Dissertations / Theses on the topic 'Femoral fracture fixation'

Femoral fracture in adolescents is a severe injury. Recent studies of intramedullary nail fixation with rigid titanium alloy helical nail viz. Expert adolescent lateral femoral nail (ALFN) have reported good results. However, there is no in vitro biomechanical data available on this nail in the literature. Experimental testing and finite element analysis (FEA) were used to establish the stiffness parameters of small composite femurs with simulated fractures stabilised using ALFN. In comparison to intact femur, construct stiffness ranged from maximum (114%) to minimum (20%) for healed fracture and segmental fracture, respectively. Simulation testing in SolidWorksTM was performed with validated FEA model to evaluate the effect of clinical and implant factors. Maximum predicted stress in the distal interlocking screw remained in an acceptable range (160.25 - 188.51 MPa) irrespective of the level of femoral shaft fracture with a relative decrease in stress values as the fracture callus healed over a 16 week period. The relative angle between the ALFN and proximal interlocking screw and implant material were two significant factors influencing stress at the interlocking screw and nail interface. In conclusion, a rigid helical titanium alloy femoral intramedullary nail can perform satisfactorily under physiological loading conditions experienced in the perioperative period.

Periprosthetic femoral fractures (PFF) are a complication associated with total hip arthroplasty patients that can be both traumatic and challenging to treat. With the increasing age of the population and increasing prevalence of hip replacement surgery periprosthetic femoral fractures are expected to occur more frequently in the future. The most common type of PFF is the Vancouver Type B fracture that occurs near the tip of the original prosthesis. These fractures can be complicated further by loosening of the primary femoral stem (Type B2 fractures) and poor bone stock (Type B3 fractures). Clinical failures and unclear optimal treatment recommendations for many fractures suggest that further investigation is required. This study mechanically tested experimental specimens representing the cemented long stem revision treatment of a Type B2 PFF at a range of loading orientations to evaluate their biomechanical response. From these specimens the axial stiffness, medial axial strain, distal lateral axial strain, and relative fracture movement were recorded under semi-physiological loading. These experimental results were also used to validate computational, finite element (FE), models of long stem PFF treatment. The computational models were shown to achieve reasonable agreement with the experimental data, such that they could be used to investigate a wider range of clinical scenarios. The FE models were then used to compare the relative effects of different cement mantle geometries, fracture location, fracture bridging distance, fracture angle, revision femoral stem length and osteoporosis. The specific location and angle of the fracture appeared to have an effect on the bending response of the femur and the optimal treatment. Long stem revision treatment however seemed to be suitable for achieving stability around an unstable fracture and it may be possible to counter-act the increased risk of fixation failure in osteoporotic patients by selecting a longer bridging distance.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
The Ibandronate sodium is a drug used for clinical treatment of osteoporosis and for anti-catabolic action and cause osteoclast apoptosis, an important cell responsible for bone remodeling, it was hypothesized an effect on fractures in the consolidation phase of callus remodeling.The aim of this study was to evaluate the effect of ibandronate sodium in the fracture of femurs of rats subjected to intramedullary fixation. This study used 48 adult male rats, Wistar, with the average weight of 336.63 g. All animals underwent surgery for intramedullary osteosynthesis of the right femur and subsequently performed a standardized fracture. They were divided into two groups: the ibandronate, which was administered a single dose of 15mg/kg by gavage and the control group was administered a single dose of 1.0 ml of 0.9% saline by gavage also on the same day of the procedure surgery. At 7, 14, 28 and 42 days postoperatively six animals from each group were euthanized and the femurs were subjected to X-ray study to analyze the optical density and area of callus and histological study, using samples stained with picrosirius red and analyzed under polarized light, to quantify the density of collagen type I and type III in the cortical region near the fracture and callus. The radiographs showed that the area of the callus showed no statistically significant differences between groups control and ibandronate, but in the intragroup analysis 28 and 42, the callus was significantly higher on day 7 in both groups. The optical density of intergroup evaluation showed that ibandronate group at day 42, showed a higher density than the control group. In the study of collagen in the callus, the density of type I collagen seen in the ibandronate group was higher than that observed in the control group on days 7 and 14, since the density of type III collagen found in the ibandronate group was lower than in the 7 days Control group. In the study of collagen in the cortex, collagen type I in the ibandronate group was significantly greater on day 7 than the control group and type III collagen in the ibandronate group was lower than the Control group. The results are consistent enough to say that this drug has an effect on bone fracture healing by increasing the density of type I collagen in the early stages of consolidation.
O Ibandronato de sÃdio à um medicamento utilizado para o tratamento clÃnico da osteoporose e por ter aÃÃo anticatabÃlica e causar apoptose no osteoclasto, uma importante cÃlula responsÃvel pela remodelaÃÃo Ãssea, foi hipotetizado um efeito na consolidaÃÃo fraturas na fase de remodelaÃÃo do calo Ãsseo. O objetivo deste estudo foi avaliar o efeito do ibandronato de sÃdio na consolidaÃÃo das fraturas de fÃmures de ratos submetidos à osteossÃntese intramedular. Neste estudo foram utilizados 48 ratos machos, adultos, da linhagem Wistar, com o peso mÃdio de 336,63g. Todos os animais foram submetidos a procedimento cirÃrgico para osteossÃntese intramedular do fÃmur direito e posteriormente realizado uma fratura padronizada. Eles foram divididos em dois grupos: o grupo Ibandronato, em que foi administrada dose Ãnica de 15mg/Kg por gavagem e o grupo controle foi administrado dose Ãnica de 1,0ml de soluÃÃo fisiolÃgica 0,9% tambÃm por gavagem, no mesmo dia do procedimento cirÃrgico. No 7Â, 14Â, 28 e 42 dia de pÃs-operatÃrio seis animais de cada grupo eram eutanasiados e os fÃmures foram submetidos a estudo radiogrÃfico para analisar a densidade Ãptica e Ãrea do calo Ãsseo e estudo histolÃgico, utilizando amostras coradas com picrosirius red e analisadas sob a luz polarizada, para quantificar a densidade de colÃgeno tipo I e tipo III na regiÃo cortical prÃxima a fratura e no calo Ãsseo. A anÃlise das radiografias mostrou que a Ãrea do calo Ãsseo nÃo apresentava diferenÃas estatisticamente significantes entre os grupos Controle e Ibandronato, mas que na anÃlise intragrupo os dias 28 e 42 o calo era significantemente maior que no dia 7, em ambos os grupos. A densidade Ãptica na avaliaÃÃo intergrupos mostrou que o grupo Ibandronato, no 42 dia, apresentava uma maior densidade que o grupo controle. No estudo do colÃgeno no calo Ãsseo, a densidade do colÃgeno tipo I verificada no grupo Ibandronato foi maior que a observada no grupo Controle nos dias 7 e 14, jà a densidade de colÃgeno tipo III verificada no grupo Ibandronato foi menor no dia 7 que no grupo Controle. No estudo do colÃgeno da cortical prÃxima ao foco de fratura, o colÃgeno tipo I no grupo Ibandronato foi significantemente maior no dia 7 que o grupo controle e o colÃgeno tipo III no grupo Ibandronato foi menor que o grupo Controle. Os resultados encontrados sÃo consistentes o suficiente para afirmar que este fÃrmaco exerce efeito na consolidaÃÃo de fraturas Ãsseas aumentando a densidade do colÃgeno tipo I nas fases iniciais da consolidaÃÃo.
O Ibandronato de sÃdio à um medicamento utilizado para o tratamento clÃnico da osteoporose e por ter aÃÃo anticatabÃlica e causar apoptose no osteoclasto, uma importante cÃlula responsÃvel pela remodelaÃÃo Ãssea, foi hipotetizado um efeito na consolidaÃÃo fraturas na fase de remodelaÃÃo do calo Ãsseo. O objetivo deste estudo foi avaliar o efeito do ibandronato de sÃdio na consolidaÃÃo das fraturas de fÃmures de ratos submetidos à osteossÃntese intramedular. Neste estudo foram utilizados 48 ratos machos, adultos, da linhagem Wistar, com o peso mÃdio de 336,63g. Todos os animais foram submetidos a procedimento cirÃrgico para osteossÃntese intramedular do fÃmur direito e posteriormente realizado uma fratura padronizada. Eles foram divididos em dois grupos: o grupo Ibandronato, em que foi administrada dose Ãnica de 15mg/Kg por gavagem e o grupo controle foi administrado dose Ãnica de 1,0ml de soluÃÃo fisiolÃgica 0,9% tambÃm por gavagem, no mesmo dia do procedimento cirÃrgico. No 7Â, 14Â, 28 e 42 dia de pÃs-operatÃrio seis animais de cada grupo eram eutanasiados e os fÃmures foram submetidos a estudo radiogrÃfico para analisar a densidade Ãptica e Ãrea do calo Ãsseo e estudo histolÃgico, utilizando amostras coradas com picrosirius red e analisadas sob a luz polarizada, para quantificar a densidade de colÃgeno tipo I e tipo III na regiÃo cortical prÃxima a fratura e no calo Ãsseo. A anÃlise das radiografias mostrou que a Ãrea do calo Ãsseo nÃo apresentava diferenÃas estatisticamente significantes entre os grupos Controle e Ibandronato, mas que na anÃlise intragrupo os dias 28 e 42 o calo era significantemente maior que no dia 7, em ambos os grupos. A densidade Ãptica na avaliaÃÃo intergrupos mostrou que o grupo Ibandronato, no 42 dia, apresentava uma maior densidade que o grupo controle. No estudo do colÃgeno no calo Ãsseo, a densidade do colÃgeno tipo I verificada no grupo Ibandronato foi maior que a observada no grupo Controle nos dias 7 e 14, jà a densidade de colÃgeno tipo III verificada no grupo Ibandronato foi menor no dia 7 que no grupo Controle. No estudo do colÃgeno da cortical prÃxima ao foco de fratura, o colÃgeno tipo I no grupo Ibandronato foi significantemente maior no dia 7 que o grupo controle e o colÃgeno tipo III no grupo Ibandronato foi menor que o grupo Controle. Os resultados encontrados sÃo consistentes o suficiente para afirmar que este fÃrmaco exerce efeito na consolidaÃÃo de fraturas Ãsseas aumentando a densidade do colÃgeno tipo I nas fases iniciais da consolidaÃÃo.
The Ibandronate sodium is a drug used for clinical treatment of osteoporosis and for anti-catabolic action and cause osteoclast apoptosis, an important cell responsible for bone remodeling, it was hypothesized an effect on fractures in the consolidation phase of callus remodeling.The aim of this study was to evaluate the effect of ibandronate sodium in the fracture of femurs of rats subjected to intramedullary fixation. This study used 48 adult male rats, Wistar, with the average weight of 336.63 g. All animals underwent surgery for intramedullary osteosynthesis of the right femur and subsequently performed a standardized fracture. They were divided into two groups: the ibandronate, which was administered a single dose of 15mg/kg by gavage and the control group was administered a single dose of 1.0 ml of 0.9% saline by gavage also on the same day of the procedure surgery. At 7, 14, 28 and 42 days postoperatively six animals from each group were euthanized and the femurs were subjected to X-ray study to analyze the optical density and area of callus and histological study, using samples stained with picrosirius red and analyzed under polarized light, to quantify the density of collagen type I and type III in the cortical region near the fracture and callus. The radiographs showed that the area of the callus showed no statistically significant differences between groups control and ibandronate, but in the intragroup analysis 28 and 42, the callus was significantly higher on day 7 in both groups. The optical density of intergroup evaluation showed that ibandronate group at day 42, showed a higher density than the control group. In the study of collagen in the callus, the density of type I collagen seen in the ibandronate group was higher than that observed in the control group on days 7 and 14, since the density of type III collagen found in the ibandronate group was lower than in the 7 days Control group. In the study of collagen in the cortex, collagen type I in the ibandronate group was significantly greater on day 7 than the control group and type III collagen in the ibandronate group was lower than the Control group. The results are consistent enough to say that this drug has an effect on bone fracture healing by increasing the density of type I collagen in the early stages of consolidation.

