Application Of China-LISS And Assembled Bolt-Tightrope System In Lower Limb Trauma

With the progress of the modern biological osteosynthesis, the concept ofminimal invasive technology had deeply rooted in the brain of orthopedicsurgeons. Nowadays, the most popular and fashionable fixture for minimallyinvasive internal fixation is the Less Invasive Stabilization System (LISS). Ithad achieved excellent and good treatment effect in treating lower extremityfracture comparing with the traditional fixture. However, this device hadintricated structure and complicated operation procedure with long learningcurve and high price, and using it to achieve a sound and precise fixation offracture is not a easy thing. All these drawbacks of LISS had limited itsextensive clinical application to some extent. To overcome these problems, wehad designed a U-grooved locking compression plate (U-LCP) which wascharactered as a ‘U’ shaped groove at each end of the plate. The minimallyinvasive plate osteosynthesis (MIPO) technique can be achieved by using twoidentical U-LCPs and two positing wires (2.0mm in diameter). The samegood clinical outcomes of U-LCP as that of LISS in treating tibia and fibulafractures had been identified in our previous study. Future more, this U-LCPsystem had simple and quick procedure with shorter learning curve and couldachieve sound and precise fixation of fracture with less trauma and lowerexpense. Because our fixation system could be seen as a simplified LISS, sothe foreign orthopedic peers called it China-LISS. In this prospective study,we compared the treatment effect of China-LISS and LISS in treating thedistal femoral fractures.The predecessor of the China-LISS plate is LCP. However, China-LISSdid not change the main structure of plate body. It just added a U-shapedpositioning groove at each end of the plate to make it possess more functions.In fact, there are some defects on the body of the plate. We found that almost all plate breakage took place at the site of plate hole near fracture area whenwe analyzed the causes of hardware failure cases of both LCP and China-LISSin our hospital. Some literature also reported this phenomenon. This showedus that hole area is the weakest and stress concentration part of the plate andnaturally becomes the site to be improved. So in this study, we broadened theChina-LISS merely at the hole area to make it be stress decentralizedChina-LISS to enhance the plate strength and decentralize the stress transferthere in order to reduce plate breakage. Biomechanical properties of the twoplates were performed and compare. Result showed that stress decentralizedChina-LISS plate would provide greater stiffness and strength, and longerfatigue life than China-LISS plate. Clinical study was then carried out tocompare the clinical efficacy of the two plates in treating lower extremityfractures to investigate whether stress decentralized China-LISS plate cansignificantly reduce the incidence of plate breakage.Part1Comparison of China-LISS plate and LISS plate for treatment ofdistal femoral fracture.Objective： To evaluate and compare the clinical and radiologicaloutcomes of China-LISS plate and LISS plate system.Methods：Between April2010and January2012,65consecutive patientswho had65distal femoral fractures were involved in this study and treatedrandomly either with LISS plate or China-LISS plate by MIPO fashion.Inclusion criteria were skeletally mature patients (>18years old) with AO typeA2, A3and C1-3fracture. Exclusion criteria included open fracture,periprosthetic fracture and those suffering ipsilateral proximal or mid-shaftfemoral fractures patients. All involved patients were administrated by tibialtubercle traction. Operation was performed only when wrinkle sign appeared.Patients are placed supine after general anesthesia or continuous spinalanesthesia with muscle relaxation was administrated. Tourniquet was used inall patients. For AO type A fractures, close reduction technique was used andstandard anterolateral approach was performed. For AO type C fractures,anterolateral parapatellar approach was utilized and the femoral condyles were reduced and fixed under direct vision, while the supracondyle fracture wasclosely reduced and fixed. Patient was operated either with China-LISS orLISS plate technique. Rehabilitation with quadriceps setting exercise wasinitiated after surgery. Active physical therapy and continuous passive motion(CPM) was started after removal of the drains. Straight leg-raising