Journal articles on the topic 'Femoral implants'
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Pluhar, E., C. P. Skurla, E. L. Egger, S. P. James, and D. J. Frankel. "Radiographic evaluation of mechanically tested cemented total hip arthroplasty femoral components retrieved post-mortem." Veterinary and Comparative Orthopaedics and Traumatology 17, no. 04 (2004): 216–24. http://dx.doi.org/10.1055/s-0038-1632816.
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SummaryGuidelines for assessing total hip arthroplasty (THA) radiographs for femoral implant stability have not been published; therefore, often the determination is subjective. The aim of this study was to identify radiographic criteria for veterinary clinicians to use when evaluating radiographs for femoral implant stability. Specific objectives were to: identify radiographic features associated with canine THA femoral implant loosening, evaluate whether technical recommendations for human femoral component implantation apply to dogs, and evaluate the effectiveness of radiographs for identifying canine THA implant loosening. Post-operative, follow-up, and post-mortem contact radiographs of canine implanted femora retrieved postmortem and mechanically tested for implant stability were evaluated. Based on the results, radiographic evaluation is not an effective means of assessing canine femoral implant stability; however, certain radiographic findings including implant retroversion, cement mantle cracks, or the appearance of cementmetal interface radiolucencies, may be indicative of implant loosening. It was also found that femoral implants completely surrounded by cement mantle of any thickness were less likely to loosen than those with an area lacking cement between the implant and bone. There was also a trend suggesting an association between inferior cement mantle quality and femoral implant loosening. In order to improve cement mantle quality and ensure that implants are completely surrounded by cement mantle, the use of modern cementing techniques is recommended.
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Klyuchevskiy, V. V., Sergey Il'suverovich Gil'fanov, V. V. Danilyak, M. V. Belov, M. A. Khudaybergenov, I. V. Klyuchevskiy, V. V. Klyuchevskiy, et al. "Joint Replacement in Femoral Neck Fractures." N.N. Priorov Journal of Traumatology and Orthopedics 16, no. 3 (September 15, 2009): 21–25. http://dx.doi.org/10.17816/vto200916321-25.
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Results of joint replacement in femoral neck fractures have been analyzed. During the period from 1994 to 2003 total hip replacement was performed to 399 patients with subcapital fractures including 372 patients in whom the operation was performed as a primary intervention. From 2002 to 2004 the total number of 290 hemiarthroplasty operations with use of module native implant was performed in 286 patients aged 76-101 years. In total joint replacement group intrahospital lethality made up 2% due to the following causes: pulmonary thrombembolia - 3 cases, acute cardiac insufficiency - 1 case, deep decubitus ulcers resulting in sepsis - 2 cases, polyorganic insufficiency on the background of severe concomitant pathology - 1 case. In the early postoperative period the following complications were noted: implant dislocation (5.2% of cases), intraoperative femoral fracture (3.5%). Infectious complications developed in 2 patients and in both cases removal of the implant was required. With mean-term follow-up native implants showed mean-term survival of 92-94% in 272 patients. Mean evaluation by Harris was the following: biometric «Sinko» and «ESI» implants - 83.1 points, PF «Sinko» implants - 89.3 points, combination of «Mathys» friction pair with native femoral component - 91.2 points. «Mathys» implants showed 94.6 points. Results of ЯРТЕЗ joint replacement were evaluated during the period from 1 to 3 years in 183 patients. Intrahospital lethality made up 1.8%. Excellent and good results were achieved in 53.7% of patients. Revision was required in 1.5% of cases. As concluded total hip replacement in femoral neck fracture was the effective treatment technique. It was reasonable both cement and cementless fixation with various implants for the optimum choice of implant in every specific patient. Use of modern module implants enabled to expand the indications for application of arthroplasty in elderly patients.
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Wu, Xinlei, Ming Yang, Lijun Wu, and Wenxin Niu. "A Biomechanical Comparison of Two Intramedullary Implants for Subtrochanteric Fracture in Two Healing Stages: A Finite Element Analysis." Applied Bionics and Biomechanics 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/475261.
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Background. The biomechanical effect of two implants, namely, proximal femoral nail antirotation for Asia (PFNA-II) and Expert Asian Femoral Nail (A2FN), for treating subtrochanteric fracture during healing stages, is still unclear.Methods. A 3D finite element model of an intact femur was constructed and validated. The fractured and postoperative models were accordingly produced. The postoperative models were loaded with the peak joint forces during gait for the soft and hard callus stages. The effects of stress distribution on the implants, femoral head and callus, and the deformation of the proximal femur were examined.Results. Both implants showed similar biomechanical effect in two healing stages. As the healing duration increased, the von Mises stress of two implants and the tensile stress of the femoral head decreased, whereas the compressive stress of the femoral head increased. However, the PFNA-II operation resulted in higher stress on the implant, lower stress on the proximal femur, and lower compressive stress and higher tensile stress on the callus than A2FN operation.Conclusions. The A2FN implant may provide a biomechanically superior construct for subtrochanteric fracture healing. However, the upper screw of the A2FN implant may be more likely to be loose in the healing process.
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Kopec, Mateusz, Adam Brodecki, Grzegorz Szczęsny, and Zbigniew L. Kowalewski. "Microstructural Analysis of Fractured Orthopedic Implants." Materials 14, no. 9 (April 25, 2021): 2209. http://dx.doi.org/10.3390/ma14092209.
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In this paper, fracture behavior of four types of implants with different geometries (pure titanium locking plate, pure titanium femoral implant, Ti-6Al-4V titanium alloy pelvic implant, X2CrNiMo18 14-3 steel femoral implant) was studied in detail. Each implant fractured in the human body. The scanning electron microscopy (SEM) was used to determine the potential cause of implants fracture. It was found that the implants fracture mainly occurred in consequence of mechanical overloads resulting from repetitive, prohibited excessive limb loads or singular, un-intendent, secondary injures. Among many possible loading types, the implants were subjected to an excessive fatigue loads with additional interactions caused by screws that were mounted in their threaded holes. The results of this work enable to conclude that the design of orthopedic implants is not fully sufficient to transduce mechanical loads acting over them due to an increasing weight of treated patients and much higher their physical activity.
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Suetoshi, Ryoichi, Dorian Cretin, Shinji Ogawa, and Takayoshi Nakano. "Assessment of the Elastic Properties of Human Femoral Bone with Artificial Hip Joint by Ultrasound Transmission." Key Engineering Materials 529-530 (November 2012): 321–24. http://dx.doi.org/10.4028/www.scientific.net/kem.529-530.321.
