ABSTRACT

Purpose: Complications including arthrofibrosis have been reported after anterior cruciate ligament reconstruction (ACLR) even under accelerated rehabilitation. To overcome this, we developed an animal model of ACLR-induced arthrofibrosis without immobilization.

Materials and Methods: Thirteen male Wistar rats were divided into ACL transection (ACLT) and ACLR groups. Surgery was performed in the right knees and untreated left knees were used as controls. After surgery, rats could move freely without joint immobilization.

Results: One week after surgery, flexion contracture represented by passive ROM reduction was 49 ± 5° and 21 ± 6° in ACLR and ACLT groups, respectively. Thereafter, flexion contractures were gradually reduced to 21 ± 8° and 12 ± 6° after 12 weeks, respectively. Fibrosis, which is characterized by significant upregulation of fibrosis-related genes, thickening, and adhesion in the posterior joint capsule, was observed in the ACLR group after 12 weeks of surgery. Nociceptive behavior and joint swelling were more apparent in the ACLR group than in the ACLT group, especially after 1 week of surgery.

Discussions: We developed a rat model of ACLR-induced joint contracture due to arthrofibrosis without rigid immobilization. Joint contracture was also observed in the ACLT group, but to a considerably milder degree than in the ACLR group. Thus, signs of inflammation as a result of reconstruction surgery, rather than ACL transection, play an important role in the formation of joint contracture after ACLR. Our animal model is suited to examine the mechanisms and efficacy of therapeutic strategies for arthrofibrosis following ACLR treated without rigid joint immobilization.

摘要

目的：前交叉韧带重建 (ACLR) 后甚至在加速康复的情况下也报告了包括关节纤维化在内的并发症。为了克服这一点，我们开发了一种无需固定的 ACLR 诱导的关节纤维化动物模型。

材料与方法： 13只雄性Wistar大鼠分为ACL横断（ACLT）组和ACLR组。手术在右膝进行，未经治疗的左膝用作对照。手术后，大鼠可以自由活动，无需关节固定。

结果：术后1周，ACLR组和ACLT组以被动ROM减少为代表的屈曲挛缩分别为49±5°和21±6°。此后，屈曲挛缩分别在 12 周后逐渐减少至 21 ± 8° 和 12 ± 6°。ACLR 组在术后 12 周观察到纤维化，其特征是后关节囊纤维化相关基因显着上调、增厚和粘连。ACLR 组的伤害性行为和关节肿胀比 ACLT 组更明显，尤其是在手术 1 周后。

讨论：我们开发了一种由于关节纤维化引起的 ACLR 诱导的关节挛缩大鼠模型，无需刚性固定。ACLT 组也观察到关节挛缩，但程度比 ACLR 组轻得多。因此，重建手术导致的炎症迹象，而不是 ACL 横断，在 ACLR 后关节挛缩的形成中起重要作用。我们的动物模型适用于检查在没有刚性关节固定的情况下进行 ACLR 治疗后关节纤维化治疗策略的机制和疗效。