exerciseand active flexion of the knee was encouraged after patient’s discharge. Noweight bearing of the injuried leg was permited during this period of time.Progressive partial weight bearing was recommended if only radiographicevidence of callus appeard on plain films. Full weight bearing was allowedwhen at least three cortices of the fracture site were confirmed consolidationon radiographs. Patients were called back for follow-up at4-week intervalsuntil fracture union and thereafter every3months for1year. At eachfollow-up, anteroposterior (AP) and lateral radiographs were taken andclinical examinations were performed. Functional assessment was performedusing the modified Hospital for Special Surgery (HSS) scoring system at thelast follow-up. Demographic information, perioperative parameters,postoperative parameters and HSS scores were recorded. Data werestatistically analysed using SPSS19.0(SPSS Inc., Chicago, IL, USA). P-value<0.05was considered statistically significant.Results：Sixty-three patients obtained full stage follow-up, including30ones treated with China-LISS Plate and33ones with LISS plate, except onefemale patient treated with LISS plate died for other disease irrelative tofracture and operation at3months after discharged from hospital and anotherpatient lost connection after the first follow-up. There was no difference ingender, side, age, fracture type and injury mechanism of patients between thetwo groups.The pre-operative time and blood loss were similar between the twogroups. However, the operative time, fluoroscopic time and incision length ofthe China-LISS plate group were shorter than that of the LISS plate group.The median of follow-up time was16months for both China-LISS plateand LISS palte group. No difference was found. The union time, range of knee joint motion and HSS scores were similar between the two groups.Nevertheless, the expenditure for hardware of China-LISS plate was much lessthan that of LISS plate (1893.4VS4397.6dollars, P<0.000). No significantcomplications were found in both groups. Seen from the value, China-LISSplate group seemed to have a lower complication rate (13.3%versus24.2%),but no statistical difference were found (P=0.271). However, the complicationtypes were different between the two groups.In China-LISS plate group, one patient with diabetes developedsuperficial infection at4days postoperatively and the infection finallysubsided after careful wound dressing, antibiotic therapy, radiofrequencyhyperthermia and rigorous control of blood glucose level. One patient hadvalgus deformity about5degrees and one had varus deformity under5degrees. One patient suffered delayed union. This patient was treatednon-operatively and finally the fracture union was achieved at7.5monthspostoperatively.In LISS plate group, one patient developed hematoma at the fracture siteafter operation which was managed by operation cleaning. One patientappeared varus deformity under5degrees and one valgus deformity of10degrees. In2patients, anterior malposition of the plate on the femur was found.Fortunately, no screw cutting-out and failure of fixation was developed. Twopatients had skin irritational symptom for LISS plate at the lateral distal femur.However, no patient complained it caused severe impact to the knee jointmotion and the symptom disappeared in all patients after hardware removal.One aged male patient also developed delayed bone union in this group. Hewas also treated non-operatively and the fracture united at8monthspostoperatively.Conclusion：China-LISS plate achieve the same good result as LISSplate in treating distal femoral fracture with less expenditure and shorterlearning curve. It is more suitable to be applied in undeveloped anddeveloping regions. Part2Biomechanical comparison of stress decentralized China-LISSplate versus China-LISS plate for fixation of comminuted tibial shaftfractureObjective： To compare monotonic biomechanical properties stressdecentralized China-LISS plate with China-LISS plate of human tibial shaft ingap fracture mode.Methods：Twenty paired fresh cadaveric human tibias were randomlydivided into4groups (5pairs each):(1) axial loading single cycle to failuretesting,(2) torsion single cycle to failure testing,(3)4-point bending singlecycle to failure testing and (4) dynamic4-point bending testing. A7-hole4.5mm stress decentralized China-LISS plate was secured on the anteromedialsurface of1randomly selected bone from each pair, respectively, using6locking screws in