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Following artificial hip joint implantation, a stress inhibition, applied to bone in the surroundings of implants, causes a structural change in bone called bone loss. To evaluate the bone mechanical characteristics, it is essential to investigate the elastic properties of cortical bone. In this article a pair of donor femora was investigated, one with an implant and the other without. Differences in Speed of Sound (SOS), a parameter reflecting elastic properties, were measured in both femora by ultrasound transmission. As a result, in almost all areas, the femur that was implanted showed significantly lower cortical SOS. Our results indicated that the change in the mechanical function of bone, due to the introduction of femoral implants, could be evaluated by the measurement of SOS.
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Abdelaal, Osama, Saied Darwish, Hassan El-Hofy, and Yoshio Saito. "Patient-specific design process and evaluation of a hip prosthesis femoral stem." International Journal of Artificial Organs 42, no. 6 (December 11, 2018): 271–90. http://dx.doi.org/10.1177/0391398818815479.
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Introduction: There are several commercially available hip implant systems. However, for some cases, custom implant designed based on patient-specific anatomy can offer the patient the best available implant solution. Currently, there is a growing trend toward personalization of medical implants involving additive manufacturing into orthopedic medical implants’ manufacturing. Methods: This article introduces a systematic design methodology of femoral stem prosthesis based on patient’s computer tomography data. Finite element analysis is used to evaluate and compare the micromotion and stress distribution of the customized femoral component and a conventional stem. Results: The proposed customized femoral stem achieved close geometrical fit and fill between femoral canal and stem surfaces. The customized stem demonstrated lower micromotion (peak: 21 μm) than conventional stem (peak: 34 μm). Stress results indicate up to 89% increase in load transfer by conventional stem than custom stem because the higher stiffness of patient-specific femoral stem proximally increases the custom stem shielding in Gruen’s zone 7. Moreover, patient-specific femoral stem transfers the load widely in metaphyseal region. Conclusion: The customized femoral stem presented satisfactory results related to primary stability, but compromising proximo-medial load transfer due to increased stem cross-sectional area increased stem stiffness.
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Mihai, Simona, and Viviana Filip. "New Design Concept for Reducing Torque Wear on Implant." Applied Mechanics and Materials 658 (October 2014): 453–58. http://dx.doi.org/10.4028/www.scientific.net/amm.658.453.
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The hip (coxofemoral) joint is built so as to provide, at the same time, maximum stability and mobility, and is characterized by a very low wear rate and very low frictional forces thanks to the very good natural lubrication. In time, due to various reasons such as aging, joint illnesses, bone tumors, arthritis, injuries, coxofemoral joints may lose their self-lubrication ability, causing pains that make movement almost impossible. The therapeutic solution for coxofemoral joint illnesses is hip implant arthroplasty. Medical implants replacing the bone segments of coxofemoral joints are subjected to mechanical stress during walking and daily activities, which leads to wear in the long run. In the (most frequent) case of a bipolar hip implant, consisting of a femoral stem and femoral head, the area most affected by wear is the hip implant coupling, which represents the connection between the sphere-shaped proximal end of the femoral stem and the femoral head’s ball groove. Typically, the spherical proximal end of the femoral stem is made of metallic biomaterials (titanium and titanium alloys, cobalt-based alloys, stainless steels) or ceramic biomaterials (alumina, zirconia), while the femoral head’s ball groove is made of polymeric biomaterials (high-density polyethylene), metallic biomaterials or ceramic biomaterials. In the hip implant’s coupling there takes place a sliding friction whose coefficient depends on the nature of the touching surfaces (metal on metal, metal on polyethylene, ceramic on polyethylene, ceramic on ceramic). The wear that occurs in the coupling is due especially to the particles of material detached from the surfaces coming into contact. A worn coupling should be replaced by a revision surgery that the patient must go through, since loose particles generate severe joint inflammation. The objective of this paper is: -to point out the wear degree of the components forming the friction coupling of a hip implant, by presenting images, as seen on a video microscope, of two implants retrieved from patients after revision surgery -to present a new structural option for the construction of a hip implant coupling, by introducing two ball cages that replace the femoral head’s ball groove, which reduces the contact surface and replaces sliding friction with rolling friction (with a lower friction coefficient), thus diminishing the wear on the implant coupling.
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Basudan, Amani M., Marwa Y. Shaheen, Abdurahman A. Niazy, Jeroen J. J. P. van den Beucken, John A. Jansen, and Hamdan S. Alghamdi. "Effect of Osteoporosis on Well-Integrated Bone Implants." Applied Sciences 11, no. 2 (January 13, 2021): 723. http://dx.doi.org/10.3390/app11020723.
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The installation of dental implants has become a common treatment for edentulous patients. However, concern exists about the influence of osteoporosis on the final implant success. This study evaluated whether an ovariectomy (OVX)-induced osteoporotic condition, induced eight weeks postimplantation in a rat femoral condyle, influences the bone response to already-integrated implants. The implants were inserted in the femoral condyle of 16 female Wistar rats. Eight weeks postimplantation, rats were randomly ovariectomized (OVX) or sham-operated (SHAM). Fourteen weeks later, animals were sacrificed, and implants were used for histological and histomorphometric analyses. A significant reduction in the quantity and quality of trabecular bone around dental implants existed in OVX rats in comparison to the SHAM group. For histomorphometric analysis, the bone area (BA%) showed a significant difference between OVX (34.2 ± 4.3) and SHAM (52.6 ± 12.7) groups (p < 0.05). Bone–implant contact (BIC%) revealed significantly lower values for all implants in OVX (42.5 ± 20.4) versus SHAM (59.0 ± 19.0) rats. Therefore, induction of an osteoporotic condition eight weeks postimplantation in a rat model negatively affects the amount of bone present in close vicinity to bone implants.
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Басов, A. Basov, Шпаковский, M. Shpakovskiy, Грибанов, N. Gribanov, Ардашев, et al. "Use of the Drug "Perphtoran" and Bioactive Implants with Calcium Phosphate Coating in Surgical Treatment of Femoral Neck Fractures at the Experiment." Journal of New Medical Technologies 22, no. 3 (September 15, 2015): 73–79. http://dx.doi.org/10.12737/13304.
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The purpose of the study was to improve the results of surgical treatment of femoral neck fractures by in-tra-osseous injection of oxygenated perphtoran in avascular femoral head and osteosynthesis implants with bioactive calcium phosphate coating in the experiment.
Investigations were carried out on 68 male rabbits. Hip fracture was formed transcervically by osteotome and crosses private ligament of the femoral head. The authors studied the dynamics of radiological and morphological parameters of reparative osteogenesis in 3 groups of animals: the 1st group with the introduction of oxygenated perftoran in an avascular femoral head without osteosynthesis of the femoral neck; the 2nd group after osteosynthesis by implants with bioactive calcium phosphate coating; the 3rd group after injection of oxygenated perftoran in an avascular femoral head with osteosynthesis implants by bioactive calcium phosphate coating.
