Yes / Cortico-steroid Injections (CSI) are commonly used to treat patients with Greater Trochanteric Pain Syndrome (GTPS) but it is unclear which patients will experience improvements in pain Objectives: To identify factors that influence improvements in pain for patients with GTPS treated with CSI Design: Systematic review Methods: A search was undertaken of AMED, CINAHL, Cochrane Library, EMBASE, Medline and PEDro databases. Studies were eligible for inclusion of they investigated factors that influenced changes in pain experienced by patients who received a CSI. Studies needed to include relevant summary statistics and tests of clinical significance. Risk Of Bias in Non-randomised Trials Of Interventions (ROBINS-I) and Risk of Bias 2 (ROB2) tools were used to assess bias. Results: The search identified 466 studies, 8 were included in the final review with a total of 643 participants. There was no association between demographic variables such as age, sex, symptom duration or obesity and pain outcomes post-CSI. Having a co-existing musculoskeletal (MSK) condition such as knee osteoarthritis or sacroiliac/lumbar spine pain was associated with less pain reduction post-CSI. Injections into the Trochanteric Bursa were associated with longer lasting pain reduction than Gluteus Medius Bursa or extra-bursal injections. Image guidance of CSI maintained lower pain scores at six months but did not increase the duration of the therapeutic effect past six months. The presence of specific ultrasound scan features was not associated with differences in pain scores. Conclusions: Patients with co-existing MSK conditions may not respond to CSI as well as those without. Injections into the Greater Trochanteric Bursa may have longer lasting benefit. Further research is needed on the use of USS imaging findings and image guidance. / This work was completed as part of a pre-doctoral fellowship funded by the National Institute of Health Research [NIHR301938, 2021].

O estudo fez comparações entre a intensidade e a distribuição das deformações a que fica submetido o fêmur proximal intacto e o fêmur proximal fraturado e implantado com o sistema parafuso deslizante Dynamic Hip Screw – DHS, em fraturas transtrocantéricas do tipo 31 - A2 – 2. Para isso, foram produzidas deformações, mediante carregamentos cíclicos, em fadiga. As amostras constituíram-se de ossos de fêmur sintéticos, intactos, e de ossos de fêmur sintéticos onde foram feitos cortes em laboratório produzindo situações de fratura do tipo 31 –A2.2. Nas amostras fraturadas foram colocadas as placas DHS simulando situações reais de osteossíntese. Os conjuntos de ossos mais placas foram então submetidos a ensaios de fadiga. Os resultados demonstraram que as presenças da fratura e do implante DHS alteraram a amplitude das deformações em todas as regiões do fêmur. Houve absorção da carga pelo implante DHS em todas as regiões de medição. Na região do colo femoral, o DHS absorveu 98% da carga, na região lateral 97%, no centro medial transversal 48%, no centro medial longitudinal 92%, no centro medial a 45 graus 94%, no calcar, antes da linha da fratura, 80%, na região do calcar, depois da linha da fratura, 81%, na região do segundo parafuso cortical transversal 81%, na região do segundo parafuso cortical longitudinal 73% e na região do segundo parafuso cortical a 45 graus 92%. A região do centro do pino guia e a região do segundo parafuso cortical foram as regiões de maior instabilidade mecânica. Para as condições de fratura do tipo 31 – A2.2 o implante do tipo DHS não absorve totalmente as deformações geradas, apresentando mobilidade do foco da fratura. Pequenas oscilações entre os ensaios causaram modificações importantes nos resultados, indicando que a relação ponto de medição ou a posição exata do implante podem implicar num desgaste ou afrouxamento prematuro do mesmo devido a uma sobrecarga. / The study compared the intensity and distribution of the deformations to the intact proximal femur and the proximal femur fractured and implanted with the slide screw system, Dynamic Hip Screw – DHS, in transtrochanteric fractures, 31 – A2 – 2 type. In this way, deformations were produced, by means of cyclic loads, in fatigue. The samples consisted of synthetic femoral bones intact and synthetic femoral bones that were cut in the laboratory producing fracture situations of type 31 – A2.2 type. In the fractured samples the DHS plates were placed simulating real osteosynthesis situations. The bone sets and