| PrefaceThe fracture of tibia may account 10 percent in long bone fractures, so itis significance to study on it. According to traffic accident, the high energyand speed injures were increased, the incidence rate of tibia fracture wereupgraded too. In the 60s of 20 centuries, AO/ASIF system overemphasized themechanical fixation in treating fractures, so in most clinical observations,them found the problem of osteoporosis, bone atrophy, bone healing delay,fracture again, et al.BO (Biological Osteosynthesis) technique emphasize the blood supplyingprotection in fractures, the bone can heal in the second stage, so it calledbiological and reasonable fixation. Minimally invaslve plate osteosynthesis(MIPO) is the current progress of BO techniques, it needs no exprosure of theextrem of fractures, and can reduce and fix indirect, so it diminish the destroyof soft tissue and the blood supplying of pericosteum, noninterference theblood circulation of medullary cavity, shorten the operating time, depressedthe bone disunion and infecting, profited the functional rehabilitation, so theclinical therapeutic effection were satisfact. However, in the application of MIPO to treat middle tibia fractures, thelongth of plate, the number and location of fixed screw were no shaped inacademic circles, there were dispute constantly, and those were the key pointwere been solved in our studys.We used cadaver tibia of adults in the test, measure the contructed,retated and 3 pionts curved biomechanical character in middle tibia fractures,compared the different longth of plate (6 holes, 10 holes and 14holes) fixedwith 6 screws, 14 holes of Limited Comtact-Dynamic CompressionPlate(LC-DCP) were fixed with different number of screws ( 6 screws, 10screws and 14 screws), and 14 holes of LC-DCP fixed with 6 screws indifferent locations.In the calculating biomechanical researchs, we advocate using longerplate and less screw fixtion in treating middle tibia fracture, because longerplate can correct revolving and angulating deform, retaine the axle and longthof tibia well. The extend of LC-DCP force arm can increace the number ofstress centralized pionts, less the demands to skeleton, the most important ofall, it add the span between the screws, so it can neutralization the momentstress to the screws, which can pull the screws out accidently.In order to confirm our conclusions, we also designed three dimensionfinite element model of 14 holes LC-DCP were fixed with 14 screws and 6screws fixed in different locations in treating middle tibia fractures, test theircharacters of contructed, retated and 3 pionts curved too, so can provid moredetailed biomechanical witness in treating middle tibia fracture with MIPOtechnique. PART ONEBiomechanical study of MIPO to treat of tibial shaft fracturesObjectives:To research the biomechnical effect of different length bone plates,number and location of stews to treat with the fracture of tibial shaft, providbiomechanical witness to MIPO.Methods:We used 60 humid cadaver tibias of adult ( 20-40 years old ) in theresearch, randomizated them to different groups, measure the contructed,retated and 3 pionts curved biomechanical character in middle tibia fractures,compared the different longth of plate (6 holes, 10 holes and 14holes) fixedwith 6 screws, 14 holes of LC-DCP were fixed with different number ofscrews ( 6 screws, 10 screws and 14 screws), and 14 holes of LC-DCP fixedwith 6 screws in different locations. The contruct power were 0～1 000 N,retate angle were 0～3(?), 3 pionts curved force were 0～400 N. Used SPSS12.0 statistics software to analyze.Results:1,The biomechanical test to the longth of plate to treat with tibial shaftfracture6, 10 and 14 holes plate when vertical compressions, the verticaldirection strain value respectively be 0.449±0.241, 0.093±0.003, 0.139±0.005,10 holes and 14 holes steel plates has statistics significance with 6 steel platecomparison difference (P＜0.01). 10 holes and 14 holes steel plates comparison difference non-statistics significance (P＞0.05). 6, 10 and 14 holes plate are(5.066*10-3±2.715*10-3 ) N·m, (5.671*10-3±2.527*10-3) N·m,(4.570*10-3±2.228*10-3) N·m, three pionts curving vertical direction strainvalue respectively be 0.049±0.009, 0.124±0.017, 0.062±0.009 respectively,between various plate 2-2 comparison differences has statistics significance (P＜0.01).2,The biomechanical test of the number of screws to to treat with tibialshaft fracture6, 10 and 14 screw screws when fixed vertical compressions verticaldirection strain value respectively be 0.120±0.006, 0.111±0.012, 0.116±0.008,2-2 comparison difference non-statistics significance (P＞0.05). 6, 10 and 14screw bolt fixed flank strain value respectively be 0.234±0.007, 0.234±0.000,0.179±0.002, 2-2 comparison difference non-statistics significance (P＞0.05).Three pionts curving vertical direction strain value respectively be0.149±0.098, 0.139±0.003, 0.258±0.001,6 a screw and 10 screws compares,the non-significance difference (P＞0.05), 14 screws and other two kind ofsituation contrasts, have the significance difference (P＜0.01).3,The biomechanical test of the location of screws to to treat with tibialshaft fractureAll of those four groups of vertical compressions the vertical directionstrain value respectively be 0.120±0.006, 0.0330±0.0027, 0.139±0.005,0.116±0.008, the second group has statistics significance with other group ofcontrast difference (P＜0.01). Four group of flank strain value respectively be0.234±0.007, 0.237±0.0006, 0.187±0.002, 0.217±0.002, the third group hasstatistics significance with other group of comparison difference (P＜0.01).Four