In the group without osteosynthesis process the authors revealed the development of degenerative changes with bone resorption, the expansion of the fracture line, displacement of bone fragments and the formation of non-union of the femoral neck. Osteosynthesis of femoral neck fractures with calcium phosphate bioactive implants coating contributes to fracture healing. Analysis of the results of the morphological assessment of the perftoran effect of calcium phosphate coatings on reparative osteogenesis in experimental hip fracture allows to determine the less severe exudative phase of the inflammatory response and to accelerate bone formation in the group with oxygenated perftoran and titanium implants coated with calcium phosphate.
Introduction of oxygenated perftoran in an avascular femoral head at the osteosynthesis of experimental hip fractures by bioactive implants coated with calcium phosphate promotes to bone regeneration processes on the basis of radiological and morphological data. This allows to fracture healing at an earlier date by reducing inflammatory infiltration in the area of the fracture and the direct inclusion of the implant with calcium phosphate coating in the process of reparative osteogenesis.
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Cox, India, Louay Al Mouazzen, Sabri Bleibleh, Radu Moldovan, Fiona Bintcliffe, C. Edward Bache, and Simon Thomas. "Combined two-centre experience of single-entry telescopic rods identifies characteristic modes of failure." Bone & Joint Journal 102-B, no. 8 (August 2020): 1048–55. http://dx.doi.org/10.1302/0301-620x.102b8.bjj-2020-0131.r1.
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Aims The Fassier Duval (FD) rod is a third-generation telescopic implant for children with osteogenesis imperfecta (OI). Threaded fixation enables proximal insertion without opening the knee or ankle joint. We have reviewed our combined two-centre experience with this implant. Methods In total, 34 children with a mean age of five years (1 to 14) with severe OI have undergone rodding of 72 lower limb long bones (27 tibial, 45 femoral) for recurrent fractures with progressive deformity despite optimized bone health and bisphosphonate therapy. Data were collected prospectively, with 1.5 to 11 years follow-up. Results A total of 24 patients (33%) required exchange of implants (14 femora and ten tibiae) including 11 rods bending with refracture. Four (5%) required reoperation with implant retention. Loss of proximal fixation in the femur and distal fixation in the tibia were common. Four patients developed coxa vara requiring surgical correction. In total, 13 patients experienced further fractures without rod bending; eight required implant revision. There was one deep infection. The five-year survival rate, with rod revision as the endpoint, was 63% (95% confidence interval (CI) 44% to 77%) for femoral rods, with a mean age at implantation of 4.8 years (1.3 to 14.8), and 64% (95% CI 36% to 82%) for tibial rods, with a mean age at implantation of 5.2 years (2.0 to 13.8). Conclusion FD rods are easier to implant but do not improve on the revision rates reported for second generation T-piece rods. Proximal femoral fixation is problematic in younger children with a partially ossified greater trochanter. Distal tibial fixation typically fails after two years. Future generation implants should address proximal femoral and distal tibial fixation to avoid the majority of complications in this series. Cite this article: Bone Joint J 2020;102-B(8):1048–1055.
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Hernández-Cortés, Pedro, Alberto Monje, Pablo Galindo-Moreno, Andrés Catena, Inmaculada Ortega-Oller, José Salas-Pérez, Francisco Mesa, et al. "AnEx VivoModel in Human Femoral Heads for Histopathological Study and Resonance Frequency Analysis of Dental Implant Primary Stability." BioMed Research International 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/535929.
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Objective. This study was designed to explore relationships of resonance frequency analysis (RFA)—assessed implant stability (ISQ values) with bone morphometric parameters and bone quality in anex vivomodel of dental implants placed in human femoral heads and to evaluate the usefulness of this model for dental implant studies.Material and Methods. Thisex vivostudy included femoral heads from 17 patients undergoing surgery for femoral neck fracture due to osteoporosis (OP) (n=7) or for total prosthesis joint replacement due to severe hip osteoarthrosis (OA) (n=10). Sixty4.5×13 mm Dentsply Astra implants were placed, followed by RFA. CD44 immunohistochemical analysis for osteocytes was also carried out.Results. As expected, the analysis yielded significant effects of femoral head type (OA versus OA) (P<0.001), but not of the implants (P=0.455) or of the interaction of the two factors (P=0.848). Bonferroni post hoc comparisons showed a lower mean ISQ for implants in decalcified (50.33±2.92) heads than in fresh (66.93±1.10) or fixated (70.77±1.32) heads (bothP<0.001). The ISQ score (fresh) was significantly higher for those in OA (73.52±1.92) versus OP (67.13±1.09) heads. However, mixed linear analysis showed no significant association between ISQ scores and morphologic or histomorphometric results (P>0.5in all cases), and no significant differences in ISQ values were found as a function of the length or area of the cortical layer (bothP>0.08).Conclusion. Although RFA-determined ISQ values are not correlated with morphometric parameters, they can discriminate bone quality (OP versus OA). Thisex vivomodel is useful for dental implant studies.
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Wilson, Lance J., John A. Roe, Mark J. Pearcy, and Ross W. Crawford. "Shortening Cemented Femoral Implants." Journal of Arthroplasty 27, no. 6 (June 2012): 934–39. http://dx.doi.org/10.1016/j.arth.2011.10.012.
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Jafarov, Afgan, Fatma Kübra Erbay Elibol, Chingiz Alizadeh, Mahir Gülşen, Emre Toğrul, and Teyfik Demir. "Perforated H-beam implant can be used in femoral neck fracture." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 233, no. 3 (February 3, 2019): 354–61. http://dx.doi.org/10.1177/0954411919827041.
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This biomechanical study evaluated comparison osteosynthesis of the femoral neck fracture model by 3 cannulated screw implants and new perforated H beam implants under different loading conditions with 45 third generation right proximal femur bones. A standardized Pauwels Type 3 of the femoral neck fracture was performed in the femur models. For assessing the rigidity and strength of fixation methods, the proximal femur bones after their osteosynthesis were then mechanically tested in axial compression, and torsional and dynamic axial compression loading. To determine the structural advantage of the new implant system, perforated and nonperforated new implant systems were comparing about pull out performance. When loading the samples, photographs were taken continuously. The reference parameters were described and measured from unloaded and loaded photographs of the static and dynamic tests. There was no significant difference between stiffness values of two fixation methods under static and rotational loading. Under dynamic loading, the displacement of the superior point of femoral head at the fracture line showed a significant decrease between the new implant system and cannulated screws. Comparing the relative motion at the mid line of the fracture in femoral neck between groups, a significant increase was found in H Beam implant group. Perforated H beam implants have similar static and torsion properties with golden standard. Although there was significant difference under dynamic loading which simulate movement early after surgery, the patient was not allowed to move early after surgery in the clinical practice. Therefore, the differences due to the perforated “H” beam implant would not cause clinical insecurity. Therefore, it is assumed that the perforated “H” beam implant can be used for internal fixation as an alternative to cannulated screws in the treatment of instable femoral neck fracture.
