| Objective: Tibial avulsion fracture of the anterior cruciate ligament(ACL)is one of the most common intra-articular fractures,If the patients with obvious displacement were treated with conservative treatment,fracture healing and ACL relaxation could be found.Therefore,many scholars advocate the anatomical reduction and rigid internal fixation of displaced fractures,in order to restore the biomechanical function of ACL.At present,the gold standard for the treatment of tibial avulsion fracture of ACL is arthroscopic reduction and internal fixation,Arthroscopic surgery has replaced the traditional open surgery because of its small trauma,rapid postoperative recovery and less complications,but the fixation remains controversial.There is a lot of literature describing the different methods of arthroscopic fixation of ACL tibial avulsion fracture,the fixation materials are commonly used hollow screw and suture,suture anchors,steel wire tension belt,button plate etc.For the common type ?,?(Meyers-McKeever-Zaricanyj classification)ACL tibial avulsion fractures,arthroscopic reduction of hollow tension screw and suture fixation are two commonly used methods.The study found that the suture fixation can be used for the treatment of type III and IV fractures without considering the shape and size of the fracture.Its advantage is not easy to cause fracture of the fracture block again,no secondary surgery to remove the suture;The disadvantage is that the operation technique is high,the operation time is relatively long,and the fixation time is long,so it is easy to cause complications such as stiffness of knee joint,limitation of motion and muscle atrophy.The suture has a cutting effect on the parenchyma of the ACL,which can cause ACL damage and affect the function of knee joint.Sutures are retained in the articular cavity and tissues for a long time,which may lead to suture reaction,causing joint inflammation and pain.Suture through the epiphyseal plate in children,can cause growth retardation.It has been reported that the absorbable cannulated screw fixation has achieved satisfactory results.Its outstanding advantages are made of bioabsorbable material,no secondary surgery to remove the internal fixation,but the minimum diameter of 4.5mm,not suitable for small fracture of the fixed,but also prone to fracture block fragmentation.In addition,the clinical use of absorbable hollow tension screw in the absorption process often occurs in the nut and screw connection fracture,the nut will be free from the joint cavity,thus forming the free body,easily lead to articular cartilage damage,joint pain and limited mobility And other symptoms.The study found that the clinical hollow tension screw fixation also achieved satisfactory results,but there are still defects,For example:(1),The nut protruding in the joint cavity,easily lead to intercondylar fossa impact,destruction of the femoral condyle cartilage surface,eventually leading to osteoarthritis;(2),The fixed clamping force is insufficient,the thread and the bone channel are easy to float,so that the screw loosening,internal fixation failure,fracture nonunion;(3),Screw in force is too large,easily lead to fracture block fragmentation.Double-headed compression screw is used in the clinical treatment of traumatic fracture fixation,fixation is reliable,its nut with screw thread,Can be screwed into the bone,to avoid the impact of adjacent joints,It is a double threaded structure,when fixed ACL tibial avulsion fracture,fixation strength may be stronger than the hollow tension screw and suture,And the literature review,no report of double hollow compression screw for fixation of tibial avulsion fracture of ACL,Therefore,we assume that the DHSN fixed ACL ltbia avulsion fracture of the biomechanical strength is not worse than the hollow screw and suture fixation,and the double-headed compression screw nut buried fracture block,can avoid the occurrence of complications of intercondylar fossa.So,this study aims to compare the biomechanical comparisons of ACL tibial avulsion fractures with double-headed compression screw,hollow tension screw and suture to evaluate the biomechanical properties of double-headed compression screw fixation ACL tibial avulsion fracture,To provide a theoretical basis for the clinical use of double-headed compression screw fixation ACL tibial avulsion fractures.Method: Choose 30 cases of about 1 year old,weighing about 100 Kg adult pig knee.According to the random number table method,30 cases were divided into three groups,corresponding to the double-headed compression screw group(group A),hollow tension screw group(B group)and suture group(group C),Each group haS 10 cases of knee joint.The proximal femur and distal tibia were cut off at 10 cm above and below the knee and knee joint.All the soft tissue around the knee was resected with a scalpel,leaving only the femur-ACL-tibia complex.The upper end of the femur and the lower end of the tibia are filled with self curing denture powder.A 30mm(long)*15mm(wide)*8.5mm(deep)fracture block was used to simulate the type III fracture of the tibia in three groups of patients with a bone knife(ACL).After anatomical reduction of each group,the three groups were treated with a diameter of 3.5mm double-headed compression screw,a diameter of 3.5mm of the hollow tension screw and two 2 UltraBraid suture fixation.The specimens were stored at-20 ° C and thawed at room temperature 24 hours before the experiment.Through the electronic universal testing machine to measure and record the cyclic load(initial displacement)and the failure load(peak load,yield load),visual observation and record the failure type and A,B group of screws nut embedded in the basic situation of ACL.Data will be analyzed by SPSS17.0 software,the measurement data expressed by the mean and standard deviation,the comparison between the two groups using independent sample t test,the three groups were analyzed by one-way ANOVA,the test level of bilateral,alpha =0.05,P < 0.05 for the difference was statistically significant.Result:In this study,30 cases of porcine knee joint specimens were successfully constructed,the fracture block was complete,and the length,width and depth of fracture were not statistically significant.30 cases of specimen fractures were anatomical reduction,and three kinds of internal fixation materials fixed bone position are good.The peak loads of group A,B and C were(443.10 ± 8.54)N,(361.70 ± 18.76)N and(457.00 ± 26.53)N,respectively.The peak load of group A was significantly larger than that of group B(p <0.05),the difference was statistically significant.The peak load of group A was similar to that of group C,the difference was not statistically significant(p> 0.05).The yield loads of the three groups were(398.10 ± 14.21)N,(324.80 ± 17.50)and(457.00 ± 26.53)N,respectively.The yield load of group A was significantly higher than that of group B(p <0.05),the difference was statistically significant.The yield load of group A was significantly smaller than that of group C(p <0.05),the difference was statistically significant.The initial displacement of the three groups was(1.38 ± 0.14)mm,(1.94 ± 0.12)mm and(3.98 ± 0.19)mm,respectively.The initial displacement of group A was significantly shorter than that of group B and C(p <0.05),the difference was statistically significant.And the initial displacement of the cyclic load of all 10 samples in group A was shorter than the initial displacement of group B and group C.All the specimens in group A were embedded in the ACL substance,and all the specimens in group B were significantly prominent in ACL.Conclusion: The initial stability and mechanical strength of the tibial avulsion fracture are significantly higher than those of the hollow tension screw.The mechanical strength of the tibial avulsion fractures is similar to that of the suture fixation,but the initial stability is significantly higher than that of the suture.Double-headed pressure screw nut can be embedded in the ACL substance,will not cause intercondylar fossa impact and other complications.So double-headed compression screw fixation is suitable for type? and ?. |
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