plaques were then subjected to fatigue testing. The results showed that the presence of fracture and DHS implant altered the amplitude of deformations in all regions of the femur. The load was absorbed by the DHS implant in all measurement regions. In the femoral neck region, DHS absorbed 98% of the load, in the lateral region 97%, in the medial center – transverse – 48%, in the medial center – longitudinal – 92%, in the medial center – 45 degrees – 94%, in the calcar region, before the fracture line 80%, in the calcar region, after the fracture line, 81%, in the region of the second cortical screw – transverse – 81%, in the region of the second cortical screw – longitudinal – 73% and in the region of the second cortical screw – 45 degrees – 92% . The region of the center of the guide pin and the region of the second cortical screw were the regions of greater mechanical instability. For fracture conditions of type 31 - A2.2, the DHS type implant does not totally absorb the generated deformations, presenting mobility of the fracture focus. Small oscillations between the tests caused significant changes in the results, indicating that the relationship between the point of measurement and the exact position of the implant may lead to premature wear or loosening of the implant due to an overload.

Greater trochanteric pain (GTP) is a regional pain syndrome characterized by lateral hip pain and tenderness. Its incidence after total hip arthroplasty (THA) is variable. Bursal inflammation, degenerative changes of the attachment of the gluteal muscles, direct operative trauma and biomechanical disturbance of the operated hip have been discussed as being related to GTP. The diagnosis is purely clinical because radiological and laboratory investigations show no definite pathology. Although most treatment modalities are conservative, some patients may develop refractory complaints leading to surgical intervention. In study I we studied the incidence of GTP in 172 consecutive patients who underwent THA during 2002 at Sundsvall Hospital. Patients with GTP (n=21, incidence 12%) were matched with controls from the same cohort. The THA outcome was assessed using the Western Ontario and McMaster Universities Arthrosis (WOMAC) Index. Trochanteric tenderness was studied using an electronic pressure algometer. We found an association between the occurrence of GTP and postoperative uncorrected lengthening of the operated limb of ≥ one centimetre. The WOMAC index revealed a reduction of the clinical outcome in the GTP group. In Study II we tested the value of using an algometer in the diagnosis of GTP after THA. We measured the pressure-pain threshold (PPT) over the greater trochanter and ilio-tibial band in 18 patients and 18 matched controls. Both groups were evaluated using the visual analogue scale (VAS). We found the algometer to have a good predictive validity and reproducibility. However, there was large inter-individual variability across subjects. The PPT ratio of 0.8 (affected vs. unaffected side) can be used as a cutoff ratio to establish GTP. There was no correlation between PPT measurements and VAS. Because of a low positive predictive value and large inter-individual variability, the pressure algometer has a limited value as a screening tool. In study III we proposed a new surgical treatment for refractory GTP after THA consisting of distal lengthening of the ilio-tibial band (ITB) by Z-plasty under local anaesthesia. This method was used in 12 women between March 2004 and June 2006. The patients were followed up by phone interview 3-4 months postoperatively and by an EQ-5D questionnaire and clinical examination including evaluation with the algometer at 1-3 years postoperatively. We found that the patients‘ quality of life was markedly improved following the operation (EQ-5D = 0.26 preoperatively vs. 0.67 postoperatively; p <0.005). There were no postoperative complications. In study IV we evaluated the accuracy of a commonly used clinical method of LLD measurement (anterior superior iliac spine-medial malleolus) by comparing it to a reliable radiological method (tear drop-lesser trochanter) in 139 patients before and after THA. We found the correlation between the clinical and radiological methods to be weak preoperatively (r=0.21, ICC= 0.33) while the correlation was moderate postoperatively (r= 0.45, ICC=0.62). It is therefore recommended that the radiological method be used to measure leg length discrepancy in patients who undergo THA.