In the pool of women over the age of 50, the likeliness of an atypical fracture increase drastically, partly due to osteoporosis. With a pre-existing implant in the femur bone, inserted due to a prior atypical fracture, treating a later femoral neck fracture is complex and risky. Currently, a fractured femoral diaphysis is treated using an intermedullary nail which is fixed to the femur bone either through the femoral neck (Recon locking method)or through the lesser trochanter (Antegrade locking method). In a study conducted by Bögl et.al. JBJS102.17 (2020), pp. 1486-1494, it is found that the fixation of the intermedullary nail through the femoral neck reduces the risk of future femoral neck fractures. The study also states that more than 50% of the patients with atypical femoral fractures related to bisphosphonate treatment for osteoporosis (within the study sub population) were treated with the Antegrade locking implant. There does not exist much literature that reasons as to how one locking method is showing lesser risk of re-operation as compared to the other. The purpose of this study is to look into the effects these two implants have on the femur bone using the Finite Element Analysis (FEA). The study presented is aimed at comparing the results of the finite element analysis for the Recon implant model (Recon model) and Antegrade implant model (Antegrade model). The femur model without the implants (native bone model) is used to verify material behavior, while the other two are used for the comparison to study the stress-strain distribution, primarily in the neck region. This is a patient specific study, hence the femur bone model is generated using patient Computed Tomography (CT) scans. The bone model was assigned a heterogeneous isotropic material property derived from patient CT data. The finite element (FE) model of the bone was meshed using Hypermesh. The peak loading condition including the muscle forces were applied on the native bone model along with the Recon and the Antegrademodel. While the loading conditions during normal walking cycle were only applied to theRecon and the Antegrade model to compare the impacts of the two implant types. Both loading conditions were simulated by fixing the distal condyle region of the bone. The analysis results show that the Antegrade implant experiences much higher stresses and strains in the neck region as compared to Recon implant. Also, the presence of the intermedullary nail through the femur diaphysis helps to distribute the stresses and strains in the anterior distal diaphysis region of the bone. For the case of no implants, the model showed strains and stresses in the lateral distal region of femoral diaphysis.

