Study On The Mechanism Of The Effectiveness Of Lower Limb Longitudinal Bone Traction For High Acetabular Both-Column Fractures Based On The Combination Of Tendons And Bones

Background The basic theory of treating fracture with the combination of traditional Chinese medicine and traditional Chinese and Western medicine is to lay equal stress on both bones and tendons.Bone traction,as an important treatment method reflecting this theory,has been proved to be a safe and effective treatment for long bone fracture.Although the curative effect of bone traction on intra-articular fracture is not as good as that of long bone fracture,bone traction is commonly used in clinical treatment of intra-articular fracture.Acetabular both-column fracture is the most serious intra-articular fracture.Bone traction is effective in traction reduction,but there are many unnecessary traction.Because the mechanism of bone traction on acetabular both-column fracture is still unclear,how to achieve the goal of "laying equal stress on both bones and tendons" remains to be further studied.If its mechanism can be elucidated,it will help to improve the effect of closed reduction of acetabular fracture before and during operation,avoid blind traction,reduce soft tissue in jury,truly realize the concept of "laying equal stress on both bones and tendons "in the treatment of intra-articular fracture,and improve the curative effect of integrated traditional Chinese and Western medicine in the treatment of intra-articular fracture.Objective Based on the theory of both tendons and bones,the mechanism of the effectiveness of longitudinal bone traction in lower limbs of acetabular both-column fractures was discussed in the following three aspects to improve the curative effect of the treatment of intra-articular fractures with integrated traditional Chinese and Western medicine.1.Through clinical retrospective study of traction reduction combined with DAPSQ internal fixation in the treatment of acetabular both-column fractures,to explore the possible causes of failure of bone traction reduction and the relationship between bone traction and surgery.2.The femoral head and acetabulum are connected by the round ligament of the femoral head and the joint capsule,i.e.the tendons and bones.To elucidate the mechanism of bone traction,it is necessary to understand the anatomical structure of the round ligament of the femoral head,which is not well known at present.By studying the course,morphology,attachment anatomy and histological characteristics of the femoral head circular ligament,the structure and mechanical potential of the femoral head circular ligament in bone traction were discussed,which laid a foundation for further mechanism research.3.Based on the establishment of a complete finite element model of hip joint bone and ligament,the mechanism of the effectiveness of lower limb longitudinal bone traction for high acetabular both-column fractures was discussed by analyzing the traction reduction effect of three groups of different ligaments in the presence of high acetabular both-column fractures.Methods Part 1:A retrospective analysis was made of 30 patients with acetabular both-column fractures who underwent open reduction from June 2009 to September 2016.There were 18 males and 12 females with an average age of 45.6 years.All patients with acetabular both-column fracture were treated with tibial tubercle traction according to their body weight from 1/7 to 1/5 before operation.The weight of traction was determined by X-ray examination two days before operation.The traction reduction was performed under anesthesia.Combining with the theory of laying equal stress on both bones and tendons",the causes of difficult reduction of acetabular fracture by bone traction before and during operation and the relationship between bone traction and operation were discussed.All 30 cases of acetabular both-column fractures were difficult to be reduced by traction.Open reduction was finally selected.Open reduction via ilioinguinal approach combined with DAPSQ internal fixation was used to treat acetabular both-column fractures.Thirty patients were followed up for 12 to 44 months(average 28 months)?The hip function was evaluated according to Harris score,modified Merle d Aubigne and Postel function score at the last follow-up.The excellent rate of reduction was evaluated according to Matta imaging criteria before,during,after and at the last follow-up.Part ?:The data of 25 elderly patients with femoral neck fracture who underwent joint replacement in our hospital from August 2017 to June 2018 were prospectively collected.The age ranged from 63 to 88 years,with an average age of 78 years.There were 15 males and 10 females.Firstly,the circular ligament of the femoral head was cut off close to the attachment point of the femoral head concave,and then the attachment point,shape and movement characteristics of the circular ligament of the femoral head on the acetabular fossa were observed after removal of the femoral head:Then the circular ligament was slowly excised and removed with an electric knife at the attachment point of the acetabular fossa.The length of the circular ligament was measured by a sterile ruler with accuracy of 0.5mm and histological examination was carried out by HE staining.The complete structure of the round ligament of the femoral head,which plays a role in bone traction.Meanwhile,its potential mechanical properties in bone traction were confirmed by literature review.Part ?:Based on autopsy,observation of clinical specimens and consulting relevant domestic and foreign literatures,the anatomical morphology,the range of ligament attachment points,the basic