目的 比较不同固定方法治疗不稳定骨盆骨折的生物力学稳定性，为临床治疗提供参考。方法 使用三维有限元方法，建立一侧骶髂关节脱位合并耻骨支骨折的不稳定骨盆骨折模型（Tile C型），前方采用改良Stoppa入路（anterior pelvic Stoppa approach, ASA)、前方经皮入路(anterior pelvic approach, APA)、传统的髂腹股沟入路(anterior pelvic ilioinguinal approach, AIA)、外固定架(anterior pelvic external fixation, AEF)4种方法固定，后方采用骶髂螺钉固定（sacroiliac joint screw, SIJS）和经皮重建钢板（posterior tension-band plate,PTP)两种方法固定，并比较分析模拟站立状态时8种不同组合固定方法下骨盆环Von Mises 应力、应变分布情况。结果 加载竖直方向500 N载荷后，在前方内固定组中，骨折处的最大应力均被限制在10 MPa以下。内固定前、后方的最大应力分布ASA＜AIA＜AEF＜APA；在相同应力下，平均位移为ASA＜AIA＜AEF＜APA。而在后方固定组中 PTP组在骶髂关节处及内固定后方的最大应力明显小于SIJS组，且在骶髂关节和骨折处的最大总位移和垂直位移也比SIJS组要小。结论 不稳定性骨盆骨折在8种组合方法植入物的固定后均能得到明显改善，但采用ASA、AIA治疗前环损伤的生物力学总体性能要优于APA和AIA治疗的方法，PTP治疗后方损伤稳定性要优于SIJS固定。

Objective To compare the biomechanical stability of different fixation methods for unstable pelvic fractures, so as to provide references for clinical treatment. Methods An unstable pelvic fracture model (Tile C) with the sacroiliac joint dislocation at one side and the pubic rami fracture was constructed via three-dimensional finite element method. In the front of the pelvis, the fracture models were fixed with anterior pelvic Stoppa approach (ASA),subcutaneous anterior pelvic approach (APA), anterior pelvic ilioinguinal approach (AIA) and anterior pelvic external fixation (AEF),and the rear was fixed with sacroiliac joint screw (SIJS）and posterior tension-band plate (PTP). The Von Mises stress and strain distributions of fracture models fixed by different combinations of fixation approaches were analyzed under simulated standing conditions. Results After the models were applied with 500 N vertical load, the maximum stresses at the fracture sites were all reduced, which were smaller than 10 MPa in the front of the pelvis. The maximum stress at the anterior and posterior part of implants in sequence was ASA＜AIA＜AEF＜APA, and the average displacement under the same stress in sequence was ASA＜AIA＜AEF＜APA. Meanwhile, the maximum stresses at the sacroiliac joint and the posterior part of implants in PTP group were significant smaller than those in SIJS group, and the maximum total displacement and vertical displacement in PTP group were also smaller than those in SIJS group. Conclusions Unstable pelvic fractures could be significantly improved when the fracture was fixed by implants in eight combined methods. However, the overall biomechanical properties of the AIA groups were superior to those of the AEF groups and the APA groups. The stability of PTP groups in the treatment of posterior injury was better than that of SIJS groups.

浙江省医药卫生一般研究计划（2014KYB262），温州市科学技术局项目（Y20130330）