Everhart Joshua S, Sojka John H, Kaeding Christopher C, Bertone Alicia L, Flanigan David C
College of Medicine, The Ohio State University, United States; Orthopaedics, The Ohio State University Wexner Medical Center, United States.
College of Medicine, The Ohio State University, United States.
Knee. 2017 Jun;24(3):601-607. doi: 10.1016/j.knee.2017.01.013. Epub 2017 Mar 21.
Anterior cruciate ligament (ACL) injuries do not effectively heal. Tendon graft tissue after reconstruction shows rapid tissue turnover and 'ligamentization.' It is unknown whether native torn ACL tissue undergoes significant collagen turnover after injury or is arrested by the intraarticular environment. It is also unknown whether injury mechanism or chronicity affect torn ligament tissue turnover.
Thirty-three mid-substance ACL biopsies were obtained during primary arthroscopic ACL reconstruction (n=31; nine contact injuries, 22 non-contact injuries, 22 males, 11 females; mean age 28.5 years; median injury to surgery time 12 weeks), or from cadavers as uninjured ACL (n=2). As a marker for collagen turnover, immature collagen cross-link content was determined by ninhydrin reagent assays. The immature cross-link content was assessed against injury mechanism, patient age, and injury to surgery time. Histochemical analysis was conducted on two uninjured ACL cadaveric controls, a four-week-old ACL tear, and a four-year-old ACL tear.
Contact and non-contact groups were not demographically different with respect to sex, patient age, injury to surgery time, and activity involvement prior to injury, which ranged from basketball to logging. Collagen crosslink content was very low across all samples, suggesting high tissue turnover between injury and surgery regardless of injury mechanism (non-contact: 1.68ng/mol, CI 0.48-2.89; contact: 1.50ng/mol, CI 0.14-2.86; p=0.842).
Collagen turnover occurs rapidly after ACL injury regardless of contact or non-contact mechanism. Robust tissue turnover starts within the first several weeks after injury and persists to some extent throughout the life of the torn ACL.
前交叉韧带（ACL）损伤无法有效自愈。重建后的肌腱移植组织显示出快速的组织更新和“韧带化”。目前尚不清楚天然撕裂的ACL组织在损伤后是否会经历显著的胶原周转，或者是否会被关节内环境所抑制。同样未知的是损伤机制或损伤时间是否会影响撕裂韧带组织的周转。
在初次关节镜下ACL重建过程中获取了33份ACL中间部分活检样本（n = 31；9例接触性损伤，22例非接触性损伤，22例男性，11例女性；平均年龄28.5岁；损伤至手术的中位时间为12周），或从尸体获取未受伤的ACL样本（n = 2）。作为胶原周转的标志物，通过茚三酮试剂测定法确定未成熟胶原交联含量。根据损伤机制、患者年龄和损伤至手术时间评估未成熟交联含量。对两个未受伤的ACL尸体对照、一个四周龄的ACL撕裂样本和一个四岁龄的ACL撕裂样本进行了组织化学分析。
接触性损伤组和非接触性损伤组在性别、患者年龄、损伤至手术时间以及损伤前的活动参与情况（从篮球运动到伐木工作）方面在人口统计学上无差异。所有样本中的胶原交联含量都非常低，这表明无论损伤机制如何（非接触性损伤：1.68ng/mol，CI 0.48 - 2.89；接触性损伤：1.50ng/mol，CI 0.14 - 2.86；p = 0.842），损伤与手术之间的组织更新都很高。
无论接触性或非接触性机制，ACL损伤后胶原周转都迅速发生。强大的组织更新在损伤后的最初几周内开始，并在撕裂的ACL的整个生命周期中在一定程度上持续存在。