properties of ligaments(linear stiffness,elasticity coefficient,cross-sectional area,etc.)of the round ligament of femoral head,iliofemoral ligament,ischiofemoral ligament,pubicfemoral ligament and articular capsule were determined,and then the normal half-pelvic model was established,and its validity was verified,and the standard high acetabulum both-column fracture was established.According to the basic properties of different ligaments,finite element ligament models were established in three groups:the femoral head round ligament,iliofemoral ligament,ischiofemoral ligament,pubicfemoral ligament and hip joint capsule(group A),the circular ligament alone(group B),iliofemoral ligament,ischiofemoral ligament,pubicfemoral ligament and hip joint capsule,and the circular ligament did not exist(group C).When simulated supine position,the traction reduction of high acetabular both-column fracture was analyzed by finite element method in the presence of three groups of ligaments under 600 N load along the femoral shaft direction.Evaluation criteria:(1)The coordinate system was established according to the X axis along the femoral neck,the Y axis along the front and rear edges of acetabulum,and the Z axis along the X and Y axis.According to the location of fracture line,the acetabular region was divided into four fracture fragments,and the displacement of each joint in different directions was compared between different groups.(2)According to three groups of different ligament traction acetabular high double column fracture model,the compressive stress on the surface of each bone block was measured.According to the three groups of different ligament traction,displacement nephogram and stress distribution map were analyzed by finite element method.The traction effect of each group of ligament on acetabular fracture was visually reflected.Results Part ?:The traction of acetabular both-column fractures in 30 patients was improved to varying degrees under preoperative and intraoperative anesthesia,and there were still unacceptable displacements.According to the theory of laying equal stress on both bones and tendons",the failure of traction reduction may be related to the location of tendons and muscles attachment point,the shape of attachment point,and the combination of bone injury and tendon injury.After traction reduction failure,30 patients were finally treated with open reduction.All fractures healed well within 2 to 4 months,with an average time of 3.5 months.The quality of fracture reduction was evaluated according to Matta evaluation criteria:excellent in 16 cases,good in 9 cases,fair in 3 cases and poor in 2 cases.At the last follow-up,the imaging results were evaluated according to Matta evaluation criteria:excellent in 15 cases,good in 10 cases,fair in 4 cases and poor in 1 case.The excellent and good rate was 83.3%.At the last follow-up,according to Harris score,modified Merle d'Aubigne and Postal functional score,the average Harris score of 30 patients was 91.6,and the average modified Merle d Aubigne and Postal functional score was 16.7.Open reduction via ilioinguinal approach combined with DAPSQ internal fixation is a safe and effective final treatment for acetabular both-column fractures.Part ?;In 25 cases,the round ligament of the femoral head originated from the transverse acetabular ligament and was divided into anterior and posterior bundles toward the femoral head concave.The anterior bundle was divided into two bundles marked by depression.The depression was temporarily named Cai's fossa.The posterior bundle,centered around the transverse acetabular ligament,attaches to the horseshoe fossa of the acetabulum and covers the horseshoe fossa of the acetabulum like a sucker,ending at the femoral head concave.The length of the round ligament of the femoral head was(24.8 +3.8)mm.Histological results after HE staining showed that the round ligament of femoral head was composed of collagen,adipose tissue,synovial tissue and blood vessels.Part ?:In three groups of high acetabular both-column fracture models with different ligament traction,the results of one-way ANOVA analysis showed that in the X-axis direction,the average displacement of each node of the fracture line between the posterior part of square area and the sciatic branch(posterior column)and the anterior part of square area and the superior pubic ramus in group A,B and C had significant difference(P<0.05).Compared with LSD test,there was no significant difference in average displacement between the posterior part of square area and the sciatic branch(posterior column)and the anterior part of square area and the superior pubic ramus fracture line in group A and B(P>0.05),but The average displacement of each node of the fracture line between the posterior part of square area and the sciatic branch(posterior column)and the anterior part of square area and the superior pubic ramus in group A and group B were significantly larger than those in group C(P<0.05),Because the round ligament of femoral head exists in group A and group B,while group C only has iliofemoral ligament,pubicfemoral ligament,ischiofemoral ligament and articular capsule,so considering that the round ligament of femoral head can significantly restore the traction of acetabular fracture along the femoral neck direction,in the Y-axis direction,there was no significant difference in the average displacement between the posterior part of square area and the sciatic branch(posterior column)and the anterior part of square area and the superior pubic ramus fracture line in group A and C(P>0.05),but the average displacement of each node of the fracture line between the posterior part of square area and the