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Markopoulos, Angelos P., Nikolaos E. Karkalos, Nikolaos I. Galanis, and Dimitrios E. Manolakos. "Design and Machining of the Femoral Component of Total Knee Implant." Solid State Phenomena 261 (August 2017): 313–20. http://dx.doi.org/10.4028/www.scientific.net/ssp.261.313.
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Manufacturing of medical implants constitutes always a challenge, regarding the constraints involved for these applications, e.g. need for suitable materials or appropriate dimensional tolerances. The aforementioned pose also challenges for the machining process itself, regarding the appropriate machining conditions and machine tool setup and so it is considered as a subject of interest. In the present work, the manufacturing process for knee implants, especially for the femoral component of this type of implants, is discussed, encompassing all the stages from design and planning of each step of the process up to actual machining of the implant component. Finally, the surface quality of the implant after finishing process is assessed for each of the three different finishing processes applied, in order to determine the suitable machining parameters required.
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Bhatt, Himanshu, and Tarun Goswami. "Safe zones in hip-implant designs to resist." Research on Intelligent Manufacturing and Assembly 1, no. 1 (October 12, 2022): 20–27. http://dx.doi.org/10.25082/rima.2022.01.003.
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Major contributing parameters to hip implant dislocation include preoperative, intra-operative and post-operative factors. Implant geometry are design as well as non-design related. Femoral and acetabular component design features causing dislocation and/or resisting it are elucidated. Twelve implants were designed during this investigation were analyzed for dislocation resistance. A safe zone, establishes combinations of implant dimensions, was analyzed for all the 12 implants where implants were dislocation resistant. Head diameters between 26 mm to 32 mm, neck diameters closer to 14 mm, and neck angle between 25 to 35º were examined to be the safest ranges for hip implant designs.
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Radtke, Kerstin, Fabian Goede, Michael Schwarze, Peter Paes, Max Ettinger, and Bastian Welke. "Fixation Stability and Stiffness of Two Implant Systems for Proximal Femoral Varization Osteotomy." Applied Sciences 10, no. 17 (August 25, 2020): 5867. http://dx.doi.org/10.3390/app10175867.
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Proximal femoral varization osteotomy is a well-established surgical procedure in children with severe hip problems. This study aimed to evaluate the fixation stability and stiffness of two new implant systems. A biomechanical testing model was created with a total of 12 synthetic femora. Proximal femoral varization osteotomy was performed in every femur, and the synthetic femora were fixed with two different implant systems (PediLoc Locking Proximal Femur Plate System versus PediLoc Locking Cannulated Blade Plate System; OrthoPediatrics, Warsaw, IN, USA). The average torsional stiffness of the locking plate group was higher than for the cannulated blade plate group. Differences in internal and external rotations were seen between the two groups, but they were not significant. Using the tested implants in severe osteoporotic bones might show other results. Therefore, it might be helpful to use the locking plate system in osteoporotic bones and in cases of revision operations where stability is of critical focus.
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Freitag, Tobias, Michael Fuchs, Julia V. Woelfle-Roos, Heiko Reichel, and Ralf Bieger. "Mid-term migration analysis of a femoral short-stem prosthesis: a five-year EBRA-FCA-study." HIP International 29, no. 2 (May 9, 2018): 128–33. http://dx.doi.org/10.1177/1120700018772277.
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Introduction: The objective of this study was to evaluate the mid-term migration pattern of a femoral short stem. Methods: Implant migration of 73 femoral short-stems was assessed by Ein-Bild-Roentgen-Analysis Femoral-Component-Analysis (EBRA-FCA) 5 years after surgery. Migration pattern of the whole group was analysed and compared to the migration pattern of implants “at risk” with a subsidence of more than 1.5 mm 2 years postoperative. Results: Mean axial subsidence was 1.1 mm (–5.0 mm to 1.5 mm) after 60 months. There was a statistical significant axial migration until 2 years postoperative with settling thereafter. 2 years after surgery 18 of 73 Implants were classified “at risk.” Nevertheless, all stems showed secondary stabilisation in the following period with no implant failure neither in the group of implants with early stabilisation nor the group with extensive early onset migration. Conclusion: In summary, even in the group of stems with more pronounced early subsidence, delayed settling occurred in all cases. The determination of a threshold of critical early femoral short stem subsidence is necessary because of the differing migration pattern described in this study with delayed settling of the Fitmore stem 2 years postoperatively compared to early settling within the first postoperative year described for conventional stems.
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Knobe, Matthias, and Hans-Christoph Pape. "Anchorage strategies in geriatric hip fracture management." Innovative Surgical Sciences 1, no. 2 (December 1, 2016): 73–78. http://dx.doi.org/10.1515/iss-2016-0034.
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AbstractThere is an enormous humanitarian and socioeconomic need to improve the quality and effectiveness of care for patients with hip fracture. To reduce mechanical complications in the osteosynthesis of proximal femoral fractures, improved fixation techniques have been developed including blade or screw-anchor devices, locked minimally invasive or cement augmentation strategies. However, despite numerous innovations and advances regarding implant design and surgical techniques, systemic and mechanical complication rates remain high. Treatment success depends on secure implant fixation in often-osteoporotic bone as well as on patient-specific factors (fracture stability, bone quality, comorbidity, and gender) and surgeon-related factors (experience, correct reduction, and optimal screw placement in the head/neck fragment). For fracture fixation, the anchorage of the lag screw within the femoral head plays a crucial role depending on the implant’s design. Meta-analyses and randomized controlled studies demonstrate that there is a strong trend towards arthroplasty treating geriatric femoral neck fractures. However, for young adults as well as older patients with less compromised bone quality, or in undisplaced fractures, head-preserving therapy is preferred as it is less invasive and associated with good functional results. This review summarizes the evidence for the internal fixation of femoral neck fractures and trochanteric femoral fractures in elderly patients. In addition, biomechanical considerations regarding implant anchorage in the femoral head including rotation, migration, and femoral neck shortening are made. Finally, cement augmentation strategies for hip fracture implants are evaluated critically.