Femoral neck fracture (FNF) is a great challenge for today´s health care and is associated with high mortality and morbidity in the elderly.  In the short term several studies in the literature have demonstrated improved hip function, quality of life and fewer re-operations in elderly patients treated with total hip arthroplasty (THA) instead of internal fixation (IF). There are few reports on the long-term outcome comparing IF and THA. The vast majority of orthopaedic departments in Sweden use the direct lateral (DL) or posteriolateral (PL) approaches for hip arthroplasty. The PL approach has been linked to an increased risk of dislocation of the prosthesis and a higher rate of revision surgery in comparison to the DL approach. There are few reports focusing on radiological risk factors for prosthetic dislocation and patient reported hip function comparing the two surgical approaches for hip arthroplasty in FNF. The randomized controlled trial (RCT) is the gold standard for evaluating medical or surgical interventions. An RCT of high quality has to be internally and externally valid. Internal validity refers to a correct study design to avoid bias skewing the results. External validity (EV) refers to whether the results will be clinically relevant to a definable group of patients and can be extrapolated to the general health care situation. There are only a few reports in the orthopaedic literature focusing on the EV of published studies and none in the field of hip fractures. Study I: This is a RCT of 100 patients with a displaced FNF comparing THA and IF. Follow-up evaluations were performed at three months and 1, 2, 4, 11 and 17 years. It was found that the Harris hip score (HHS) was higher and the rate of reoperations lower for patients treated with THA. Study II: This is a prospective cohort study of 185 hips, comparing the DL and the PL approaches in patients treated with a hemiarthroplasty (HA) for a displaced FNF. Follow-up was after 1 year. There was no difference in patient reported outcome between the groups measured with the HHS and WOMAC index. The PL approach resulted in a higher re-operation rate while the DL approach in a higher incidence of limping. Study III: This is a retrospective cohort study of 373 patients with a cemented bipolar HA using a PL approach for a FNF with a follow-up ranging from 6 months to 7 years. Radiographs and all surgical records were reviewed regarding femoral offset (FO), leg length discrepancy (LLD) and Wiberg angle. Patients with recurrent dislocations had a decreased postoperative FO, LLD and shallower acetabulum on the operated side compared with their controls. Study IV: This is a prospective cohort study of 840 hips comparing patients included in a RCT with those that did not give their informed consent (NC) or did not fulfill the criteria for participating in the trial (MS). Patients in the NC and MS groups had an increased mortality rate in comparison to those included in the study. We did not find any differences in hip function between these groups. The main conclusions of this thesis are: Healthy and lucid elderly patients with good hip function preoperatively, should be treated with THA for a displaced FNF. The DL approach is favourable in treating displaced FNF with HA due to its decreased risk of reoperation but with an identical hip function outcome as the PL approach. Care should be taken to restore the LLD and FO otherwise this may increase the risk of recurrent dislocation of a HA. Our findings suggest that trial participants had a lower mortality rate than non-participants but the functional outcome of non-participants appeared to be satisfactory. This is important to take into consideration when extrapolating study results to a health care system.
Lårbenshalsfrakturer (FNF) är en utmaning för dagens sjukvård och förknippad med hög mortalitet i den äldre befolkningen. FNF orsakas främst av lågenergitrauma efter fall i samma plan hos patienter med benskörhet. Total höftledsprotes (THA) har visat sig ge en bättre höftfunktion, livskvalitet med färre omoperationer hos äldre patienter än sluten reposition samt fixering med skruvar (IF) under de första två-fyra åren efter operation. Få studier har publicerats med långtidsuppföljning av THA jämfört med IF. Vid behandling av felställd FNF med halv höftledsplastik (HA) eller THA finns olika kirurgiska metoder (snittföring) för implantation av protesen. Majoriteten av ortopedkliniker i Sverige använder direkt lateral (DL) eller posteriolateral (PL) snittföring. PL har kopplats till en ökad risk för luxation av protesen (urledsvridning), vilket i sin tur genererat en högre risk för omoperation jämfört med DL. Få studier har utvärderat höftfunktion med avseende på snittföring. Detsamma gäller vilka radiologiska faktorer som påverkar risken förprotesluxation. Det finns olika typer av studiedesigner för utvärdering av medicinska och kirurgiska behandlingsmetoder. Studiedesignen med högst bevisvärde anses vara den randomiserade kontrollerade studien (RCT). För att en RCT skall hålla hög kvalitet krävs intern och extern validitet. Intern validitet syftar på ett korrekt studieupplägg som mäter det som avses och undviker påverkan av icke önskvärda faktorer. Extern validitet (EV) innebär att erhållna resultat från studien är generaliserbara och kan extrapoleras till andra grupper än den studerade. Det inga rapporter i ortopediska litteraturen med fokus på EV med patienter som drabbats av FNF. Studie I: Prospektiv randomiserad studie av 100 patienter med en felställd FNF jämförs THA med IF med avseende på höftfunktion och reoperationer. Uppföljning gjordes efter tre månader samt 1, 2, 4, 11 och 17 år. HHS som mått på höftfunktion var högre och andelen reoperationer lägre för patienter som behandlades med THA. Studie II: Prospektiv kohortstudie med 183 patienter med felställd FNF behandlade med HA och antingen DL eller PL. Vi fann ingen skillnad i patientrapporterad höftfunktion utvärderat med HHS och WOMAC efter 1 år men en ökad förekomst av hälta vid DL. Studie III: Retrospektiv kohortstudie av 373 patienter opererade med en cementerad bipolär HA och PL. Postoperativa röntgenbilder granskades avseende femoral offset (FO), postoperativ benlägdsskillnad (LLD) samt acetabulär Wibergvinkel och relaterades till återkommande protesluxationer. Detta relaterades till återkommande luxationer. Uppföljningstiden varierade mellan 6 månader och 7 år. Patienter med återkommande luxationer hade en minskad postoperativ global FO, förkortad LLD och grundare acetabulum på den opererade sidan jämfört med kontroller. Studie IV: Prospektiv kohortstudie av 840 patienter med felställd FNF där patienter som ingick i en RCT jämförs med de som inte gav sitt samtycke för deltagande eller ej inkluderats i screeningprocessen. De patienterna som inte gav sitt samtycke hade ökad dödlighet, men ingen skillnad i höftfunktion jämfört med deltagare. Slutsatser • Friska och kognitivt vitala äldre patienter med god höftfunktion innan en felställd lårbenshalsfraktur bör behandlas med total höftledsprotes. • DLsnittföring ger ett lika bra patientrapporterad höftfunktion men en ökad förekomst av hälta jämfört med PL snitt vid behandling med halvprotes på grund av en felställd lårbenshalsfraktur. • Ansträngning bör göras för att återställa benlängdsskillnad samtfemoral offset och därigenom minska risken för återkommande luxation. • Våra resultat tyder på att patienter som deltar i en randomiserad studie har lägre dödlighet än patienter som avböjt att delta samt de som missats i screeningprocessen. Det är viktigt att ta hänsyn till när extrapolerar studieresultat till ett hälso-och sjukvårdssystem. Detta bör vägas in i värderingen av studieresultatens externa validitet.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
O objetivo do estudo foi verificar os efeitos do carbonato de lodenafil no processo de consolidaÃÃo Ãssea nos fÃmures de ratos reduzidos com fio de Kirshner. Os fatores vasculares sÃo extremamente importantes para a formaÃÃo do calo Ãsseo. O carbonato de lodenafil causa efeitos vasodilatadores, pertence ao grupo dos inibidores da fosfodiesterase seletiva para o tipo 5 (PDE5), enzima que hidrolisa monofosfato de guanosina cÃclico (GMPc). O GMPc induz o relaxamento da musculatura lisa, sendo utilizado no tratamento da disfunÃÃo erÃtil. Foram utilizados 36 ratos machos, adultos, da linhagem Wistar, com o peso mÃdio de 300g. Todos os animais foram submetidos a cirurgia em que era realizada a fratura da diÃfise femoral com uma guilhotina romba. Os animais foram divididos em 2 grupos: o grupo lodenafil, que recebeu, via oral, doses diÃrias de carbonato de lodenafil (10mg/kg) e o grupo controle. Os animais foram sacrificados com 7, 14 e 28 dias de pÃs-operatÃrio. Houve duas mortes, dois falsos trajetos do fio e em trÃs animais nÃo foi estabelecida a fratura. Foram realizados estudo radiogrÃfico com filme de mamÃgrafo para analisar a densidade Ãptica e Ãrea do calo Ãsseo, medida em mm e estudo histolÃgico, utilizando amostras coradas com picrosirius red sob a luz poralizada do microscÃpio, para quantificar a formaÃÃo de colÃgeno tipo I e tipo III na regiÃo cortical prÃxima a fratura e no calo Ãsseo. A densidade de colÃgeno tipo I na regiÃo cortical do fÃmur prÃximo à fratura verificada no grupo lodenafil foi significantemente menor que a observada no grupo controle com 28 dias de consolidaÃÃo Ãssea (**P = 0,0028). Os resultados encontrados nÃo sÃo consistentes o suficiente para afirmar que este fÃrmaco exerce algum efeito na consolidaÃÃo Ãssea. Verificou-se que o Carbonato de lodenafil nÃo influenciou no processo de consolidaÃÃo Ãssea nos fÃmures de ratos reduzidos com fio de Kirshner.
The study was to investigate the effects of Lodenafil Carbonate in the process of bone healing in femurs of rats with reduced KirshnerÂs wire. The vascular factors are extremely important for the formation of callus. Lodenafil Carbonate cause vasodilatory effects, belongs to the group of selective phosphodiesterase type 5(PDE5) inhibitors, that enzyme inhibits cyclic guanosine monophosphate (GMPc) and relaxation of smooth muscles and are used to treat erectile dysfunction. It used 36 male rats, adult male rats, with the average weight of 300g. All animals underwent surgery in which fractures to the femoral shaft with a blunt guillotine. The animals were divided into 2 groups: lodenafil group, wich received oral doses of carbonate lodenafil (10mg/kg) and the control group. The animals were sacrificed at 7, 14 and 28 days postoperatively. There were two deaths, two false paths of the wire and three animals was not established fracture. Were performed radiographic studies with film mammography to analyze the optical density and area of callus, measured in mm  and histological study, using samples stained with picrosirius red under microscope light polarization, to quantify formation of collagen type I and type III in the cortical region near the fracture and callus. The density of type I collagen in the cortical region of the femur near the fracture observed in group lodenafil was significantly lower than that observed in the control group at 28 days of bone (** P = 0.0028). The results are not consistent enough to say that this drug has an effect on bone healing. It was found that the carbonate lodenafil not influence the process of bone healing in femurs of rats with reduced wire Kirshner.