groups of torques respectively be (7.304*10-3±3.072*10-3) Nm, (6.965*10-3±3.096*10-3)Nm,(4.570*10-3±2.228*10-3)Nm,(2.086*10-3±0.998*10-3) Nm, the third group have statistics significance with other group ofcomparison difference (P＜0.01). Three pionts curving vertical direction strainvalue respectively be 0.149±0.098, 0.184±0.002, 0.004±0.001, 0.282±0.000,the first, second group has statistics significance with other group of 2-2comparison difference (P＜0.01), The fourth group has statistics significancewith other group of 2-2 comparison difference (P＞0.05). First, second groupof 2-2 comparison difference non-statistics significance (P＞0.05).Conclusions:1,Stability of different length of plate with same quality ,samethickness,same width,using same quantity of screw, 14 hole plate is the best,6hole plate is not sogood.2,The material quality is the same, thickness is the same, the width is thesame, the length same steel plate, the use different quantity screws (6, 10, 14),the anti-vertical compression stability, the anti-reverse stability not obviousdifference, the anti-curving stable 14 screws are instead bad.3,Uses the same material quality, the same length, the same width, thesame quantity screws, approaches in the fracture line place screw, theanti-compression stability and the anti-reverse stability are well, but thescrews distributes in the plate both sides, the anti-reverse stability is bad. Boltaverage distribution, anti-curving stability and anti-reverse stable good, but thescrews distributes in the plate both sides, anti-curving, the anti-compression,the anti-reverse stability are bad. PART TWOThree diamensional finite element analysis of MIPO to treat with tibialshaft fracturesObjectives:To determine the biomechnical effect and three diamensional finiteelement model of different number and location of srews to treat with thefracture of tibial shaft, provid more detailed proofs to MIPO.Methods:Select 5 humid cadaver tibias of male adult, made them to middle tibiafratures randomly, oblique shape and with no defece, all models were fixedwith 14 holes of LC-DCP. The first model was fixed in the 1st, 2nd, 3rd, 12th,13th, 14th hole, the second model was fixed in the 1st, 4th, 7th, 8th, 11th,14th hole, the third model was fixed in the 1st, 3rd, 6th, 9th, 12th, 14th hole,the fourth model was fixed in the 1st, 2nd, 7th, 8th, 13th, 14th hole, the fifthmodel was fixed in all holes with 14 screws. Using finite element software ofAnsys 6.5, established the three diamensional finite element model of tibialshaft fratures of those five models above. Computer digital analog loading, thecontruct power were 0～1 000 N, retate angle were 0～3(?), 3 pionts curvedforce were 0～400 N. Measured the stress of all screws and used SPSS 13.0statistics software to analyze.Results:1,In the firsr model fixed in the 1st, 2nd, 3rd, 12th, 13th, 14th hole, the stress of all screws in the X and Y axile, the contruct and retate strains arehighest in the 3rd and 12th hole, and has the tendency of centralized to themiddle of plate. Generally, the stress of all screws are not high, the strain islocated in the middle of the plate.2,In the second model fixed in the 1st, 4th, 7th, 8th, 11th, 14th hole,the stress of all screws in the X, Y and Z axile, the contruct strain is highest inthe 1st hole, and the contruct strain in the 4th hole is secondary, the tendencyof stress distribution reduct from up to bottom. The retate strains in the X, Yand Z axile is the highest in the 7th and 8th holes, it is centralized in themiddle of plate and decrease to both extrem.3,In the third model fixed in the 1st, 3rd, 6th, 9th, 12th, 14th hole, thestress of all screws in the X, Y and Z axile, the contruct strain is highest in the1st hole, and the contruct strain in the 3th hole is secondary, the tendency ofstress distribution reduct from up to bottom. The retate strains in the X, Y andZ axile is the highest in the 6th and 9th holes, it is centralized in the middle ofplate.4,In the fourth model fixed in the 1st, 2nd, 7th, 8th, 13th, 14th hole,the stress of all screws in the X, Y and Z axile, the contruct strain is highest inthe 1st hole, and the contruct strain in the 2th hole is secondary, the tendencyof stress distribution reduct from up to bottom. The retate strains in the X, Yand Z axile is the highest in the 7th and 8th holes, the stress is the lest thanother means of all, the strain distribution is equilibrately.5,In the fifth model fixed in all 14 holes, the stress of all screws in the X,Y and Z axile, the contruct strain is highest in the 1st hole, and the contructstrain in the 2th hole is secondary, the tendency of stress distribution reductfrom up to bottom. The retate strains in the X, Y and Z axile is the highest in the 7th and 8th holes, the stress is centralized in the middle two screws.Conclusions:1,We established the finite element mole of tibial shaft fracture withinternal fixation, it can reflects the ture geometry construction of tibiarealistically.2,This finite element model of tibia fracture with internal fixationprovids a new research means to biomechanical analysis and simulate tests, soit has a favourable applicating prospection.3,When internal fixed with 14 holes plate, fixed with 6 holes and 14holes, the anti-vertical compression stability and the anti-reverse stability arenot obvious difference, but the anti-curving stablility in 14 screws fixed areworse.4,In the treatment of tibia shaft fractures with MIPO technique, fixedwith 6 screws is better than 14 holes, the location of screws is best when fixedin the 1st, 2nd, 7th, 8th, 13th, 14th hole. |
PDF Full Text Request