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Ghavidelnia, Naeim, Mahdi Bodaghi, and Reza Hedayati. "Femur Auxetic Meta-Implants with Tuned Micromotion Distribution." Materials 14, no. 1 (December 29, 2020): 114. http://dx.doi.org/10.3390/ma14010114.
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Stress shielding and micromotions are the most significant problems occurring at the bone-implants interface due to a mismatch of their mechanical properties. Mechanical 3D metamaterials, with their exceptional behaviour and characteristics, can provide an opportunity to solve the mismatch of mechanical properties between the bone and implant. In this study, a new porous femoral hip meta-implant with graded Poisson’s ratio distribution was introduced and its results were compared to three other femoral hip implants (one solid implant, and two porous meta-implants, one with positive and the other with a negative distribution of Poisson’s ratio) in terms of stress and micromotion distributions. For this aim, first, a well-known auxetic 3D re-entrant structure was studied analytically, and precise closed-form analytical relationships for its elastic modulus and Poisson’s ratio were derived. The results of the analytical solution for mechanical properties of the 3D re-entrant structure presented great improvements in comparison to previous analytical studies on the structure. Moreover, the implementation of the re-entrant structure in the hip implant provided very smooth results for stress and strain distributions in the lattice meta-implants and could solve the stress shielding problem which occurred in the solid implant. The lattice meta-implant based on the graded unit cell distribution presented smoother stress-strain distribution in comparison with the other lattice meta-implants. Moreover, the graded lattice meta-implant gave minimum areas of local stress and local strain concentration at the contact region of the implants with the internal bone surfaces. Among all the cases, the graded meta-implant also gave micromotion levels which are the closest to values reported to be desirable for bone growth (40 µm).
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Duncan, Warwick J., Sunyoung Ma, Allauddin Siddiqi, and Reham B. Osman. "Zirconia versus Titanium Implants: 8-Year Follow-Up in a Patient Cohort Contrasted with Histological Evidence from a Preclinical Animal Model." Materials 15, no. 15 (August 2, 2022): 5322. http://dx.doi.org/10.3390/ma15155322.
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Zirconia ceramic (ZC) implants are becoming more common, but comparisons between preclinical histology and long-term clinical trials are rare. This investigation comprised (1) 8-year clinical follow-up of one-piece ZC or titanium (Ti) implants supporting full overdentures and (2) histomorphometric analysis of the same implants in an animal model, comparing implants with various surface treatments. Methods: (1) Clinical trial: 24 completely edentulous participants (2 groups of N = 12) received 7 implants (one-piece ball-abutment ZC or Ti; maxilla N = 4, mandible N = 3) restored with implant overdentures. Outcomes after 8-years included survival, peri-implant bone levels, soft-tissue responses, and prosthodontic issues. (2) Preclinical trial: 10 New Zealand sheep received 4 implants bilaterally in the femoral condyle: Southern Implants ZC or Ti one-piece implants, identical to the clinical trial, and controls: Southern ITC® two-piece implants with the same surface or Nobel (NBC) anodised (TiUnite™) surface. %Bone-implant contact (%BIC) was measured after 12 weeks of unloaded healing. Results: 8 of 24 participants (33%) of an average age of 75 ± 8 years were recalled; 21% of original participants had died, and 46% could not be contacted. 80.4% of implants survived; excluding palatal sites, 87.5% of Ti and 79% of ZC implants survived. All failed implants were in the maxilla. Three ZC implants had fractured. Bone loss was similar for Ti vs. ZC; pocket depths (p = 0.04) and attachment levels (p = 0.02) were greater for Ti than ZC implants. (1.7 ± 1.6 mm vs. 1.6 ± 1.3 mm). All implants in sheep femurs survived. %BIC was not statistically different for one-piece blasted surface Ti (80 ± 19%) versus ZC (76 ± 20%) or ITC® (75 ± 16 mm); NBC had significantly higher %BIC than ITC (84 ± 17%, p = 0.4). Conclusion: Short-term preclinical results for ZC and Ti one-piece implants showed excellent bone-implant contact in unloaded femoral sites. This differed from the long-term clinical results in older-aged, edentulous participants. While ZC and Ti implants showed equivalent performance, the risks of peri-implantitis and implant loss in older, completely edentulous patients remain a significant factor.
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Jakobsen, Thomas, Søren Kold, Jørgen Baas, Kjeld Søballe, and Ole Rahbek. "Sheep Hip Arthroplasty Model of Failed Implant Osseointegration." Open Orthopaedics Journal 9, no. 1 (November 13, 2015): 525–29. http://dx.doi.org/10.2174/1874325001509010525.
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Early secure stability of an implant is important for long-term survival. We examined whether micromotion of implants consistently would induce bone resorption and formation of a fibrous membrane and thereby prevent osseointegration.One micromotion implant was inserted into one of the medial femoral condyles in ten sheep. The micromotion device consists of an anchor bearing a PMMA implant and a PE plug. During each gait cycle the PE plug will make the PMMA implant axially piston 0.5 mm. After 12 weeks of observation the bone specimens were harvested and a post-mortem control implant was inserted into the contra-lateral medial femoral condyle.Histomorphometrical evaluation showed that the surface on the implant observed for 12 weeks was covered by fibrous tissue. The control implants were covered by lamellar bone. No difference was found with respect to the volume fraction of lamellar bone in a 1 mm zone around the implants.This study indicates that implant micromotion is sufficient to induce bone resorption and formation of a fibrous membrane.
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Messamore, William, Matthew Vopat, Elizabeth Helsper, Andrew Bachinskas, Michelle Nentwig, and Tarun Bhargava. "Short-Term Radiographic Evaluation of a Tri-Tapered Femoral Stem in Direct Anterior Total Hip Arthroplasty." Kansas Journal of Medicine 13, no. 1 (March 20, 2020): 51–55. http://dx.doi.org/10.17161/kjm.v13i1.13528.
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Introduction. Direct anterior approach (DAA) total hip arthroplasty (THA) has become increasingly popular, largely due to utilization of a true internervous and intermuscular plane. However, recent literature has demonstrated an increased rate of femoral implant subsidence with this approach. Hence, different femoral implants, such as the tri-tapered femoral stem, have been developed to facilitate proper component insertion and positioning to prevent this femoral subsidence. The purpose of this study was to evaluate the subsidence rate of a tri-tapered femoral stem implanted utilizing a DAA, and to determine if the proximal femoral bone quality affects the rate of subsidence.
Methods. A retrospective analysis of 155 consecutive primary THAs performed by a single surgeon was conducted. Age, gender, primary diagnosis, and radiographic measurements of each subject were recorded. Radiological evaluations, such as bone quality, femoral canal fill, and implant subsidence, were measured on standardized anteroposterior (AP) and frog-leg lateral radiographs of the hip at 6-week and 6-month postoperative follow-up evaluations.