O estudo fez comparações entre a intensidade e a distribuição das deformações a que fica submetido o fêmur proximal intacto e o fêmur proximal fraturado e implantado com o sistema parafuso deslizante Dynamic Hip Screw – DHS, em fraturas transtrocantéricas do tipo 31 - A2 – 2. Para isso, foram produzidas deformações, mediante carregamentos cíclicos, em fadiga. As amostras constituíram-se de ossos de fêmur sintéticos, intactos, e de ossos de fêmur sintéticos onde foram feitos cortes em laboratório produzindo situações de fratura do tipo 31 –A2.2. Nas amostras fraturadas foram colocadas as placas DHS simulando situações reais de osteossíntese. Os conjuntos de ossos mais placas foram então submetidos a ensaios de fadiga. Os resultados demonstraram que as presenças da fratura e do implante DHS alteraram a amplitude das deformações em todas as regiões do fêmur. Houve absorção da carga pelo implante DHS em todas as regiões de medição. Na região do colo femoral, o DHS absorveu 98% da carga, na região lateral 97%, no centro medial transversal 48%, no centro medial longitudinal 92%, no centro medial a 45 graus 94%, no calcar, antes da linha da fratura, 80%, na região do calcar, depois da linha da fratura, 81%, na região do segundo parafuso cortical transversal 81%, na região do segundo parafuso cortical longitudinal 73% e na região do segundo parafuso cortical a 45 graus 92%. A região do centro do pino guia e a região do segundo parafuso cortical foram as regiões de maior instabilidade mecânica. Para as condições de fratura do tipo 31 – A2.2 o implante do tipo DHS não absorve totalmente as deformações geradas, apresentando mobilidade do foco da fratura. Pequenas oscilações entre os ensaios causaram modificações importantes nos resultados, indicando que a relação ponto de medição ou a posição exata do implante podem implicar num desgaste ou afrouxamento prematuro do mesmo devido a uma sobrecarga. / The study compared the intensity and distribution of the deformations to the intact proximal femur and the proximal femur fractured and implanted with the slide screw system, Dynamic Hip Screw – DHS, in transtrochanteric fractures, 31 – A2 – 2 type. In this way, deformations were produced, by means of cyclic loads, in fatigue. The samples consisted of synthetic femoral bones intact and synthetic femoral bones that were cut in the laboratory producing fracture situations of type 31 – A2.2 type. In the fractured samples the DHS plates were placed simulating real osteosynthesis situations. The bone sets and plaques were then subjected to fatigue testing. The results showed that the presence of fracture and DHS implant altered the amplitude of deformations in all regions of the femur. The load was absorbed by the DHS implant in all measurement regions. In the femoral neck region, DHS absorbed 98% of the load, in the lateral region 97%, in the medial center – transverse – 48%, in the medial center – longitudinal – 92%, in the medial center – 45 degrees – 94%, in the calcar region, before the fracture line 80%, in the calcar region, after the fracture line, 81%, in the region of the second cortical screw – transverse – 81%, in the region of the second cortical screw – longitudinal – 73% and in the region of the second cortical screw – 45 degrees – 92% . The region of the center of the guide pin and the region of the second cortical screw were the regions of greater mechanical instability. For fracture conditions of type 31 - A2.2, the DHS type implant does not totally absorb the generated deformations, presenting mobility of the fracture focus. Small oscillations between the tests caused significant changes in the results, indicating that the relationship between the point of measurement and the exact position of the implant may lead to premature wear or loosening of the implant due to an overload.