the1st,2nd,3rd,5th,6th and7th hole with the middle holeunfilled and just located at the mid-diaphysis of the tibia. A7-hole4.5mmChina-LISS plate was secured on the other bone with the same method.Standard AO/ASIF techniques were used. After fixation finished, a10mmgap in the mid-diaphysis of tibia was created, centrally located at the unfilledhole. The axial, torsional, and bending stiffness and failure strengths werecalculated from the collected data in static testings and statistically comparedusing paired Student’s t-test. The4-point bending fatigue lives of the twoconstructs were calculated from the dynamic testing data and also statisticallycompared using paired Student’s t-test. Failure modes were recorded andvisually analyzed. P<0.05was considered significant.Results：The axial, torsional and bending stiffness of stress decentralizedChina-LISS plate construct was greater (4%,19%,12%, respectively, P<0.05)than that of the China-LISS plate construct, and the axial, torsional andbending failure strengths of stress decentralized China-LISS plate constructwere stronger (10%,46%,29%, respectively, P<0.05) than those of theChina-LISS plate construct. Both constructs failed as a result of plate plastictorsional deformation. After axial loading and4-point bendingtestings,China-LISS plate failed in term of an obvious deformation of bentapex just at the unfilled plate hole, while the stress decentralized China-LISS plate failed in term of a deformation of bent arc between the3rd and5th holes,which indicated a more consistent stress distribution on stress decentralizedChina-LISS plate. Fatigue life of stress decentralized China-LISS plateconstruct was significantly greater than China-LISS plate construct (153836±2228vs.132471±6460cycles, P<0.01). All constructs failed as a resultof fracture of the plate through the compression hole of the unfilledcombination screw hole. The biomechanical testing showed that stressdecentralized China-LISS plate can provide greater stiffness and strength, andlonger fatigue life than China-LISS plate.Conclusion：The stress decentralized China-LISS plate may be moreadvantageous mechanically and may reduce the plate breakage rate clinically.Part3Comparison of the clinical effect of stress decentralizedChina-LISS plate and China-LISS plate in treating of tibia fractureObjective： To compare the clinical effect of stress decentralizedChina-LISS plate and China-LISS plate in treating of tibia fracture.Methods：Two hundred and seventy patients with tibia fracture fromSeptember,2009to March,2012in our hospital were retrospectively studied,including139of which treated with stress decentralized China-LISS plate and131of which with China-LISS plate. The length of incision, amount of bloodloss, radioactive time, operative time, hospital days，bone healing time,complication rate, and function recovery of the affected limb were collectedand statistically compared.Results: The mean follow-up time was16.8weeks (rang,12-22weeks).The mean length of incision was7.8(rang,6.9-10.1) cm for stressdecentralized China-LISS group and7.6(rang,6.9-10.1) cm for China-LISSgroup (P=0.25). The mean amount of blood loss was65(rang,50-200) ml forstress decentralized China-LISS group and60(rang,40-200) ml forChina-LISS group (P=0.388). The radioactive time was21.46(rang,17-27) sfor stress decentralized China-LISS group and21.45(rang,20-27) s forChina-LISS group (P=0.75). The operative time was75(rang,50-120)minutes for stress decentralized China-LISS group and78(rang,50-110) minutes for China-LISS group (P=0.939). The hospital days was11(rang,8-20) days for stress decentralized China-LISS group and11(rang,8-15) daysfor China-LISS group (P=0.762). The bone healing time was16.5(rang,12.6-22.5) weeks for stress decentralized China-LISS group and16.5(rang,15-22) weeks for China-LISS group (P=0.746). The overall complication ratewas15.1%for stress decentralized China-LISS group and16%forChina-LISS group (P=0.834). There was no difference between the twogroups as to the superficial infection rate, deep infection rate, bone union rate,malunion rate, incidence of hematoma and screw breakage rate. However,stress decentralized China-LISS had significant lower plate breakage rate(P=0.032). The excellent and good rate was93.5%for stress decentralizedChina-LISS group and84.7%for China-LISS group, according to theJohner-Wruhs scoring system (P=0.02).Conclusion: In stress decentralized China-LISS group, patients hadbetter function outcome and lower plate breakage rate.