| Research backgroundAnkle injury is a common trauma, which accounts for about 25% of the body’s musculoskeletal system injuries, including simple fracture, simple ligament injury or ligament injury and fracture. Nowadays orthopedic surgeons have reach a consensus that when the fracture of ankle joint occurs we should adopt the internal fixation or external fixation to make anatomical restoration depending on injury situation. There are still some different points about that how to treat the injuries when the ankle joint injuries involve the injury of ligament. And due to inappropriate treatment, some patients have disabilities disordering life and work. Many patients and surgeons consider partial or overall injuries of simple inferior tibiofibular symphysis to be minor injuries because the pain and swelling or other symptoms would be eased after relaxation, analgesia and other simple treatment. Because of the mentioned factors, some surgeons failed to pay attention to these injuries and failed to give patients full and correct treatment so that these resulted some sequelae including chronic pain, decreasing capacity of exercise, limited mobility and others. It is necessary to further study and research what the partial or overall injuries of simple inferior tibiofibular symphysis will impact the ankle joint. Since there is often no symphysis separation performance on the X-ray photograph, as well as the difficulty of direct repair, many scholars use plaster to fix so that the inferior tibiofibular symphysis could heal naturally. Nevertheless the long-time using of plaster may disorder the ankle joint function, as well as insufficient braking capacity, which could lead the poor healing and need to fix or rebuild inferior tibiofibular symphysis. In the view of the mentioned importance, some scholars suggest that we should fix the symphysis early to promote the healing at a stable state. There are many ways to fix it, such as a single screw fixation, screws fixation,plate fixation,a pair screws fixation, plastic fixation or others. The single screw fixation is commonly used in clinical practice. This method has some certain defects, such as fixed strength,but can not completely recover analogue syndesmosis fretting characteristics; breakage or other complications. But it is simple and operated easily and can provide an effective stable role for it. Yet, after the fixation we should further study what impact it will make.Ankle injuries often involve the medial structures-malleolus, the triangular ligament, the outer structure-lateral malleolus,lateral triangular ligament and middle tibiofibular syndesmosis. For this type of injury,generally,it is treated by internal fixation.But in view of the difficulties of repair of medial deltoid ligament, many scholars often only use the method of repairing the outer structure and fix tibiofibular syndesmosis; Also, some scholars adopt Boden Theory to repair the internal and outer structures, not to fix tibiofibular syndesmosis, in order to reduce the effect of fixation of tibiofibular syndesmosis; These methods have a certain effect on the clinical, but some patients need further surgery to repair the medial deltoid ligament or fix (rebuild) tibiofibular syndesmosis. For this reason, some scholars repair all the three columns; There is no comprehensive case studies of comparison of the efficacy of three methods and the impact on the ankle, to be further explored.It is very difficult to solve these two problem above by clinical comparative study, because it requires a lot of cases and followed up for a long time. With the development of biomechanics and application of pressure sensitive film,many scholars adopt the method to detect joint force area, the stress positions and size of the force,to describe the impact on the joints of a certain state,the desired results,sovle problems and guide the clinical work. This method is relatively simple, short time required and answer questions from a biomechanical point of view and it’s worth learning.In this study,which is from the viewof biomechanics,use fresh frozen specimens to simulate surgery models of tibiofibular syndesmosis injury, syndesmosis fixation and three columns of ankle injury.Use previous studies to detect biomechanics of ankle,test the effect of ankle biomechanics of various states and analyze the date comparatively,to demonstrate the importance of the fixation to tibiofibular syndesmosis injury and compare the pros and cons among surgery methods of ligament’s three columns injury. Provide a theoretical basis for clinical treating of surgery methods of tibiofibular syndesmosis injury and multi ankle ligament injury,to improve the clinical efficacy of such injury, and reduce disability.Objective1. Using the ankle specimens of fresh frozen corpse, we make the models which are divided into normal group, syndesmosis partial injury group (anterior lower tibiofibular ligament), and all inferior tibiofibular ligament injury group.Then, to explore the dangers of syndesmosis injury and emphasize the importance of intactness of the tibiofibular syndesmosis,we test and compare the biomechanical properties.2. By comparing the ankle’s biomechanical properties between normal ankle and tibiofibular syndesmosis totally Injury treated by Single-screw fixation,we explore whether it can provide similar biomechanical environment of normal ankle to promote healing ligament,while tibiofibular syndesmosis treated by single screw fixation provide the stabilization of the joint.3. To simulate