| Backgroud:In China, with the industrial development, the traffic accidents of incidence of acetabular fractures had increased in the past decade gradually. High-energy injuries brought about pelvis and acetabulum fractures, especially comminuted fracture of acetabular bone defects. According to acetabular of two-column theories could not fully explain the unique phenomenon of children of acetabular fractures. With clinical emerging high-energy injuries and the compound injuries increased, the type of acetabular fractures was more complex. Some new types of fractures have been continuing to emerge, more difficult classification, diagnosis, and the management were appeared than before,As well as surgical treatment-related complications. So the Traditional classification can not be used to report actual fractures. Such as compression defects, complex fractures, multiple hip fractures, combined injuries, etc. The incidence of fracture and the injury severity of the outcome made a challenge for its treatment. Also some scholars have stressed:the complexity of acetabular fractures, leading to fracture type of infinity.In view of the above reported,our team members Zhang Chuncai professor proposed new theoies innovatively:acetabular and its floating classification,accroding to the acetabulum of embryology, anatomy, and mechanics. The Anterior column from the ear-shaped surface extending along the arcuate line forward by iliopubic eminence and reach the superior ramus of pubis symphysis pubis; The middle column extends upward from the acetabular roof and the front of the iliac tubercle, iliac fossa living in thin pre-cortical bone; The posterior column,which was in the of thin cortical iliac fossa bone of the rear, from the latter half of iliac crest through the sciatic notch to reach large ischial tuberosity. From the pelvis the front view, the middle column was between other two-column,and the three-column maintained the shape of the acetabulum. The middle column,that the acetabulum of the pelvis acetabular roof was a specialized structure of the human body, whose's existence was closely related to human features of walking upright and formed from the long-term evolution of ape to man gradually.Which constitute an integral part of the acetabulum and played an important role in maintaining the stability of the hip joint. Therefore, we need to make a research for acetabular pelvic structure and function, According to physiological functions and characteristics of the new regional division, and on the base of the acetabular part of the organizational structure made a proof from the anatomy and bimechanics.Objective:1,To quantitatively measure the normal acetabular bone articular surface area, revealed the acetabular articular surface of the column and to explore the column shape characteristics and clinical significance of the acetabular articular surface of the column.2,To simulat the hip join stree of the different human gait cycle and made a test for conduct stress. To detect the pelvis acetabulum and the femoral head between the various measuring points biomechanical changes and analyze the load stress distribution.3,Able to find the consistency of the acetabular part of the structure and load distribution, provide a strong theoretical basis for acetabular region for the new division separation (three-column acetabulum), In order to provide new theoretical reference for clinical treatment.Methods:1,In the 52 hip, the use of gypsum shaping acetabular articular surface, flatten into a two-dimensional diagram tracing, respectively, numerical quadrature, and computer software to measure Photoshop7.0 observation, validation of analytical results.2,There were 5 new semi-pelvic osteotomy and proximal femur 1/3 specimens, using clamps to maintain the pelvis and simulating different phases of the gait, such as Single foot support, toe off, heelstrike. To made mechanical load in the WE-100 hydraulic universal, and be thoroughly set before the test 100N, then 200N of force increase, grading load 800N, loading rate control 1.50mm/min, using KG-101 significantly high-precision optical displacement sensors and the dial gauge to measure simulataneously, and then fixed the pressure sensitive film into the hip between femoral head and acetabulum of the mechanics of the column in the mechanical test.Results:1,The articuar surface is progessive in the middle column,the posterior column and anterior column, the ratio was 4.1:2.8:1.By Planimeter,the acetabular surface area was 25.45±2.81 cm2, of which articular surface of anterior column was 3.21±0.64 cm2, articular surface of the middle column (acetabular roof weight-bearing area) was 13.13±1.86 cm2,and the articular surface of the posterior column was 9.13±1.79 cm2;By Photoshop7.0,the acetabular articular surface area was 25.43±3.04 cm2, of which articular surface of anterior column 3.19±0.68 cm2, the articular surface of middle column 13.08±2.16 cm2, the articular surface of posterior column 9.15±1.76 cm2.There was no significant different in the column articular surface mearsured by these different mearsments.