sciatic branch(posterior column)and the anterior part of square area and the superior pubic ramus in group A and C was significantly larger than that in group B(P<0.05).Iliofemoral ligament,pubicfemoral ligament,ischiofemoral ligament and articular capsule had significant repositioning effect on the traction of acetabular fracture fragments along the anterior and posterior edges of acetabulum;there was no significant difference in the mean displacement between the posterior part of square area and the sciatic branch(posterior column)and the anterior part of square area and the superior pubic ramus fracture line(P>0.05);therefore,the traction effect of that ligament on the Z-axis direction could not be predict Better.The results of one-way ANOVA showed that there was significant difference in the average displacement of each node of the fracture line between the acetabular top and the anterior part of the square area and the superior pubic branch in group A,B and C in the X-axis direction(P<0.05).Compared with the LSD test,there was no significant difference in the mean displacement of the acetabular top,the anterior part of the square area and the superior pubic branch fracture line between group A and group B(P>0.05),The average displacement of each node of the fracture line between the acetabular top and the anterior part of square area and the superior pubic ramus in group A and B was significantly greater than that in group C,and the difference was statistically significant(P<0.05).Because the femoral head round ligament exists in group A and group B,while group C only has iliofemoral ligament,pubiofemoral ligament,ischiofemoral ligament and articular capsule,the femoral head round ligament has obvious reposition effect on the traction of acetabular fracture along the femoral neck direction?In the Y-axis direction,there was no significant difference in the average displacement of each node of the fracture line between the acetabular top and the anterior part of square area and the superior pubic ramus in group A and C(P>0.05),but In group A and C,the average displacement of each node of the fracture line between the acetabular top and the anterior part of square area and the superior pubic ramus was significantly greater than that in group B(P<0.05).The iliofemoral ligament,pubicfemoral ligament,ischiofemoral ligament and articular capsule had significant repositioning effect on the traction of acetabular fracture blocks along the anterior and posterior edges of the acetabulum.In the Z-axis direction,there was no significant difference in the average displacement of each node of the fracture line between the acetabular top,the anterior part of square area and the superior pubic ramus in the three groups(P>0.05).Therefore,it can not be predicted that the ligament traction in the Z-axis direction is better.The three groups of acetabular compressive stress distribution maps showed that the maximum compressive stress of the acetabulum was most concentrated in the acetabulum horseshoe fossa(acetabulum square area).It was presumed that traction mainly acted on the reduction of this area.Because the compressive stress of the fixed bone increased due to the restraint effect in this experiment,it was not included in the final result analysis.The acetabular compressive stress distribution in three different models showed that in group A and group B,the compressive stress of the posterior part of square area and the sciatic branch(posterior column),the anterior part of square area and the superior pubic ramus was similar,and was larger than that of group C;and the compressive stress of the top surface of the acetabulum was similar in three groups.The compressive stress on the top of the acetabulum in the same group of models was small,and the predictive traction effect was not good.The compressive stress of the posterior part of square area and the sciatic branch(posterior column)and the anterior part of square area and the superior pubic ramus in the same group of traction is relatively large,and the difference is not significant.It is predicted that traction may have a better effect on the reduction of the posterior part of square area and the sciatic branch(posterior column),the anterior part of square area and the superior pubic ramus.Conclusions Preoperative and intraoperative traction can reduce acetabular both-column fractures to a certain extent,but it is still difficult to achieve satisfactory results.Tendon injury after fracture may be the cause of traction failure.Open reduction via ilioinguinal approach combined with DAPSQ internal fixation is a safe and effective final treatment for acetabular both-column fractures.As the only connection between the acetabulum and the femoral head,the circular ligament of the femoral head has special attachment position and shape on the acetabulum,and has strong potential mechanical properties.It has the structural characteristics of traction reduction of acetabulum fracture.Iliofemoral ligament,pubicfemoral ligament,ischiofemoral ligament and articular capsule have good traction effect on acetabular fracture fragments along the anterior and posterior edges of acetabulum,while femoral head round ligament has good traction effect on acetabulum fracture fragments along the internal and external directions.Traction has the best effect on the area of acetabular anterior and posterior column moving into pelvic cavity,which is equivalent to the square area of acetabulum.The effect of traction on the lower part of acetabulum may be better than that on the upper part of acetabulum.The reason of poor traction effect in some areas after fracture may be bone injury combined with tendon injury.