surgeries in the three columns injury of ankle specimens in fresh frozen corpse involved medial the triangular ligament and tibiofibular syndesmosis injury,we explore which surgery method is better for ankle rehabilitation to reduce such injuries morbidity,by comparing the effects of various operation methods on the ankle biomechanics.Method1.Using six adult fresh ankles(Jinan University), they are 4 men and 2 women,70-80 years old (about 74 years old),which are each three for left and right ankle. Visual observation and X-rays showed no fracture inside, infections, tumors and anatomical variation in these ankles and the experiment was not found that there is injury in the medial and lateral ligaments of ankle joint.The specimens are soaked by saline, wrapped by park gauze, loaded and sealed in double plastic bags after numbered and stored at -20℃.2.Specimen preparation:take these specimens out 24 hours before experiment and thaw them naturally by liquid at room temperature (20-25℃). Mutilate them 25cm away from the ankle and keep the leg and foot, ankle.3.Specimen grouping and preparation:Group A(normal group):The medial and lateral ligaments of ankle joint and tibiofibular syndesmosis of the specimens are intact.Group B:mutilate the anterior ligament of tibiofibular syndesmosis from group A as the group of tibiofibular syndesmosis partial injury.Group C:mutilate totally tibiofibular syndesmosis from group B;the first part act as the group of tibiofibular syndesmosis completely rupture.;In the second part,perform the simulation surgery that totally reconstruct the shape and tension after medial and lateral ligaments injury,as the surgery group of tibiofibular syndesmosis with no fixation.Group D:put a 3.5mm cortical bone screws in the group C’s specimen;In the first part,fix the tibiofibular syndesmosis;In the second part, perform the simulation surgery that totally reconstruct the shape and tension after medial and lateral ligaments injury, as the surgery group of tibiofibular syndesmosis with fixation.Group E:mutilate the medial the triangular ligament from group D. Perform the simulation surgery that totally reconstruct the shape and tension after lateral ligaments injury,and fix the tibiofibular syndesmosis,as the surgery group of medial ligament injury without repairation.4. Group A, B, C, D,E were tested in order. Each specimen in turn was tested under five states following: ①dorsiflexion 10°;②entropion 20°;③ valgus 10°; ④plantar flexion 20°;⑤ neutral position.5.Use BOSE material testing machine to load. Fix the leg side of the specimens by clamp in the test machine and plantar side on the rotating horizontal plate,to simulate adults stand phase.Be careful not to damage tendons and ligaments anterior to the joint capsule and protect the upper and lower articular surface of the tibiotalar joint during this process. Implant the electronic pressure sensor (K-Scan 4000, TeKscan, Inc, USA) in the ankle joint cavity; All specimens at a rate of 50N/S of the axial load are applied to 700N, and we will record the experimental datas of contact area, the stress magnitude, the stress position, etc. Each measurement was loaded, unloaded three times and interval time is 50 seconds, only to record the third result.This can reduce the impact of ankle viscoelastic, to obtain relatively stable kinematic measurements.In the experiment,remember to spray the specimens with isotonic saline to minimize tissue degeneration caused by experiment.6. Data was collected by analysis software system, in accordance with the requirements of pre-experiment, the experiment of three specimens of each experiment state data extraction, where in the data selecting joint contact area, internal stress of the joint, the data classification and sorting, draw the corresponding experimental graph joint contact area, stress. The recording and analysis of the experimental data the contact area, the stress magnitude, the force location.7. Statistical analysis:Statistical data, including the size of the ankle joint force tibial articular surface of the talus, the average stress on the size of the force area, as well as the forces of the image plane by force. The data were analyzed, including the force area and mean stress two, data were described by mean±standard deviation (X±s) in the form.In the part one, the following experimental state were statistically analyzed:(1) compare the the force area and stress of the ankle ligament intact group (A group) and ligament damage state groups (B/C/D group); (2) compare the the force area and stress of the part of tibiofibular ligament injury group (group B) and complete syndesmosis injury group (group C); (3) compare the the force area and stress of the fixed group (D group) and not fixed groups (B/C group).In the part two, the following experimental state were statistically analyzed: compare the the force area and stress of the ankle ligament intact group (A group) and ligament repaired by different methods groups (C/D/E group); (2) compare the the force area and stress of medial deltoid ligament repaired group (group D) and not repaired group (E group); (3) compare the the force area and stress of the inferior tibiofibular joint damage fixed groups (D group/E group) and not fixed group (group C).SPSS 22.0 was used for the statistical analysis. The homogeneity test of variance was performed to dermine the analysis method was Fisher’s ANOVA or Welch-Aspin test. If the differences were statistically significant according to ANOVA, the data then were compared among