三种方式固定治疗猪Meyers-McKeeverⅢ型前交叉韧带胫骨止点撕脱骨折的生物力学比较研究

Biomechanical comparison study on three fixation methods for the treatment of avulsion fracture of Meyers-McKeever typeⅢanterior cruciate ligament tibial avulsion fracture in swine

目的探讨三种方式固定治疗猪Meyers-McKeeverⅢ型前交叉韧带胫骨止点撕脱骨折的生物力学特性。方法选取猪龄11~16个月新鲜冷冻猪膝关节标本24具,每具膝关节标本仅保留股骨-前交叉韧带-胫骨复合体,骨刀截骨制作Meyers-McKeeverⅢ型骨折模型。24具骨折模型按数字表法随机分为可吸收缝线组、高强线组、全缝线锚钉组3组,每组8具,均行模拟复位固定手术,其中可吸收缝线组采用双股可吸收缝线固定,高强线组采用双股高强非吸收性线固定,全缝线锚钉组采用全缝线锚钉固定。术后24具模型标本均固定于电子万能试验机进行生物力学测试。观察项目:(1)观察Meyers-MckeeverⅢ型骨折模型制备情况及3组骨折模型模拟手术复位、固定情况。(2)对比3组模型的初始位移、屈服载荷、峰值载荷、失效载荷、固定强度等生物力学测试指标。(3)生物力学试验完成后,统计各组模型的内固定失效模式。结果(1)24具骨折模型标本均制备成功,前交叉韧带胫骨止点撕脱骨块完整,骨道周围骨结构无爆裂。3组骨折模型经模拟手术骨折均解剖复位,固定材料置入准确在位,牢固固定。(2)可吸收缝线组的初始位移、屈服载荷、峰值载荷、失效载荷、固定强度分别为(3.64±0.34)mm、(358.19±26.03)N、(397.62±49.78)N、(92.36±5.40)N、(41.10±4.65)N/mm,高强线组分别为(3.63±0.51)mm、(358.83±38.04)N、(416.24±50.87)N、(93.85±8.48)N、(41.70±4.28)N/mm,全缝线锚钉组分别为(2.93±0.73)mm、(401.30±30.59)N、(427.50±40.95)N、(107.06±13.34)N、(47.46±5.97)N/mm。全缝线锚钉组的初始位移小于可吸收缝线组和高强线组,屈服载荷、失效载荷、固定强度均大于可吸收缝线组和高强线组,差异均有统计学意义(P值均<0.05);而可吸收缝线组与高强线组初始位移、屈服载荷、失效载荷、固定强度比较,差异均无统计学意义(P值均>0.05)。3组间的峰值载荷比较,差异无统计学意义(P>0.05)。(3)3组模型内固定失效模式有前交叉韧带切割损伤、缝线滑脱、撕脱骨块再骨折3种,其中可吸收缝线组前交叉韧带部分切割损伤1例、撕脱骨块再骨折7例,高强线组缝线滑脱1例、前交叉韧带部分切割损伤1例、撕脱骨块再骨折6例,全缝线锚钉组8例均为撕脱骨块再骨折。结论可吸收缝线固定与高强线固定前交叉韧带胫骨止点撕脱性骨折的生物力学特性相当;全缝线锚钉作为一种新型固定材料,采用其固定的早期生物力学特性明显优于可吸收缝线及高强线固定。

Objective This study aimed to explore the biomechanical characteristics of three fixation methods for the treatment of Meyers-Mckeever typeⅢanterior cruciate ligament tibial avulsion fracture in swine.Methods A total of 24 fresh and frozen knee joint specimens of pigs aged 11-16 months were selected.The femur-anterior cruciate ligament-tibia complex was retained in each knee joint specimen.A Meyers-McKeever typeⅢfracture model was established using a bone knife.The 24 fracture models were randomly divided into three groups(eight in each group):absorbable suture group,high-strength suture group,and all-suture anchor group.All fracture models simulated reduction and fixation operation,in which the absorbable suture group was fixed with double-strand absorbable suture,the high-strength suture group was fixed with double-strand high-strength non-absorbable suture,and the all-suture anchor group was fixed with all-suture anchor.After operation,24 model specimens were fixed in the electronic universal testing machine for biomechanical testing.(1)The preparation of Meyers-McKeever typeⅢfracture model and the reduction and fixation of the three groups of fracture models were observed.(2)The initial displacement,yield load,peak load,failure load,and fixation strength of the three fracture models after reduction and fixation were compared.(3)After the biomechanical test was completed,the internal fixation failure modes of all fracture models were recorded.Results(1)All 24 fracture model specimens were successfully prepared.The bone block at the tibial interstitial point of anterior cruciate ligaments was intact.The bone structure around the bone canal was intact without bursting.All fracture models in the three groups were anatomically reduced,the fixation materials were placed accurately and firmly fixed.(2)The initial displacement,yield load,peak load,failure load,and fixed strength of the absorbable suture group were(3.64±0.34)mm,(358.19±26.03)N,(397.62±49.78)N,(92.36±5.40)N,and(41.10±4.65)N/mm,respectively;those of the high-strength suture group were(3.63±0.51)mm,(358.83±38.04)N,(416.24±50.87)N,(93.85±8.48)N,and(41.70±4.28)N/mm,respectively;and those of the all-suture anchor group were(2.93±0.73)mm,(401.30±30.59)N,(427.50±40.95)N,(107.06±13.34)N,and(47.46±5.97)N/mm,respectively.The initial displacement of the all-suture anchor group was lower than that of the absorbable suture group and the high-strength suture group,whereas the yield load,failure load,and fixed strength were higher than those of the absorbable suture group and the high-strength suture group,with statistical significance(all P values<0.05).No significant difference was found in the initial displacement,yield load,failure load,and fixed strength between the absorbable suture group and the high-strength suture group(all P values>0.05).No significant difference was observed in the peak load among the three groups(P>0.05).(3)The failure modes of the internal fixation model in 3 groups included anterior cruciate ligament cutting injury,suture slip,and avulsion bone mass refracture.The absorbable suture group had one case of anterior cruciate ligament partial incision injury and seven cases of avulsion bone mass fracture.The high-strength suture group had one case of suture slip,one case of anterior cruciate ligament partial incision injury,and six cases of avulsion bone mass refracture.The all-suture anchor group had eight cases of avulsion bone mass refracture.Conclusion The biomechanical properties of fixation with absorbable suture are similar to those of fixation with high-strength suture for tibia avulsion fracture of the anterior cruciate ligament.As a new type of fixation material,the early biomechanical properties of the all-suture anchor are evidently better than those of absorbable suture and high-strength suture fixation.