比较 KAM 和 KFM。
ACLRT1ρ High 在 ACLR 后 6 个月时的 KAM 明显小于 ACLR-T1ρ Low 和未受伤对照组。ACLR-T1ρ Low 在 ACLR 后 6 和 12 个月时的 KAM 明显大于未受伤对照组。ACLR-T1ρ High 的 KAM 在 6 至 12 个月之间增加，ACLR-T1ρ Low 的 KAM 在 6 至 12 个月之间减少，两组均变得与未受伤对照组更相似。ACLR-T1ρ High 和 ACLR-T1ρ Low 在 ACLR 后 6 或 12 个月时的 KFM 之间几乎没有差异，但两组的 KFM 均明显小于未受伤对照组。
较差的 T1ρ 图谱与 KAM 增加之间的关联可能是由于 ACLR 后 6 个月时最初表现出 KAM 不足的患者的 KAM 趋于正常所致。