O estudo fez comparações entre a intensidade e a distribuição das deformações a que fica submetido o fêmur proximal intacto e o fêmur proximal fraturado e implantado com o sistema parafuso deslizante Dynamic Hip Screw – DHS, em fraturas transtrocantéricas do tipo 31 - A2 – 2. Para isso, foram produzidas deformações, mediante carregamentos cíclicos, em fadiga. As amostras constituíram-se de ossos de fêmur sintéticos, intactos, e de ossos de fêmur sintéticos onde foram feitos cortes em laboratório produzindo situações de fratura do tipo 31 –A2.2. Nas amostras fraturadas foram colocadas as placas DHS simulando situações reais de osteossíntese. Os conjuntos de ossos mais placas foram então submetidos a ensaios de fadiga. Os resultados demonstraram que as presenças da fratura e do implante DHS alteraram a amplitude das deformações em todas as regiões do fêmur. Houve absorção da carga pelo implante DHS em todas as regiões de medição. Na região do colo femoral, o DHS absorveu 98% da carga, na região lateral 97%, no centro medial transversal 48%, no centro medial longitudinal 92%, no centro medial a 45 graus 94%, no calcar, antes da linha da fratura, 80%, na região do calcar, depois da linha da fratura, 81%, na região do segundo parafuso cortical transversal 81%, na região do segundo parafuso cortical longitudinal 73% e na região do segundo parafuso cortical a 45 graus 92%. A região do centro do pino guia e a região do segundo parafuso cortical foram as regiões de maior instabilidade mecânica. Para as condições de fratura do tipo 31 – A2.2 o implante do tipo DHS não absorve totalmente as deformações geradas, apresentando mobilidade do foco da fratura. Pequenas oscilações entre os ensaios causaram modificações importantes nos resultados, indicando que a relação ponto de medição ou a posição exata do implante podem implicar num desgaste ou afrouxamento prematuro do mesmo devido a uma sobrecarga. / The study compared the intensity and distribution of the deformations to the intact proximal femur and the proximal femur fractured and implanted with the slide screw system, Dynamic Hip Screw – DHS, in transtrochanteric fractures, 31 – A2 – 2 type. In this way, deformations were produced, by means of cyclic loads, in fatigue. The samples consisted of synthetic femoral bones intact and synthetic femoral bones that were cut in the laboratory producing fracture situations of type 31 – A2.2 type. In the fractured samples the DHS plates were placed simulating real osteosynthesis situations. The bone sets and plaques were then subjected to fatigue testing. The results showed that the presence of fracture and DHS implant altered the amplitude of deformations in all regions of the femur. The load was absorbed by the DHS implant in all measurement regions. In the femoral neck region, DHS absorbed 98% of the load, in the lateral region 97%, in the medial center – transverse – 48%, in the medial center – longitudinal – 92%, in the medial center – 45 degrees – 94%, in the calcar region, before the fracture line 80%, in the calcar region, after the fracture line, 81%, in the region of the second cortical screw – transverse – 81%, in the region of the second cortical screw – longitudinal – 73% and in the region of the second cortical screw – 45 degrees – 92% . The region of the center of the guide pin and the region of the second cortical screw were the regions of greater mechanical instability. For fracture conditions of type 31 - A2.2, the DHS type implant does not totally absorb the generated deformations, presenting mobility of the fracture focus. Small oscillations between the tests caused significant changes in the results, indicating that the relationship between the point of measurement and the exact position of the implant may lead to premature wear or loosening of the implant due to an overload.