The mevalonate pathway is an important biosynthetic pathway, found in all cells of virtually all known pro- as well as eukaryotic organisms. This thesis is an investigation into the use of two drugs, originally developed for different applications, but both affecting the mevalonate pathway, in to models of fracture repair. Using two different rodent models of fracture repair, a commonly used cholesterol lowering drug (statin) and two drugs used to treat osteoporosis (bisphosphonate) were applied both systemically as well as locally in order to enhance fracture repair. Papers I and II investigate the potential of simvastatin to improve the healing of femoral fractures in mice. Papers III and IV explore the use of two bisphosphonates to improve early fixation of stainless steel screws into rat bone. The statin simvastatin lead to an increased strength of the healing cellus. The application of bisphosphonates increased early screw fixation. It seems clear that both drugs have uses in orthopaedic applications. One interesting avenue of further research would be to combine the two classes of drugs and see if we can get the benefits while at the same time diminishing the drawbacks.

The overall aim of this thesis was to evaluate the outcome when treating children for displaced femoral fractures with external fixation.

In a consecutive and prospective study during the period 1993-2000, 96 children aged 3-15 years with 98 displaced femoral fractures were treated with external fixation and early mobilisation. The mean age was 8.1 years, the mean hospital stay was 8.7 days and the mean treatment time was 61 days. All fractures healed. Minor complications included pin tract infections (18%), clinical insignificant malunions, heterotopic ossification and two re-reductions. Major complications (6%) included two re-fractures after significant trauma and three plastic deformations after premature fixator removal leading to an osteotomy.

Radiological evaluation was performed up to one year for the whole group and for a subgroup up to two years. The evaluation showed that malunions were few and prone to remodelling almost completely. Although the fractures were fixated without shortening, as recommended earlier, the overgrowth was far less than expected.

Isokinetic muscle strength was measured in both hamstrings and quadriceps in 31 of the patients and compared with 31 matched children without previous injury to the legs. Early mobilisation seems to prevent residual muscle weakness previously shown after treatment with traction or cast for femoral fractures in children.

A cost analysis was performed, comparing three different treatment modalities of femoral shaft fractures: traction in hospital, traction in hospital/at home and external fixation. The analysis included both total medical costs and costs for the care provider. The most important factors were days spent at the hospital and the sick leave for the care provider. Treatment that can minimise these factors will contribute strongly to a lowering of health care costs.

Conclusion: External fixation of displaced femoral fractures in children can be used as standard treatment in children aged 3-15 years. The treatment provides satisfactory results with a low rate of major complications. Early mobilisation seems to prevent residual muscle weakness. The treatment reduce the number of days in hospital and the number of days of sick leave for the care provider and contributes strongly to lowering health care costs.

