Li Yongqi, Zhou Haichao, Xia Jiang, Li Bing, Zhao Youguang, He Wenbao, Li Zhendong, Yang Yunfeng
Department of Orthopedics, Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065 China.
Department of Orthopedics, Karamay Central Hospital, Karamay, 834000 China.
Indian J Orthop. 2023 Jul 17;57(9):1461-1472. doi: 10.1007/s43465-023-00951-1. eCollection 2023 Sep.
This study aimed to analyze quantitative correlation between the posterior malleolus fracture and fixation and the rotational stability of the ankle and to explore supplementary surgical indications for posterior malleolus fracture.
Twenty fresh frozen cadaver specimens were selected and dissected. Based on the tibial insertion of the ligament complex, the model for the supination external rotation stage 3 ankle fracture with a posterior malleolar fragment and syndesmosis diastasis was created. The area threshold of the posterior tibial insertion of posterior malleolus fracture was biomechanically assessed and the difference of the antirotating ability stiffness of the ankle between simple posterior malleolus fixation and simple syndesmotic fixation was analyzed statistically.
The tibial insertion of posterior inferior tibiofibular ligament and inferior transverse tibiofibular ligament complex was relatively broad, and its width decreased as the distance from the joint line increased. Biomechanical analysis showed that: the threshold of posterior area of posterior malleolus fracture was 1/4S; posterior malleolus fixation provided better rotational stability than syndesmotic fixation ( 0.01).
The surgical indications for posterior malleolus fracture should consider simultaneously the restoration of the axial and rotational stability of the ankle. Simple posterior malleolus fracture fixation is recommended when the syndesmosis is unstable and the area ratio of posterior tibial insertion of posterior malleolus fracture is greater than or equal to 1/4. Syndesmotic fixation is proposed to restore and maintain the rotational stability of the ankle when the syndesmosis is unstable and the area ratio is less than 1/4. Regardless of the area ratio, the surgical indication only depends on the impact of the posterior malleolus fracture on the axial stability of tibiotalar joint, the involved articular surface area, and the displacement degree of posterior malleolus fragment, when the syndesmosis is stable.
本研究旨在分析后踝骨折与固定和踝关节旋转稳定性之间的定量相关性，并探讨后踝骨折的补充手术指征。
选取20例新鲜冷冻尸体标本并进行解剖。基于韧带复合体的胫骨附着点，建立伴有后踝骨折块和下胫腓联合分离的旋后外旋Ⅲ度踝关节骨折模型。对后踝骨折胫骨附着点的面积阈值进行生物力学评估，并对单纯后踝固定与单纯下胫腓联合固定时踝关节抗旋转能力刚度的差异进行统计学分析。
下胫腓后韧带和下胫腓横韧带复合体的胫骨附着点相对较宽，其宽度随距关节线距离增加而减小。生物力学分析显示：后踝骨折后方区域阈值为1/4S；后踝固定比下胫腓联合固定提供更好的旋转稳定性（P<0.01）。
后踝骨折的手术指征应同时考虑踝关节轴向和旋转稳定性的恢复。当下胫腓联合不稳定且后踝骨折胫骨附着点面积比大于或等于1/4时，建议行单纯后踝骨折固定。当下胫腓联合不稳定且面积比小于1/4时，建议行下胫腓联合固定以恢复和维持踝关节的旋转稳定性。当胫腓联合稳定时，无论面积比如何，手术指征仅取决于后踝骨折对胫距关节轴向稳定性的影响、累及的关节面面积以及后踝骨折块的移位程度。