Abstract The purposes of the present research were (1) to analyse and characterize the hip fractures treated at Oulu University Hospital during a one-year period using the special forms of the Standardized Audit of Hip Fractures in Europe (SAHFE) and to evaluate their value for quality control, (2) to compare gamma nail (GN) and dynamic hip screw (DHS) fixation for the treatment of trochanteric hip fractures, focusing especially on the functional aspects, (3) to compare the short-term outcome of gamma nail (GN) and dynamic hip screw (DHS) fixation for the treatment of subtrochanteric hip fractures, and (4) to examine the rate and reliability of the classification of basicervical hip fractures and the outcome of the operative methods used for their treatment. Oulu University Hospital joined the Swedish Hip Fracture Project (Rikshöft), aimed at developing the quality control of hip fracture treatment, in 1989, and this later evolved into a project called the Standardized Audit of Hip Fractures in Europe (SAHFE), funded by the European Commission. Registration of hip fractures on the SAHFE forms was common practise in Oulu from 1st September 1997 until the end of December 2003. SAHFE data collection forms were used in all four studies belonging to this thesis. There were 238 hip fracture patients during the one-year period of registration at Oulu University Hospital. The intracapsular / extracapsular fracture rate (60/40) and the female/male rate (80/20) seemed to be similar to those reported in the recent Finnish Health Care Register data. The most frequent method for treating cervical fractures was Austin-Moore hemiarthroplasty (68%) and that for trochanteric and subtrochanteric fractures GN fixation (86%). The SAHFE forms proved to be easy to use and practicable for evaluating the quality of hip fracture treatment. In a matched-pair study the short-term outcomes of the treatment of trochanteric fractures (after 4 months) were slightly better in the DHS group than in the GN group with respect to walking ability and mortality. The difference in mortality was at least partly due to the higher number of complications requiring re-operations associated with GN fixation. In the treatment of subtrochanteric hip fractures, there were four intraoperative complications (9.3%) in the GN group but none in the DHS group. On the other hand, postoperative complications were more common in the DHS group (20% vs. 2%). It is significant that all these complications in the DHS group occurred in Seinsheimer type IIIA fractures. It is concluded that, despite the perioperative problems associated with gamma nailing, this technique may be preferable to DHS fixation for specific fracture types with medial cortical comminutation, such as Seinsheimer type IIIA. Altogether 108 of the 1624 hip fractures were initially classified by the surgeons as basicervical fractures, but after a careful second look only 30 fulfilled all the criteria. The definitive rate of basicervical fractures was thus 1.8%. Treatment of basicervical fractures as trochanteric fractures proved superior to their treatment as cervical fractures, resulting in lower re-operation rates. In conclusions; this thesis suggests that SAHFE forms are very useful for evaluating the quality of hip fracture treatment. Both GN fixation and DHS fixation are effective methods for the treatment of trochanteric hip fractures in elderly patients; in less comminuted fractures, the DHS method is the preferred method of treatment whereas GN fixation is alternative treatment for more comminuted fractures. GN fixation is preferable for the subtrochanteric fratures. Basicervical fractures shoud be regarded clinically as extracapsular fractures and managed in a similar manner to trochanteric fractures.

Abstract The current benchmark for the assessment of fracture risk is the status of osteoporosis based on the measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). However, DXA-based BMD has been shown to lack predictive ability for individual fracture risk. More than half of the hip fractures occur among people who are not classified as having osteoporosis. Osteoporosis (i.e. reduced bone mass) is only one risk factor for a fracture. In addition to bone mass, the mechanical strength of a bone is influenced by material and structural factors. However, we have limited information about the combined effects of BMD and bone structural properties in the evaluation of fracture risk, with regard to different types of hip fractures in particular. Therefore, this study investigated the radiograph-based structural factors of the upper femur for the assessment of bone mechanical competence and cervical and trochanteric hip fracture risk. The subjects of the clinical study comprised 74 postmenopausal women with non-pathologic cervical or trochanteric hip fracture and 40 age-matched controls. The impact of bone structure on the bone mechanical competence was studied using the experimental material of 140 cadaver femurs. The femora were mechanically tested in order to determine the failure load in a side impact configuration, simulating a sideways fall. In all study series, standard BMD measurements were performed, and the structural parameters of bone were determined from digitized plain radiographs. The present study showed that the large variation in the mechanical competence of bone is associated with the geometrical and architectural variation of bone. Moreover, the results strongly suggested that the etiopathology of different types of hip fractures significantly differs, and that fracture risk prediction should thus be performed separately for the cervical and trochanteric hip fractures. Furthermore, the study implied that the current clinical procedure can better be used for the assessment of the risk of trochanteric fracture, whereas cervical fracture is more strongly affected by the geometrical factors than by BMD. Finally, radiograph-based structural parameters of trabecular bone and bone geometry predicted in vitro failure loads of the proximal femur with a similar accuracy as DXA, when appropriate image analysis technology was used. Thus, the technology may be suitable for further development and application in clinical fracture risk assessment.