Results. The average subsidence of femoral stems was 1.18 ± 0.8 mm. There was no statistical difference in the amount of subsidence based on diagnosis or proximal femora quality. The tri-tapered stem design consistently filled the proximal canal with an average of 91.9 ± 4.9% fill. Subsidence was not significantly associated with age, canal flare index (CFI), or experience of the surgeon.
Conclusion. THA utilizing the DAA with a tri-tapered femoral stem can achieve consistent and reliable fit regardless of proximal femoral bone quality.
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Krueger, D. R., K.-P. Guenther, M. C. Deml, and C. Perka. "Mechanical failure of 113 uncemented modular revision femoral components." Bone & Joint Journal 102-B, no. 5 (May 2020): 573–79. http://dx.doi.org/10.1302/0301-620x.102b5.bjj-2019-1333.r2.
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Aims We evaluated a large database with mechanical failure of a single uncemented modular femoral component, used in revision hip arthroplasty, as the end point and compared them to a control group treated with the same implant. Patient- and implant-specific risk factors for implant failure were analyzed. Methods All cases of a fractured uncemented modular revision femoral component from one manufacturer until April 2017 were identified and the total number of implants sold until April 2017 was used to calculate the fracture rate. The manufacturer provided data on patient demographics, time to failure, and implant details for all notified fractured devices. Patient- and implant-specific risk factors were evaluated using a logistic regression model with multiple imputations and compared to data from a previously published reference group, where no fractures had been observed. The results of a retrieval analysis of the fractured implants, performed by the manufacturer, were available for evaluation. Results There were 113 recorded cases with fracture at the modular junction, resulting in a calculated fracture rate of 0.30% (113/37,600). The fracture rate of the implant without signs of improper use was 0.11% (41/37,600). In 79% (89/113) of cases with a failed implant, either a lateralized (high offset) neck segment, an extralong head, or the combination of both were used. Logistic regression analysis revealed male sex, high body mass index (BMI), straight component design, and small neck segments were significant risk factors for failure. Investigation of the implants (76/113) showed at least one sign of improper use in 72 cases. Conclusion Implant failure at the modular junction is associated with patient- and implant-specific risk factors as well as technical errors during implantation. Whenever possible, the use of short and lateralized neck segments should be avoided with this revision system. Implantation instructions and contraindications need to be adhered to and respected. Cite this article: Bone Joint J 2020;102-B(5):573–579.
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Le Guenhennec, Laurent, Eric Goyenvalle, Marco A. Lopez-Heredia, Pierre Weiss, Yves Amouriq, and Pierre Layrolle. "Histomorphometric Evaluation of Bone Response to Different Titanium Implant Surfaces." Key Engineering Materials 361-363 (November 2007): 613–16. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.613.
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Titanium dental implants presenting different blasted surfaces and an OCP coated surfaces have been implanted in the femoral epiphysis of rabbits. A comparable osseointegration has been observed for the titanium implants blasted either with alumina or biphasic calcium phosphates particles whatever the delay of implantation (2 or 8 weeks). A higher bone to implant contact has been observed for the SLA and OCP coated implants as compared to the grit-blasted groups.
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Gustian, H. Soehartono, N. Jujur, A. H. S. Wargadipura, and D. Noviana. "Blood profile of implantation stainless steel 316L local implant material on rat femoral bone." Jurnal Ilmu Ternak dan Veteriner 23, no. 3 (September 20, 2018): 123. http://dx.doi.org/10.14334/jitv.v23i3.1836.
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<p><em><strong></strong></em>This study was aimed to obtain information regarding complete blood count (CBC) profile of post implantation of stainless steel (SS) 316L as an Indonesian local product of non-degradable metal implant. Thirty adult male rat, aged approximately 12 weeks were divided into 3 groups, i.e. control group without implantation, implant group with import SS316L and implant group with Indonesian national local SS316L that developed by Agency for the Assessment and Application of Technology (BPPT). The implant groups were given implants by inserting it between femoral bone and biceps femoris muscle. On the control group, defect was made on bone without inserting an implants material. Examination of the systemic response was done with CBC before and 30 days after implantation. The analysis of red blood cells amount, haemoglobin level, haematocrite value, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), total white blood cell and its differentiation from each group did not show significant differences. In conclusion, stainless steel 316L of import and national local product showed non-negative effects on blood profile.</p>
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Steele, John R., Daniel J. Cunningham, and Samuel B. Adams. "Comparison of Custom 3D Printed Spherical Implants vs Femoral Head Allografts for Tibiotalocalcaneal Arthrodeses." Foot & Ankle Orthopaedics 4, no. 4 (October 1, 2019): 2473011419S0040. http://dx.doi.org/10.1177/2473011419s00407.
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Category: Ankle Arthritis, Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis is a common treatment option for hindfoot arthritis, deformity correction and salvage of failed total ankle replacement. However, union can be difficult to achieve in patients with bulk bone defects. Femoral head allograft is commonly used in the setting of TTC fusion with severe bone loss, but recent studies have reported concerns of arthrodesis rates of 50% or worse and graft collapse in these patients. Retrograde intramedullary nail placement through custom 3D spherical implants is a novel option for these patients. The purpose of this study was to compare fusion rates, graft resorption and complication rates between patients undergoing TTC fusion with 3D sphere implants versus femoral head allografts. Methods: All patients who underwent TTC arthrodesis with an intramedullary nail along with a 3D spherical implant or femoral head allograft by the senior author at a single institution from 2013 to 2017 and who had at least one year of follow-up were included in this study. There were 7 patients who received a femoral head allograft and 8 patients who received a 3D printed sphere. Baseline patient and operative characteristics were collected and compared between the 3D sphere and femoral head allograft groups. The rate of successful fusion of the tibia, calcaneus and talar neck to the 3D sphere or femoral head allograft, as determined by radiographs and CT scan, as well as graft resorption and complications were compared between the groups. Results: The rates of union of the tibia (87.5% vs 71.4%), calcaneus (87.5% vs 71.4%), and talar neck (100% vs 42.9%) were higher in the 3D sphere group than in the femoral head allograft group. The rate of union of the talar neck was significantly higher to the 3D sphere implant than to the femoral head allograft (p=0.016). The number of patients achieving successful fusion of all three articulations was higher in the 3D sphere group (75%) than the femoral head allograft group (42.9%), although not statistically significant (p=0.22). The rate of graft resorption was significantly higher in the femoral head allograft group (57.1%) than the 3D sphere group (0%, p=0.016).There were no differences between the groups in terms of complications. Conclusion: These data demonstrate that the use of a custom 3D-printed sphere implant is safe in patients with severe bone loss undergoing TTC arthrodesis with a retrograde intramedullary nail. The rate of successful fusion of all three tibial, calcaneal and talar neck articulations was higher to the 3D sphere than to the femoral head allograft, although not statistically significant. Union of the talar neck was significantly higher to the 3D sphere implants than it was to the femoral head allograft. Subsidence was significantly higher with the femoral head allograft than the 3D sphere.