Orientador: William Dias Belangero
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: INTRODUÇÃO: O tratamento cirúrgico das fraturas intertrocanterianas do fêmur ainda é motivo de estudo e controvérsias. As vantagens da utilização de técnicas minimamente invasivas para essas fraturas já despontam na literatura. O objetivo deste estudo foi avaliar as complicações da técnica minimamente invasiva que utiliza um implante e um instrumental desenvolvidos especificamente (Sistema Minus) para o tratamento dessas fraturas. CASUÍSTICA E MÉTODO: Foram estudados 172 pacientes com fratura intertrocanteriana do fêmur, tratados com o Sistema Minus, dos quais 52 pacientes foram excluídos do estudo por não terem preenchido os critérios de inclusão. No protocolo inicial foram registrados o gênero, a idade, detalhes operatórios como tempo cirúrgico, tempo de uso da fluoroscopia, qualidade da redução e da fixação da fratura. Como parâmetros clínicos foram incluídos a capacidade de marcha, dor, classificação da fratura segundo os critérios de Tronzo e o risco anestésico segundo a classificação de ASA. Dividimos as complicações em dois grupos. As complicações gerais, subdivididas em infecção e mortalidade e as complicações específicas, subdivididas em migração do implante, a perda da redução e a falta de união. Embora a migração do pino deslizante não seja considerada na literatura como uma complicação do DHS (Hrubna e Skotak, 2010)1, no presente estudo ela foi incluída. Cabendo salientar que foi considerada como migração, a impacção lateral da fratura sem a ocorrência de perda de redução. RESULTADOS: O gênero feminino ocorreu em 93 casos e obteve percentual de 77,5%, foi prevalente em relação ao masculino com 27 casos e 22,5%. A idade variou de 52 a 95 anos, com a média de 80,06 anos e desvio padrão de 7,87 anos. A média de idade do gênero masculino foi de 76,19 anos e desvio padrão de 8,321. O gênero feminino obteve a média de 81,18 anos com desvio padrão de 7,407. O tempo cirúrgico médio foi de 39,35 minutos, variando de 25 a 65 minutos. O tempo médio de radioscopia foi 1min7s, variando de 0,6 a 2 minutos e 3s. A redução foi considerada adequada em 92 casos (76,6%), quando obteve-se o alinhamento do eixo de carga, como valgo em 20 casos (16,6%) e como varo em oito casos (6,6%). O somatório médio do TAD (Tip Apex Distance) na incidência Ântero-posterior (AP) foi de 1,19cm, variando de 0,2 a 2,8cm; e no Perfil (P), de 1,14cm, variando de 0,3 a 2,52cm. Dos pacientes, 112 (93,3%) voltaram a andar e a dor pós-operatória em uma escala de 0 a 10, teve a média de 4,44. Dos 120 pacientes, 11 foram classificados como Tronzo I (9,1%), 24 como Tronzo II (20%), 58 como Tronzo III (48,3%), sete Tronzo III variante (5,8%) e 20 Tronzo IV (16,7%). As fraturas instáveis ocorreram em 85 (70,8%) pacientes, os quais 74 (61,6%) tinham idade superior a 75 anos. Já as fraturas estáveis em 35 (29,1%) pacientes, os quais 17 (14,1%) possuíam idade superior a 75 anos. Em relação ao risco anestésico, oito (6,6%) foram classificados como ASA I, 33 (27,5%) ASA II, 74 (61,6%) ASA III e cinco ASA IV (4,16%). Houve um caso de infecção (0,83%). Ocorreram 13 óbitos (10,8%) dentro do primeiro ano de pós-operatório. Desses, um (0,83%) foi classificado como Asa II, cinco (4,16%) como Asa III e sete (5,83%) Asa IV. Dos 85 pacientes com fraturas instáveis, 36 (30%) apresentaram complicações, como perda de redução em 7(5,88%) e migração do pino deslizante em 29 (24,1%). No grupo das 35 fraturas estáveis, as complicações ocorreram em 4 casos (3,33 %), sendo que a perda de redução ocorreu em um caso (0,83%) e a migração em 3 casos (2,5%). No total, a migração ocorreu em 33 casos (27,6%), sendo que desses, todos evoluíram para consolidação. A perda de redução ocorreu em oito (6,7%) e a falta de união, em um caso (0,83%). CONCLUSÃO: Concluímos que a técnica minimamente invasiva, Sistema Minus, é uma técnica segura, que permite a realização da cirurgia com baixa incidência de complicações, quando comparada aos demais métodos existentes
Abstract: INTRODUCTION: The surgical treatment of intertrochanteric fractures is still controversial, resulting in further studies. Many papers have appeared in reference to the advantages of minimal invasive procedures for these fractures. The aim of this study was to evaluate the complications of a minimal invasive procedure using a specific implant and instruments developed for the treatment of intertrochanteric fractures (Minus System). MATERIAL AND METHOD: One hundred and seventy two patients with intertrochanteric fractures of the femur were studied, and submitted to treatment with the Minus System. Fifty two patients were excluded from the study as they did not fulfil all criteria for inclusion. The initial protocol registered gender, age, operative details such as length of operation, length of fluoroscopy use, quality of reduction and fixation of the fracture. The clinical parameters considered included deambulatory ability, pain, Tronzo fracture classification and anesthesia risk according to ASA classification. Complications were divided into two groups: general complications (infection and mortality rate) and specific complications (implant migration, loss of reduction and non-union). Although the migration of a sliding nail has not been considered in the literature as a DHS complication (Hrubna e Skotak, 2010)1 RESULTS: There were 93 feminine cases (77.5%) prevailing on 27 masculine cases (22.5%). Age span was 52 to 95 years, with an average of 80.06 years (standard deviation of 7.87 years). The average age for men was 76.19 years with a standard deviation of 8.321. The average age for women was 81.18 years with a standard deviation of 7.407. The average operative length of time was 39.35 minutes (25 to 65 minutes). The average time of fluoroscopy was 1min 7sec (0.6 to 2min 3sec). Fracture reduction was considered adequate in 92 cases (76.6%), , in the present study it was taken into account. It is important to mention that migration here is the lateral impaction of the fracture without loss of reduction. when alignment with weight-bearing axis was obtained, valgus in 20 cases (16.6%) and varus in eight cases (6.6%). The average Tip Apex Distance (TAD) on an anteroposterior view was 1.19cm (variation of 0.2 to 2.52 cm) and lateral view was 1.14cm (variaton of 0.3 to 2.52cm). One hundred and twelve patients (93,3%) were able to walk with postoperative pain (average of 4.4 on a pain scale of 0 to 10). The classification of the 120 patients is as follows: 11 patients with Tronzo I (9,1%), 24 cases of Tronzo II (20%), 58 Tronzo III (48.3%), seven Tronzo III variant (5.8%) and 20 Tronzo IV (16.7%). Unstable fractures occured in 85 (70.8%) patients, and 74 (61.6%) were over 75 years of age. There were 35 stable fractures (29.1%), with 17 patients (14.1%) over 75 years of age. As to the anesthesia risk eight (6.6%) were classified as ASA I, 33 (27.5%) ASA II, 74 (61.6%) ASA III and five patients as ASA IV (4.16%). There was one case of infection (0.83%). During the first postoperative year there were 13 deaths (10.8%). Of these, one patient (0.83%) had been classified as ASA II, five (4.16%) as ASA III and seven (5.83%) as ASA IV. There were 36 patients (30%) with complications out of 85 patients with unstable fractures, with loss of reduction in seven (5.88%) and migration of the sliding nail in 29 (24.1%). In the group of 35 stable fractures there were complications in four cases (3.3 %), with loss of reduction in one case (0.83%) and migration in three (2.5%). The total number of migrations was 33 (27.5%), but resulted in union in all patients. The loss in reduction occurred in eight patients (6.7%) and non-union in one case (0.83%). CONCLUSION: The minimal invasive procedure, the Minus System, is a safe procedure, that provides adequate surgery with a low incidence of complications, when compared to other existing techniques
Doutorado
Fisiopatologia Cirúrgica
Doutor em Ciências