Abstract Hip fracture is a significant problem in health care incurring major costs to society. Therefore, it is necessary to study fracture mechanisms and develop improved methods to estimate individual fracture risk. In addition to conventional bone density measurements, computational finite element (FE) analysis has been recognized as a valuable method for studying biomechanical characteristics of a hip fracture. In this study, computed tomography (CT) based finite element methods were investigated and simulation models were developed to estimate experimental femoral fracture load and hip fracture type in a sideways fall loading configuration. Cadaver femur specimens (age 55–100 years) were scanned using a CT scanner and dual-energy X-ray absorptiometry (DXA), and the femurs were mechanically tested for failure in a sideways fall loading configuration. CT images were used for generating the FE model, and DXA was used as a reference method. FE analysis was done for simulation models of the proximal femur in a sideways fall loading configuration to estimate the experimentally measured fracture load and fracture type. Statistical analyses were computed to compare the experimental and the FE data. Cervical and trochanteric hip fractures displayed characteristic strain patterns when using a FE model mainly driven by bone geometry. This relatively simple FE model estimation provided reasonable agreement for the occurrence of experimental hip fracture type. Accurate assessment between experimental and finite element fracture load (r2 =  0.87) was achieved using subject-specific modeling, including individual material properties of trabecular bone for bilinear elastoplastic FE models. Nevertheless, the study also showed that proximal femoral fracture load can be estimated with reasonable accuracy (r2 =  0.73) by a relatively simple FE model including only cortical bone. The cortical bone FE model was more predictive for fracture load than DXA and slightly less accurate than the subject-specific FE model. The accuracy and short calculation time of the model suggest promise in terms of effective clinical use. / Tiivistelmä Lonkkamurtuma on huomattava ongelma terveydenhuollossa aiheuttaen merkittäviä kustannuksia yhteiskunnalle. Tämän vuoksi on tärkeää tutkia ja kehittää uusia yksilöllisen murtumariskin arviointimenetelmiä. Elementtimenetelmä on tehokas laskennallinen työkalu lonkkamurtuman biomekaanisten ominaisuuksien tutkimisessa. Tässä työssä tutkittiin ja kehitettiin tietokonetomografiaan perustuvia reisiluun simulaatiomalleja kokeellisten murtolujuuksien ja lonkkamurtumatyyppien arviointiin. Reisiluunäytteet (ikä 55–100 vuotta) kuvattiin tietokonetomografialaitteella ja kaksienergisellä röntgenabsorptiometrialla, jonka jälkeen reisiluut kuormitettiin kokeellisesti murtolujuuden ja murtumatyypin määrittämiseksi sivuttaiskaatumisasetelmassa. Tietokonetomografialeikekuvia käytettiin simulaatiomallien luomiseen, ja kaksienergistä röntgenabsorptiometriaa käytettiin vertailumenetelmänä. Reisiluun simulaatiomallit analysoitiin elementtimenetelmän avulla kokeellisten murtolujuuksien ja murtumatyyppien arvioimiseksi. Tilastoanalyysiä käytettiin verrattaessa kokeellista aineistoa ja simulaatioaineistoa. Reisiluun muotoon perustuva simulaatiomalli osoitti, että reisiluun kaulan ja sarvennoisen murtumilla on tyypilliset jännitysjakaumat. Tämän suhteellisen yksinkertaisen mallin murtumatyyppi oli lähes yhdenmukainen kokeellisen murtumatyypin kanssa. Reisiluun kokeellinen murtolujuus pystyttiin arvioimaan tarkasti (r2 =  0.87) käyttäen yksityiskohtaista simulaatiomallia, joka sisältää yksilölliset hohkaluun materiaaliominaisuudet. Toisaalta murtolujuus pystyttiin arvioimaan kohtuullisella tarkkuudella (r2 =  0.73) melko yksinkertaisellakin mallilla, joka käsittää ainoastaan kuoriluun. Kuoriluuhun perustuva malli oli tarkempi arvioimaan reisiluun kokeellista murtolujuutta kuin kaksienerginen röntgenabsorptiometria ja lähes yhtä tarkka kuin yksityiskohtaisempi simulaatiomalli. Mallin tarkkuus ja lyhyt laskenta-aika antavat lupauksia tehokkaaseen kliiniseen käyttöön.