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Oltean-Dan, Daniel, Gabriela-Bombonica Dogaru, Elena-Mihaela Jianu, Sorin Riga, Maria Tomoaia-Cotisel, Aurora Mocanu, Lucian Barbu-Tudoran, and Gheorghe Tomoaia. "Biomimetic Composite Coatings for Activation of Titanium Implant Surfaces: Methodological Approach and In Vivo Enhanced Osseointegration." Micromachines 12, no. 11 (October 31, 2021): 1352. http://dx.doi.org/10.3390/mi12111352.
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Innovative nanomaterials are required for the coatings of titanium (Ti) implants to ensure the activation of Ti surfaces for improved osseointegration, enhanced bone fracture healing and bone regeneration. This paper presents a systematic investigation of biomimetic composite (BC) coatings on Ti implant surfaces in a rat model of a diaphyseal femoral fracture. Methodological approaches of surface modification of the Ti implants via the usual joining methods (e.g., grit blasting and acid etching) and advanced physicochemical coating via a self-assembled dip-coating method were used. The biomimetic procedure used multi-substituted hydroxyapatite (ms-HAP) HAP-1.5 wt% Mg-0.2 wt% Zn-0.2 wt% Si nanoparticles (NPs), which were functionalized using collagen type 1 molecules (COL), resulting in ms-HAP/COL (core/shell) NPs that were embedded into a polylactic acid (PLA) matrix and finally covered with COL layers, obtaining the ms-HAP/COL@PLA/COL composite. To assess the osseointegration issue, first, the thickness, surface morphology and roughness of the BC coating on the Ti implants were determined using AFM and SEM. The BC-coated Ti implants and uncoated Ti implants were then used in Wistar albino rats with a diaphyseal femoral fracture, both in the absence and the presence of high-frequency pulsed electromagnetic shortwave (HF-PESW) stimulation. This study was performed using a bone marker serum concentration and histological and computer tomography (micro-CT) analysis at 2 and 8 weeks after surgical implantation. The implant osseointegration was evaluated through the bone–implant contact (BIC). The bone–implant interface was investigated using FE-SEM images and EDX spectra of the retrieved surgical implants at 8 weeks in the four animal groups. The obtained results showed significantly higher bone–implants contact and bone volume per tissue volume, as well as a greater amount of newly formed bone, in the BC-coated Ti implants than in the uncoated Ti implants. Direct bone–implant contact was also confirmed via histological examination. The results of this study confirmed that these biomimetic composite coatings on Ti implants were essential for a significant enhancement of osseointegration of BC-coated Ti implants and bone regeneration. This research provides a novel strategy for the treatment of bone fractures with possible orthopedic applications.
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Simões, J. A. O., M. Taylor, A. T. Marques, and G. Jeronimidis. "Preliminary investigation of a novel controlled stiffness proximal femoral prosthesis." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 212, no. 3 (March 1, 1998): 165–75. http://dx.doi.org/10.1243/0954411981533944.
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Previous studies have suggested that a controlled stiffness prosthesis is required to address the conflicting requirements of minimizing stress shielding and micromotion. The design for a controlled stiffness prosthesis is proposed and a preliminary analytical investigation performed to assess its predicted performance before fabrication of a prototype component. The novel prosthesis consisted of a cobalt-chrome core and a flexible composite outer layer. Varying the composite layer thickness allowed the prosthesis stiffness to be controlled. Three variants of the controlled stiffness prosthesis were critically assessed using the finite element method and their predicted performance compared with those of conventional prosthesis designs. The potential for stress shielding was assessed by examining the periosteal strain energy and the potential for migration assessed by examining the endosteal minimum principal cancellous bone stresses. Both the conventional and controlled stiffness implants performed poorly as press-fit prostheses. All the press-fit prostheses generated high cancellous bone stresses, suggesting that excessive migration of these implants would be likely. The controlled stiffness implants performed better than the conventional implants when bonded to the surrounding bone. Although the controlled stiffness implants did not eliminate stress shielding of the calcar, they produced higher strain energies than the conventional designs. The findings of this study are that osseointegrated controlled stiffness implants may perform better than current osseointegrated cementless prostheses and therefore it is worth while progressing to the next stage, of prototyping an implant.
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Valverde-Mordt, C., and D. Valverde-Belda. "Conservative femoral implants. Short stems." Revista Española de Cirugía Ortopédica y Traumatología (English Edition) 56, no. 1 (January 2012): 72–79. http://dx.doi.org/10.1016/j.recote.2011.08.003.
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Yu, Xiao, Peng-ze Rong, Qing-jiang Pang, Xian-jun Chen, Lin Shi, and Cheng-hao Wang. "The Effect on the Fracture Healing following Femoral Neck Shortening after Osteoporotic Femoral Neck Fracture Treated with Internal Fixation: Finite Element Analysis." BioMed Research International 2021 (August 4, 2021): 1–7. http://dx.doi.org/10.1155/2021/3490881.
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Objective. To evaluate the stress status of fracture site caused by femoral neck shortening and to analyze the stress of fracture site and the implants from the finite element point of view. Methods. CT scan data of hip of a normal adult female were collected. Three-dimensional reconstruction MICs and related module function simulation was used to establish the postoperative shortening model of femoral neck fracture with Pauwels angle > 50 ° , which was treated with cannulated screws. The models were divided into four groups: normal femoral neck, shortening in 2.5 mm, shortening in 7.5 mm, and shortening in 12.5 mm. The finite element analysis software msc.nastran2012 was used, and the data of maximum stress and stress nephogram of fracture site and implants were carried out. Results. From normal femoral neck to shortening in 12.5 mm of the femoral neck, the maximum tensile stress increased gradually in the fracture site above the cannulated screws while compressive stress decreased gradually in the fracture site below the cannulated screws, and the maximum stress of the cannulated screws increased gradually with obvious stress concentration at the screw holes in the fracture site, and the peak value of stress concentration was about 179 MPa. Conclusion. The biomechanical environment of the fracture site changed by femoral neck shortening. With the increasing of femoral neck shortening, the stress of the fracture site and implants would be uneven; then, the stability of fracture site would become worse, and the possibility of implant sliding or even breakage would be increased.