Bei der internen, extramedullären Osteosynthese des distalen Femurs, auf die sich diese Arbeit fokussiert, haben sich in den letzten Jahren interessante Entwicklungen vollzogen. Ausgehend von unzufriedenstellenden Komplikationsraten wurden neue Wege in der Versorgung dieser schwierigen Frakturen gesucht. Osteosynthesematerialien, Repositionstechniken, die Technik der Implantatplatzierung und die Implantate selbst, bei denen die Entwicklung zu winkelstabilen Systemen gegangen ist, haben sich grundlegend geändert. Die vorliegende Arbeit analysiert in einer retrospektiven Studie distale Femurfrakturen, die zwischen dem 1.1.1995 und 31.9.2000 entweder mit einem Fixateur interne (LISS) oder mit der konventionellen Plattenosteosynthese versorgt wurden. In die Studie konnten 51 Patienten mit 54 distalen Femurfrakturen eingeschlossen werden. Die Infektionsrate war in der LISS-Gruppe (0% versus 11,1%) nichtsignifikant geringer, die Rate der verzögerten Frakturheilungen war nichtsignifikant höher. Die einzige verzögerte Frakturheilung (LISS-Gruppe), die einer sekundären chirurgischen Intervention bedurfte, wurde bei einer Patientin mit einem großen Knochendefekt gesehen, der ohne primäre Spongiosaplastik therapiert worden war. Pseudarthrosen traten in beiden Gruppen nicht auf. Die Rate des Materialversagens unterschied sich nicht signifikant. Beim LISS kam es nicht, wie bei den konventionellen Implantaten zu sekundären Repositionsverlusten, es wurden aber im Anfang der klinischen Einführung proximale Schraubenausrisse aufgrund einer Fehlplatzierung gesehen. Es konnte gezeigt werden, dass es durch die Verwendung des LISS und die indirekten Repositionstechniken zu keiner Zunahme der Achsfehlstellungen oder der Operationszeit kam. Die funktionellen Einzelergebnisse und die Punktzahl der erhobenen Scores (Neer-Score und Lysholm-Score) unterschieden sich nicht signifikant.
Internal, extramedullary osteosynthesis of distal femoral fractures which are focussed on in this study has been influenced by interesting developments in recent years. Driven by unsatisfying complication rates new fracture treatments have been looked for. Osteosynthesis materials, reduction techniques, techniques of implant placement and implants themselves - where development went to angular stable systems - have changed decisively. This study analyzes in a retrospective setting distal femoral fractures which were treated between 1.1.1995 and 31.9.2000 either with an internal fixator (LISS) or with conventional plate osteosynthesis. In this study 51 patients with 54 distal femoral fractures could be included. The Infection rate was non significantly lower in the LISS group (0% versus 11,1%), the rate of delayed union was non significantly higher. The only delayed union in the LISS group which needed secondary surgical intervention was seen in a patient with considerate bone loss which was not treated by primary bone grafting. Non-unions were not seen in either group. The rate of implant failure did not differ significantly. In the LISS group no secondary loss of reduction (like in the group with conventional plate osteosyntesis) was seen but proximal screw pull out due to malplacement was reported in the beginning of clinical introduction. It could be demonstrated the LISS and indirect reduction leading not to a higher rate of malalignement nor to prolonged theatre times. Functional results and the point score of the Neer Score and the Lysholm Score showed no significant difference.

碩士
長庚大學
醫療機電工程研究所
105
Background: The treatment of periprosthetic femoral comminuted fracture following total hip arthroplasty remains challenge for Orthopedist. Secondary bone healing is considered the main mechanism for comminuted bone fracture, whereas an appropriate interfragmentary motion (IFM) at the fracture site is required to achieve secondary bone healing. Currently, the combination of locking plate (bridge fixation) with bi-cortex fixation is regarded as the golden standard for treatment of periprosthetic femoral comminuted fracture. This technique, however, provides a rigid plate/screw connection, which limit motion at the fracture gap near the plate. Contrarily, excess IFM can occur in the fracture gap at the far cortex, suppressing secondary bone healing. Consequently, a new trend of a combination of locking plate and far-cortex fixation gains attention in treating periprosthetic femoral comminuted fracture. This technique makes a more consistent IFM (increase IFM at near-cortex, whereas decrease IFM at far-cortex), leading to the beneficial for promotion of secondary bone healing. However, until now, literatures exploring the biomechanical behavior of such surgical technique are lacking. This study is thus aimed to investigate the biomechanical performance of femoral constructs following treatment of periprosthetic femoral comminuted fracture using locking plate. The following combinations of parameters are analyzed: three types of stems (VerSys®, Fiber Metal MidCoat, CLS Spotorno; Zimmer), three positions of fracture sites (stem tip, 10 mm proximal to stem tip (proximal-10mm), 10 mm distal to stem tip (Distal-10mm)), and two screw fixation techniques (far-cortex and bi-cortex fixation). Methods: A total of 18 finite element models (combinations of 3 stems, 3 fracture sites and 2 screw-fixation methods) were created using computed tomography images of human femur. A 10-mm fracture gap was created to simulate comminuted fracture. The boundary condition was assumed by 750N body weight with single leg stance. The effects of the aforementioned parameters on stress and displacement distribution of femur, plate, screw, and together with IFM were examined, respectively. Result: 1). Regardless of stem types and fixation techniques, femoral construct with fracture site of proximal-10mm presented the highest stress distributions compared to those of femora with fracture sites of stem tip and distal-10mm. 2). Regardless of stem types and fracture sites, far-cortex fixation obviously increased the stress of fixation screw. 3). Regardless of stem types, far-cortex fixation increased IFM (reduction of stiffness) at near-cortex and decreased IFM (increase of stiffness) at far-cortex for fracture sites of stem tip and distal-10mm (without stem support); whereas no obvious IFM change was found between far-cortex and bi-cortex fixation for fracture site of proximal-10mm (with stem support). 4). Regardless of fixation techniques, the displacement of femoral head increased with increasing stem length for fracture sites of stem tip and distal-10mm. Conclusion: As compared to traditional bi-cortex fixation, periprosthetic femoral comminuted fracture treated with far-cortex fixation might makes a more consistent IFM, leading to the beneficial for promotion of secondary bone healing.