the groups, of which the homogenous ones were analyzed by LSD test,and the heterogenous ones were anlayzed by Dunnett’s test.P<0.05 was set as the significance level, and P<0.05 was set as the great significance level.Results1. The force area results of each group in various states follows:(Table 1)The average of force area in A group is the largest, followed by D group, larger than B group or C group. In all position, The data of group A and B,A and C were a significant difference (P<0.05).In dorsiflexion, entropion,neutral position, valgus position,Group A and Group D data were difference and the difference was statistically (P<0.05).In plantar flexion position,, Group A and Group D data were not difference. In all position, The data of group D and B,D and C were a significant difference (P<0.05).2.The stress magnitude results of each group in various states follows:(Table 2)In all position,the average of stress in group A is the least, following groupD,B and C. In all position, The data of group A and B,A and C were a significant difference (P<0.05).In entropion,neutral position,,Group A and Group D data were difference and the difference were statistically (P<0.05).In dorsiflexion, valgus, plantar flexion, position,, Group A and Group D data were not difference. In all position, The data of group D and B,D and C were a significant difference (P<0.05).3. The force area results of each group in various states follows:(Table 3)The average of force area in A group is the largest, followed by D group, E group and C group. In all position, The data of group A and C,A and E were a significant difference (P<0.05). In dorsiflexion, entropion,neutral position, valgus position,Group A and Group D data were difference and the difference was statistically (P<0.05).In plantar flexion position,, Group A and Group D data were not difference. In all position, The data of group D and C,D and E were a significant difference (P<0.05).4. The stress magnitude results of each group in various states follows:(Table 4)In all position,the average of stress in group A is the least, following groupD,E and C. In all position, The data of group A and C was a significant difference (P <0.05).The Average stress of group E is larger than group A, but only in valgus, entropion the difference was statistically(P<0.05);in other position there was not a significant difference between group A and E..The Average stress of group E is larger than group A, but only in entropion, neutral position,the difference was statistically(P<0.05),in other position there was not a significant difference between group A and D.The Average stress of group E is larger than group D, but only in valgus, dorsiflexion position the difference was statistically (P<0.05),in other position there was not a significant difference between group D and E.Conclusion1. When anterior lower tibiofibular ligament or tibiofibular syndesmosis rupture in various states of the ankle, articular facet of ankle reduced and the articular surface stress tended to increaseing.When tibiofibular syndesmosis was fixed by screws 4 cortices fixed, ankle surface by the force area and stress, although in some states can not fully restore normal biomechanics of the ankle joint, but were significantly better than anterior lower tibiofibular ligament or tibiofibular syndesmosis rupture groups. From the above results, it can be inferred that when the patient’s tibiofibular syndesmosis rupture, it must be fixed. If syndesmosis is not effectively fixed, it may cause postoperative ankle instability, reducing of articular surface and increaseing of the stress. There is more risk of traumatic arthritis. On the contrary, as a solid fixed syndesmosis damaged, we can effectively stabilize the ankle and promote its healing.But how to fix is a question.2.When Ankle ligament damage which leads to the medial and lateral collateral ligaments (bone) fracture, inferior tibiofibular ligament completely broken; medial and lateral collateral ligaments ligaments intact (or repair), and after the effective fixed syndesmosis, ankle joint surface by the force area and stress in some states can not fully return to normal ankle biomechanics, but so much better than in the only lateral collateral ligament intact (or repair) without fixed syndesmosis; or simply make the lateral collateral ligaments intact (or repair), fixed syndesmosis without repair the medial collateral ligament. Therefore, these patients experience clinically, the ankle damage were given to repaire three columns was better than to handle two columns. It could reduce stress concentration, as much as possible so that patients recover motor function, to avoid postoperative ankle stubborn pain and traumatic osteoarthritis occurs. But when the ankle joint injuries while three columns, how to repair the same time, needs further exploration.3. This study have some deficiencies:1. If we have more specimens, the researchers will be more perfect.2. The rotation biomechanics were not researched, and further research needs to be supplemented.3. In our study, the load force only simulate the body’s normal standing position, the bearing strength is far greater than standing force when human walk and run. Due to the deficiencies of the research, the next step is to conduct large case-control studies and advise the clinical treatment.4. How better to repair fixed syndesmosis and how to repair the same time, three-column fixed ankle injury requires further exploration... |
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