(P>0.05).Male:the acetabular articular surface area was 26.28±2.22 cm2 of which articular surface of anterior column 3.26±0.71 cm2, the articular surface of middle column was 13.64±1.73 cm2, the articular surface of posterior column was 9.38±1.48 cm2.Female:The acetabular articular surface area was 24.38±3.34 cm2. of which articular surface of anterior column was 3.13±0.58 cm2, the articular surface of middle column was 12.42±2.14 cm2, the articular surface of posterior column was 8.85±2.05 cm2.There was no significant different between the anterior column and the posterior (P> 0.05),the statistical results showed that data of male more than those of feman in the acetabular articular surface area and the articular surface of middle column (P<0.05).Right:The acetabular articular surface area was 25.41±2.86 cm2, of which articular surface of anterior column 3.22±0.59 cm2, the articular surface of middle column 13.01±1.69 cm2, the articular surface of posterior column was 9.19±1.57 cm2.Left:The acetabular articular surface area was 25.47±2.99 cm2, of which articular surface of anterior column 3.19±0.72 cm2, the articular surface of middle column was 13.19±2.28 cm2, the articular surface of posterior column was 9.11±1.94 cm2.There was no different significant differents in sides between left and right (P>0.05).2,To simulate the hip join stree of the different human gait cycle and made a test for conduct stress.To detect the points biomechanical changes between the acetabulum and the femoral head and analyze the load stress distribution.①The pression between the acetabulum and the femoral head in the single support phase.The human body is a typical one of the human body posture in single surport state.The pression between the acetabular and femoral head was about 2.75w.Meanwhile, the articular surface of the middle column (acetabular roof weight-bearing area)pressure was 1.72±0.34mpa,the articular surface of anterior column was 1.41±0.35mpa, and the articular surface of the posterior column was 1.31±0.30 mpa, the articular surface of the middle column (acetabular roof weight-bearing area)peek prssure was 1,72±0.34mpa.The results showed that the articuar surface is progessive in the middle column,the posterior column and anterior column.these was no significant differents between the anterior and middle column (P>0.05),meanwhile significant differents between the posterior and middle column (P<0.05)②The pression between the acetabulum and the femoral head in the toe off phase.The articular surface of the middle column (acetabular roof weight-bearing area)pressure was 3.65±0.26mpa,the articular surface of anterior column was 3.03±0.24mpa, and the articular surface of the posterior column was 2.80±0.23mpa, the articular surface of the middle column (acetabular roof weight-bearing area)peek prssure was 6.17±0.31mpa.The results showed that the articuar surface is progessive in the middle column,the posterior column and anterior column.these was significant differents between the anterior and middle column (P<0.01),meanwhile significant differents between the posterior and middle column (P<0.01).The three-column contact stress significantly increased peak contact stress more quickly, the human gait when the acetabular articular surface on the contact load dynamics under the action of the state belong to the hip joint load, in the gait cycle, toe off and heelstrike from the ground when two peak joint loads appeared③The pression between the acetabulum and the femoral head in the heelstike phase. The articular surface of the middle column (acetabular roof weight-bearing area)pressure was 2.58±0.25mpa,the articular surface of anterior column was 2.10±0.15mpa, and the articular surface of the posterior column was 1.72±0.19mpa, the articular surface of the middle column (acetabular roof weight-bearing area)peek prssure was 3.89±0.31mpa.The results showed that the articuar surface is progessive in the middle column,the posterior column and anterior column.these was significant differents between the anterior and middle column (P<0.01),meanwhile significant differents between the posterior and middle column (P<0.01)Conclusion:1,The articuar surface is progessive in the middle column,the posterior column and anterior column.The weight-bearing region plays an important role in maintaining the integrity of the stability of the hip,and it is of great significance for the evaluation of acetabular trauma prognosis.2,Between femoral head and acetabulum contact area, these was maximum contact pressure in the roof area of the acetabulum,which showed that the pressure in the roof area of acetabular was high stress state, and the largest force of cortical and cancellous part were consistent. There was pressure appearing in the roof area of the acetabular in the gait(single foot surpport, toe off, heelstike),as well as peek pressue. It is confirmed that The weight-bearing region plays an important role in maintaining the integrity of the stability of the hip.3,It is confirmed that the central column of acetabulum (acetabular roof) structure and distribution of load stresses unity from the anatomical and biomechanical measurements, and provided a new theoretical basis for the new division of the region of acetabulum (acetabular three columns) and theoretical reference for clinical treatment. |
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