碩士
國立臺灣科技大學
應用科技研究所
107
Femoral fracture is one of the most common fractures in human body. Locking compression plates have been widely used for the treatment of femoral fractures. Different strategies for femoral fractures have been developed to enhance the mechanical stability of locking plate fixation. Previous studies have found that the number and the position of the screw were the key factors in the stability of the locking plate. However, most studies used a simplified femoral numerical model which cannot truly evaluate the biomechanical results of implant to investigate the influence of screws number and position. In the present study, we developed a finite element (FE) model of lower limb to investigate the biomechanical performance of the various locking plate fixation strategies in femoral fractures during the gait. A complete lower extremity model in present study included pelvis, femur, tibia and foot. The complete lower limb models, screws and locking plates were created by Solidworks, and then imported into ANSYS 19.2 Workbench. Three periods of the gait cycle were considered including Foot flat, Mid-stance and Heel off phases. In terms of the fixation strategy, the screws were divided into seven types of screws numbers and screw positions. The FE analysis was performed to investigate the influence of the number and position of the screws in three different postures. The results were presented by evaluating the fracture displacement and the maximum stress of locking plate and screw. Among the FE models in three postures, the results showed that the foot-to-ground model had higher maximum stress of both locking plates and screws, which improved the failure of implants. As the plate working length increased, the maximum stress of both locking plates and screws decreased. The results suggest that applying ten screws could have a better fixation performance. This study could provide useful information for the treatment of distal femoral fracture.

碩士
國立中山大學
企業管理學系醫務管理碩士班
106
Objective: This study focuses on the analysis of medical care in elderly patients with femoral neck fracture during the intervention of internal fixation surgery, comparing medical resources utilization of different hospitalized days. Method: This research adopted a retrospective cohort study. The samples were identified using National Health Insurance Research Database in Taiwan, chosen by the group of femoral neck fractureinpatients with internal fixation surgery according to ICD-9-CM diagnostic code. The research samples were classified into two groups, including the performing internal fixation surgery within two inpatient days (case group) and above three inpatient days (control group) respectively. Every sample was tracked three years from the first day of surgery. The research was discussed and analyzed by medical utilization, bad prognosis and infection proportion. We used descriptive statistics to analyze the differences of medical care and resource utilization between two groups, such as chi-square, t-test and cox proportional regression. Results: The result of cox proportional regression model analysis in this study showed that the case group (hospitalized above three days) had the significantly higher risk of ill prognosis and infection than the control group (hospitalized within two days), and the hazard ratio were 1.22 and 1.69 respectively. Besides, the results showed that in the case group the number of outpatients was 8.07(SD=18.6), the average length of hospital stay was 11.33 days (SD=8.48), and the average medical cost of hospitalization was NT$ 5,839(SD=14,822.50). Analyzed by t-test, the number of outpatients, average length of hospital stay and average medical cost of hospitalization were all significantly higher in the case group than in the control group(p<0.05). Conclusion: The research demonstrated that a patient hospitalized above three days had significantly higher risk of ill prognosis and infection than hospitalized within two days after treatment of internal fixation surgery. The research also showed that case group utilized more medical resource than control group. Thus, to promote the health of femoral neck fracture patients and achieve the purpose of reducing wasted medical resource, we should give the treatment of internal fixation surgery to hospitalized patients suffering from femoral neck fracture as soon as possible.

碩士
國立臺灣科技大學
機械工程系
99
Locked compression plates (LCP) have been widely used for a diaphyseal femoral fracture treatment and showed an improved fixation in osteoporotic bone. The clinical experiences have been used to investigate the fixation stability of the bone by considering several numbers and positions of the screws in the twelve-hole LCP. In fact, there are a lot of possible locations which can be placed in the plate holes. As an example, for six screws in the twelve-hole plate, there would be 924 possible locations of the screws. The purpose of this study is to discover the best screw configurations in the twelve-hole bone plate within two finite element (FE) models. A novel biomechanical optimization method namely Finite Element Analysis (FEA)-based Discrete Particle Swarm Optimization (DPSO) was used to find the optimum design. The results showed that increasing the number of screws decreased the motion of the constructs, and the performance of three screws per main segment shows no about significant different, compared to all screws occupied the plate hole, this lead to a conclusions that the stability can be achieved by increasing the number of screws and three screws on either of the fracture provide sufficient stability while minimizing the complications of plate fixation. Moreover, this method is flexible and can be applied to various FE models with certain defined boundary and loading conditions.

碩士
中臺科技大學
醫療暨健康產業管理系碩士班
102
Introduction: Proximal femoral fractures, including femoral neck fractures, intertrochanteric fractures and subtrochanteric fractures, often occur in people aged 60 or older and will cause patient’s immobility, severe pain and affect their quality of life. This study aims to compare the failure rates within two years that pateints with proximal femoral fracture treat with metal internal fixation or artificial hip arthroplasty in people aged more than 60 years or older in Taiwan. Materials and Methods: This study was a secondary analysis of data that used the database, from 2004 to 2008 National Health Insurance database of academic research hospital data in National Health Research Institutes, for analysis. In the study, we selected the patients, more than 60 years of older, with proximal femoral fractures for study. The methods of statistics used descriptive statistical with SPSS17.0, t-test and logistic regression analysis. Results: The number of people with femoral neck fractures, intertrochanteric fractures, subtrochanteric fractures and proximal femoral fractures for hospitalization were 40051, 35130, 2767 and 77948 people between 2004-2008. These patients treated with metal internal fixation and failure rates were 10.6%, 5.9%, 12.0% and 7.2%. Patients treated with hip arthroplasty with lower surgical failure rates, 4.0%, 5.2%, 2.0% and 4.1%. In different levels of care of medical institutions, the highest surgical failure rate is regional hospitals. The highest surgical failure rates of top three division of National Health Insurance Administration were respectively Taipei division, Central division and Southern division. Conclusion: There are 5 main risk factors affecting surgical failure for proximal femoral fractures: age, gender, fracture sites, types of surgery and level of care of the hospital. There are about 2.7% reductions in the risks of surgical failure for every increment of one year of the patient’s age. The surgical failure rates were lower in men than women, about 0.88 times that of women’s. The surgical failure rates of extracapsular femoral fractures were lower than femoral neck fractures, about 0.76 times. The surgical failure rates for patient who received metal internal fixation were higher than patient received hip arthroplasty, about 2.4 times. There were different surgical failure rates in hospitals with different levels of care. Compared to medical centers, the surgical failure rates were higher in regional hospitals, up to 1.03 times, and in local hospitals, about 1.15 times.