Abstract Hip fracture is the most severe complication of osteoporosis. The occurrence of hip fracture is increasing worldwide as a result of the ageing of the population. The clinical assessment of osteoporosis and to some extent hip fracture risk is based on the measurement of bone mineral density (BMD) using dual X-ray absorptiometry (DXA). However, it has been demonstrated that most hip fractures occurring after a fall involve non-osteoporotic populations and that the geometry plays a critical role in the fracture risk assessment. A potential alternative for the assessment of hip fracture risk is finite element modelling, which is a computational method allowing simulation of mechanical loading. The aim of this study was to investigate different finite-element (FE) methods for predicting hip fracture type and eventually hip failure load in the simulation of a fall on the greater trochanter. An experimental fall on the greater trochanter was performed on over 100 cadaver femurs in order to evaluate the failure load and fracture type. In all studies, assessment of BMD, measurement of geometrical parameters and generation of finite element models were performed using DXA, digitized plain radiographs and computed tomography scans. The present study showed that geometrical parameters differ between specific hip fracture types. FE studies showed feasible accuracy in the prediction of hip fracture type, even by using homogeneous material properties. Finally, a new method to generate patient-specific volumetric finite element models automatically from a standard radiographic picture was developed. Preliminary results in the prediction of failure load and fracture type were promising when compared to experimental fractures. / Tiivistelmä Lonkkamurtuma on osteoporoosin vakavin seuraus. Lonkkamurtumatapaukset kasvavat maailmanlaajuisesti väestön ikääntymisen myötä. Osteoporoosin ja osin myös lonkkamurtumariskin kliininen arviointi perustuu luun mineraalitiheyden mittaamiseen kaksienergisellä röntgenabsorptiometrialla (Dual-energy X-ray absorptiometry, DXA). On kuitenkin osoitettu, että suurin osa kaatumisen seurauksena tapahtuvista lonkkamurtumatapauksista tapahtuu henkilöillä joilla ei ole todettua osteoporoosia, ja että myös luun muoto on tärkeä tekijä arvioitaessa lonkkamurtumariskiä. Laskennallinen mallintaminen elementtimenetelmällä mahdollistaa mekaanisen kuormituksen simuloinnin ja on potentiaalinen vaihtoehto lonkkamurtumariskin arviointiin. Tämän työn tarkoituksena on tutkia elementtimenetelmiä lonkkamurtumatyypin ja lopulta lonkan murtolujuuden ennustamiseksi simuloimalla kaatumista sivulle. Yli sataa reisiluuta kuormitettiin kokeellisesti murtolujuuden ja murtumatyypin määrittämiseksi. Luun mineraalitiheyden arviointi, muotoparametrien mittaus ja elementtimallit tehtiin käyttäen DXA:a, digitalisoituja röntgenkuvia ja tietokonetomografiakuvia. Tämä tutkimus osoittaa, että luun muotoparametrit vaihtelevat eri lonkkamurtumatyyppien välillä. Lonkkamurtumatyyppi voitiin ennustaa hyvällä tarkkuudella elementtimenetelmän avulla silloinkin, kun käytettiin homogeenisia materiaaliominaisuuksia. Lopuksi kehitettiin uusi menetelmä yksilöllisten kolmiulotteisten elementtimallien automaattiseen luontiin tavallisista röntgenkuvista. Alustavat tulokset lonkan murtolujuuden ja murtumatyypin ennustamisessa ovat lupaavia.

No description available.