Hospital for Special Surgery, New York, New York, USA.
The Affiliate Hospital to Nantong University, Nantong, Jiangsu, China.
J Orthop Res. 2023 Jan;41(1):32-43. doi: 10.1002/jor.25346. Epub 2022 May 2.
The relative contributions of sex differences in anatomy, biomechanics, and hormones to the increased risk of anterior cruciate ligament (ACL) injury in female athletes remains unknown. The purpose of this study is to investigate sex differences in anatomy and biomechanics of the native and reconstructed ACL using our established murine model. A total of 140 12-week-old wild-type C57Bl/6 (70 male vs. 70 female) mice were used for this study. ACL reconstruction was performed on 120 mice who were split into four groups: Group 1 (30 males sacrificed at 14 days), Group 2 (30 females sacrificed at 14 days), Group 3 (30 males sacrificed at 28 days), and Group 4 (30 females sacrificed at 28 days). Tendon graft-to-bone healing was assessed by biomechanical, histological, and micro-CT analysis. Twenty mice were used for baseline testing. Females showed significantly higher anterior (p < 0.05) and total displacement (p < 0.05). Males demonstrated a significantly higher load-to-failure force of native ACLs compared to females (p < 0.05). There was no significant difference in load-to-failure force in the ACL autograft. There were no significant sex differences in histological analysis of graft integration or tibial slope. The increased knee laxity and reduced load-to-failure of the native ACL observed in the female mice are consistent with some of the proposed risk factors driving the increased risk of ACL injury in females. Understanding the relative contributions of factors driving sex differences in material properties of the ACL will provide insight into the sex differences in ACL injury and future prevention strategies.
性别差异在解剖结构、生物力学和激素等方面对女性前交叉韧带（ACL）损伤风险增加的相对贡献仍不清楚。本研究旨在使用我们建立的鼠模型研究 ACL 的解剖结构和生物力学的性别差异。本研究共使用了 140 只 12 周龄的野生型 C57Bl/6 小鼠（70 只雄性与 70 只雌性）。120 只小鼠进行了 ACL 重建，分为四组：第 1 组（30 只雄性，在第 14 天处死）、第 2 组（30 只雌性，在第 14 天处死）、第 3 组（30 只雄性，在第 28 天处死）和第 4 组（30 只雌性，在第 28 天处死）。通过生物力学、组织学和 micro-CT 分析评估肌腱移植物与骨的愈合情况。20 只小鼠用于基线测试。女性的前向（p<0.05）和总位移（p<0.05）明显更高。与女性相比，男性的 ACL 固有体的失效力明显更高（p<0.05）。ACL 自体移植物的失效力没有显著差异。移植物整合或胫骨斜率的组织学分析没有明显的性别差异。在雌性小鼠中观察到的 ACL 固有体松弛度增加和失效力降低与一些导致女性 ACL 损伤风险增加的潜在风险因素一致。了解导致 ACL 材料属性性别差异的因素的相对贡献，将有助于深入了解 ACL 损伤的性别差异和未来的预防策略。