碩士
國立臺北科技大學
機電科技研究所
103
Femoral neck fracture is one of the common orthopedic injuries, However, optimal fixation of the vertical fractures with a higher Pauwels’ angle (Pauwels III) remained an unsolved problem despite extensive biomechanical and clinical research available. Based on the past literature, this study was to design a simplified femur fixture means to replace cadaver and femur sawbone specimens. It not only could save the time of preparing specimen but also could change the density parameter of sawbone specimens. However, according to the past literature, there was not too much research focusing on comparing the biomechanical analysis of simplified femur fixture and femur sawbone. Therefore, the objective of this study was to use biomechanical testing and finite element analysis to investigate the stability and biomechanical efficiency of the femoral neck with a higher Pauwels’ angle after fixation with three parallel cancellous lag screws, as well as the dynamic hip screw system. Moreover, four different configurations (A. triangle, B. inverted triangle, C. vertical-1: two superior and one inferior, D.vertical-2: one superior and two inferior) were considered for the cancellous lag screw fixation and two bone mineral density (A. normal, B. osteoporosis ) to evaluate the biomechanical efficiency for the femoral neck fracture fixation. Finite element analysis results showed that there was a highly match between the simplified femur fixture and femur sawbone model (Max Von Mises stress is displayed in the same cancellous screw (error 0.77%)), so the simplified femur fixture would be used on the biomechanical testing in this study. Biomechanical test results showed that two superior and one inferior vertical configurations of the cancellous screw had greater compression stiffness (804.24 ± 79.58 N / mm) and failure load (2.408 ± 0.359 kN) in normal bone mineral density. In addition, DHS had greater failure load (1.359 ± 0.435 kN) in osteoporosis bone mineral density. Moreover, DHS in the failure energy of these two bone mineral density (12.54 ± 4.67 J, 6.32 ± 0.87 J) are significantly better than the implanted cancellous screw. The results of this project aimed to evaluate the biomechanical efficiency of different internal fixation devices for the treatment of Pauwels type III femoral neck fractures. When the Bone mineral density was well, femur which was implanted with two superior and one inferior vertical configurations of cancellous screw had a greater and better resistance to mechanical effects of hip load. Those who suffered from osteoporosis could have the operation of dynamic hip screw, and this could provide better biomechanical effects. Furthermore, the quantified data will also be used as reference for implant design and surgical procedure improvement.

碩士
國立陽明大學
醫學工程研究所
88
The management of ipsilateral distal femoral (supracondylar) fracture after total knee arthroplasty (TKA) is still a controversial to the orthopaedic surgeon. Although there were some fixators for the stabilization of supracondylar femoral fracture and biomechanical test were investigated, there were few studies made with the fractures after TKA. This study had tried to design a new internal fixator for the fracture of distal femur after TKR. The biomechanical test was conducted to compare the mechanical properties (axial and torsional stiffness) of the femur which were restabilized by different fixators(DCP, GSH and new design). The new fixator was designed with an intramedullary nail to be fixed on the femoral component of the total knee prosthesis. So there is no movement between the two pieces of the implants. Therefore, this new internal fixator could have greater structure stiffness by increasing the structure contact area. To test this improvement, the femoral component was implanted on the artificial composite bone (composite bone, SAWBONESR, USA) and made a mimic supracondylar femoral fracture(transverse pattern). The fractures were fixed with new designed fixator or traditional DCP plate or GSH nail(five samples in each group). The axial compression test and torsional test were done by the MTS Bionix858 to compare the mechanical stability of these fixators with intact bone(no fracture) and prosthesis implanted bone(no fracture). There is no significant difference between each group in axial stiffness, which means that these three fixators can stabilize the fracture effectively in the longitudinal direction. All three fixation groups (Nail, Plate, New) are lower than the no fracture group (Intact, Prosthesis) with significant difference. But the torsional stiffness of the new designed foxator is higher than the DCP plate and GSH nail.

碩士
國立臺灣科技大學
機械工程系
101
An interlocking nail system has become a standard treatment for femoral shaft fracture, because of the superiority of better stability over plates. The usual fixation of traditional nail is static fixation for its great stability, however, a traditional nail with static fixation may make femoral fracture nonunion owing to the gaps between fracture fragments. Then, immediate dynamization is regarded as an effective treatment for nonunion. The principle of dynamization with traditional nail is to remove all proximal or distal screws to reduce gaps within fracture fragments and facilitate bone union, but it may decrease rotational stability due to one end fragment without any screw fixation. Thus, consider another effective dynamization with slotted nail, which can just remove one screw and make another screw preserved in the slot hole, not only keeping rotational stability but facilitating bone union. Unfortunately, the biomechanical performance of the interlocking nail systems with the slotted nail has not been investigated mechanically. Therefore, the purpose of this study was to investigate the biomechanical performance of the slotted nail in situation of the static or dynamic fixation techniques using finite element analysis. The commercial interlocking nails and the standardized femur model were used in this study. The biomechanical characteristics of traditional and slotted nail with static fixation technique and slotted nail with three kinds of dynamic fixation techniques applied to two types of femoral shaft fracture with antegrade and retrograde implanting were compared. To determine the biomechanical characteristics of different fixation techniques, the maximum von Mises stress of the implants；the axial stability and the rotational stability of whole femur were calculated. The results show that antegrade slotted nail at proximal fracture and retrograde slotted nail at distal fracture with removing one screw get minimum stress of the nail and maximum rotational stability. The dynamization technique with removing one screw gets smaller stress of nail and higher rotational reaction force than removing all screws at one end, that means removing one screw has much higher union rate. The result obtained in this study had the same outcome in clinical findings. The dynamization technique with removing one screw could reduce the stress of the nail and keep the rotational stability. The results of this study could help surgeons to realize the biomechanical characteristics of slotted nail and provide evidence to support the use of fixation techniques.

碩士
中原大學
電子工程研究所
96
Periprosthetic hip fractures are common complications in hip arthroplasty. Treatment of these special fractures is difficult because the canal is occupied by stem. Therefore traditional plate-screw system and intramedullary nail are not suitable. Several specially designed cable-plate systems are developed for the situation, but they are usually expensive and not ordinarily available. Wire-locked screw is developed by our team. 4.5 mm cortical screw is adapted and the screw head is elongated with holes, providing better fixation of circlage wire and avoiding wire slippage. In combination with 4.5mm DCP, unicortical purchase is achieved, and circlage wire is applied, providing better fixation of the fracture. In the study, three different fixation methods are investigated: 1.Doll-Miles cable plate system, 2.wire-locked screw and plate fixation, 3.Simple proximal wire fixation. By way of biomechanical testing, three loading condition including compression, bending, and rotation are tested. Then failure test is done by rotational moment. Stiffness of different fixators is compared. Results of biomechanical testing reveal that stiffness of wire-locked screw and plate fixation is better than another 2 fixation methods. Therefore, periprosthetic hip fractures can be handled properly by it.

碩士
國立成功大學
生物醫學工程學系
103
Proximal femoral periprosthetic fracture following THA is a gradually common problem occurring in recent years. Its difficulty and complexity of clinical treatment using plate and screw fixation draws many researchers’ attention. A new design, NCB-PP plate and screws, which were proposed with few discussed biomechanical property on cap-screw mechanism, was made clearer through our study. A biomechanical experiment and finite element analysis was conducted to show when the screw was fixed at zero degree, screw- cap construct has higher stiffness than that at 15 degree. Interestingly, screws fixed at 30 degree, over suggested design, has similar stiffness as zero degree. Further experiment and finite element analysis towards whole construct should be studied.