Background:Both high body mass index (BMI) and anterior cruciate ligament reconstruction (ACLR) independently influence knee osteoarthritis risk. Preliminary evidence shows the combination of these risk factors leads to poorer recovery and altered biomechanical outcomes after ACLR, but few studies have directly evaluated early changes in cartilage health between normal-BMI and high-BMI groups in this population.Purpose:To evaluate ultrasound-based measures of cartilage strain and compositional changes (via echo-intensity [EI]) in response to an incline walking stress test between normal-BMI and high-BMI individuals with ACLR. A secondary evaluation was conducted of associations between habitual walking biomechanics (ie, ground-reaction forces, sagittal knee kinetics and kinematics) and cartilage strain and EI outcomes.Study Design:Controlled laboratory study.Methods:Gait biomechanics and femoral trochlear ultrasound analyses were evaluated in 64 participants with ACLR who had normal BMI (BMI < 27.0; n = 40) and high BMI (BMI ≥ 27.0; n = 24). Ultrasound images were collected bilaterally before and after an incline treadmill walk, and medial and lateral trochlear strain and EI changes pre-post exercise were used to compare BMI groups and limbs. Gait outcomes included ground-reaction forces, peak sagittal plane knee moments, angles, and excursions and were used to determine associations with cartilage outcomes in the entire cohort.Results:High-BMI individuals with ACLR exhibited greater medial trochlear cartilage strain in the ACLR limb compared with normal-BMI individuals (approximately 6%; P < .01). In those with high BMI, the ACLR limb exhibited greater medial trochlear strain relative to non-ACLR limbs (approximately 4%; P < .05), but between-limb differences were not observed in the normal-BMI group ( P > .05). Medial trochlear EI changes were greater bilaterally in those with high BMI compared with normal-BMI ACLR counterparts (approximately 10%; P < .01). Last, individuals who walked with greater peak knee flexion angles exhibited less medial cartilage strain (Δ R2 = 0.06; P = .025).Conclusion:The data suggested that high BMI affects cartilage functional properties after ACLR, whereas smaller knee flexion angles were associated with larger medial cartilage strain.Clinical Relevance:High-BMI individuals with ACLR may represent a subset of patients exhibiting earlier declines in cartilage functional integrity in response to loading, necessitating additional or more targeted interventions to mitigate disease development.

中文翻译：

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前交叉韧带重建患者运动后体重指数、步态生物力学和体内软骨功能之间的关联


背景： 高体重指数 （BMI） 和前交叉韧带重建 （ACLR） 均独立影响膝骨关节炎风险。初步证据表明，这些风险因素的结合导致 ACLR 后恢复较差和生物力学结果改变，但很少有研究直接评估该人群中正常 BMI 和高 BMI 组之间软骨健康的早期变化。目的： 评估基于超声的软骨应变和成分变化测量 （通过回声强度 [EI]）对正常 BMI 和高 BMI ACLR 个体之间倾斜行走压力测试的响应。对习惯性行走生物力学 （即地面反作用力、矢状膝动力学和运动学） 与软骨应变和 EI 结果之间的关联进行了二次评估。研究设计： 对照实验室研究。方法： 在 64 例 BMI 正常 （BMI < 27.0;n = 40） 和高 BMI （BMI ≥ 27.0;n = 24） 的 ACLR 参与者中评估步态生物力学和股骨滑车超声分析。在倾斜跑步机行走前后收集双侧超声图像，并使用内侧和外侧滑车应变以及运动前后的 EI 变化来比较 BMI 组和肢体。步态结果包括地面反作用力、峰值矢状面膝关节时刻、角度和偏移，用于确定与整个队列中软骨结果的关联。结果： 与正常 BMI 个体相比，ACLR 的高 BMI 个体在 ACLR 肢体中表现出更大的内侧滑车软骨应变 （约 6%;P < .01）.在高 BMI 的患者中，ACLR 肢体相对于非 ACLR 肢体表现出更大的内侧滑车应变 （约 4%;P < .05），但在正常 BMI 组中未观察到肢体间差异 （ P > .05）。与正常 BMI ACLR 患者相比，高 BMI 患者的双侧滑车内侧滑车 EI 变化更大（约 10%;P < .01）.最后，以较大的峰值膝关节屈曲角度行走的个体表现出较少的内侧软骨劳损 （Δ R2 = 0.06;P = .025）。结论： 数据表明，高 BMI 影响 ACLR 后软骨功能特性，而较小的膝关节屈曲角度与较大的内侧软骨拉伤相关。临床相关性： ACLR 的高 BMI 个体可能代表一部分患者，这些患者在负荷反应中表现出软骨功能完整性的早期下降，需要额外或更有针对性的干预措施来减轻疾病的发展。