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de Ruiter, Lennert, Raelene M. Cowie, Louise M. Jennings, Adam Briscoe, Dennis Janssen, and Nico Verdonschot. "The Effects of Cyclic Loading and Motion on the Implant–Cement Interface and Cement Mantle of PEEK and Cobalt–Chromium Femoral Total Knee Arthroplasty Implants: A Preliminary Study." Materials 13, no. 15 (July 26, 2020): 3323. http://dx.doi.org/10.3390/ma13153323.
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This study investigated the fixation of a cemented PEEK femoral TKA component. PEEK and CoCr implants were subjected to a walking gait cycle for 10 million cycles (MC), 100,000 cycles or 0 cycles (unloaded control). A method was developed to assess the fixation at the cement–implant interface, which exposed the implants to a fluorescent penetrant dye solution. The lateral condyles of the implants were then sectioned and viewed under fluorescence to investigate bonding at the cement–implant interface and cracking of the cement mantle. When tested for 100,000 cycles, debonding of the cement–implant interface occurred in both PEEK (61%) and CoCr (13%) implants. When the duration of testing was extended (10 MC), the percentage debonding was further increased for both materials to 88% and 61% for PEEK and CoCr, respectively. The unloaded PEEK specimens were 79% debonded, which suggests that, when PEEK femoral components are cemented, complete bonding may never occur. Analysis of cracks in the cement mantle showed an absence of full-thickness cracks in the unloaded control group. For the 100,000-cycle samples, on average, 1.3 and 0.7 cracks were observed for PEEK and CoCr specimens, respectively. After 10 MC, these increased to 24 for PEEK and 19 for CoCr. This was a preliminary study with a limited number of samples investigated, but shows that, after 10 MC under a walking gait, substantial debonding was visible for both PEEK and CoCr implants at the cement–implant interface and no significant difference in the number of cement cracks was found between the two materials.
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Siddiqi, A., W. J. Duncan, R. K. De Silva, and S. Zafar. "One-Piece Zirconia Ceramic versus Titanium Implants in the Jaw and Femur of a Sheep Model: A Pilot Study." BioMed Research International 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/6792972.
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Reports have documented titanium (Ti) hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr) ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC) of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control) and one Zr (test) implant were placed in the mandible, and one of each implant (Ti and Zr) was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur (85.5%, versus 78.9%) (p=0.002). Zirconia implants in the mandible showed comparable %BIC to titanium implants (72.2%, versus 60.3%) (p=0.087). High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.
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Crawford, H. V., P. S. Unwin, and P. S. Walker. "The CADCAM Contribution to Customized Orthopaedic Implants." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 206, no. 1 (March 1992): 43–46. http://dx.doi.org/10.1243/pime_proc_1992_206_260_02.
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CADCAM (computer aided design/manufacture) production methods are often associated with mass production; working in the medical field at the Department of Biomedical Engineering, the requirement is for one-off, individualized implants. Using a knowledge-based system, implant designs are produced from X-ray data. Assembly from modular components has greatly reduced the production time of implants for bone tumour cases. CADCAM techniques are also used in the production of custom-made hip replacements using digitized data gathered from radiographs. Femoral canal shape is calculated and the optimal implant designed and manufactured from titanium alloy on the Department's CNC (computer numerically controlled) machines.
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Nickelsen, T. N., M. Erenbjerg, J. B. Retpen, and S. Solgaard. "Femoral Revision with Impaction Allografting and an Uncemented Femoral Component." HIP International 18, no. 4 (October 2008): 278–85. http://dx.doi.org/10.1177/112070000801800403.
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A technique for uncemented revision of the femoral component which combines impaction allografting and the use of a long-stemmed proximally coated titanium prostheses (Bimetric®, Biomet Inc.) is described. The results after a mean follow-up of 112 months are reported. From 1991 to 1995 femoral component revision for aseptic loosening was performed on 100 hips. In 14 cases (14%) an intraoperative fracture occurred and 7 patients (7%) had other postoperative complications. Seventeen patients (17%) required further revision, 10 because of aseptic loosening. Of 50 surviving patients with retained implants 88% had no pain, 10% had slight pain and only 2% had severe pain. Thirty-eight patients had radiographic signs of remodelling of the graft and/or cortical repair. In cases with a successful outcome, the results have been encouraging in relation to clinical performance, regeneration of bone and implant survival.
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Shalabi, Manal M., Johannes G. C. Wolke, Anja J. E. de Ruijter, and John A. Jansen. "A Mechanical Evaluation of Implants Placed With Different Surgical Techniques Into the Trabecular Bone of Goats." Journal of Oral Implantology 33, no. 2 (April 1, 2007): 51–58. http://dx.doi.org/10.1563/0-827.1.
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Abstract The aim of the study was to assess the effects of surgical technique and implant surface roughness on implant fixation. A total of 48 screw implants with machined or etched surface topographies were placed into the femoral condyles of goats. The implant sites were prepared by a conventional technique, by undersized preparation, or by the osteotome technique. Bone tissue responses were evaluated after 12 weeks of healing by removal torque testing and histologic analysis using scanning electron microscope. The cumulative removal torque value of the etched implants placed with the undersized technique (98 ± 29 Ncm) was higher (50 ± 35 Ncm) to a level of statistical significance than machined surface implants placed by the osteotome technique. Scanning electron microscope evaluation indicated that all implants showed interfacial bone contact. The torque test resulted in fracture at the bone-implant interface for all experimental conditions. Installation of etched implants using an undersized preparation of the implant bed resulted in superior bonding strength with the surrounding bone at 12 weeks after surgery. Evidently, the undersized preparation technique improved the early fixation of oral implants in this study.
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Murphy, Susan, Jelena Jovanovik, Russell Tucker, Noel Fitzpatrick, and Pádraig Egan. "Treatment of Osteochondrosis Dissecans of the Canine Stifle Using Synthetic Osteochondral Resurfacing." Veterinary and Comparative Orthopaedics and Traumatology 31, no. 02 (February 2018): 144–52. http://dx.doi.org/10.3415/vcot-17-02-0035.
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Objective This article aimed to describe the use and evolution of a synthetic osteochondral resurfacing (SOR) implant in the treatment of osteochondrosis dissecans (OCD) of the femoral condyle and to report the clinical, radiographic, computed tomography and magnetic resonance imaging outcomes of this technique. Methods Medical records of dogs that were treated with first-generation (G1) and second-generation (G2) SOR at a single institute were reviewed. Surgical reports and clinical examinations as well as the preoperative, postoperative, and follow-up radiographs, computed tomographic images and magnetic resonance imaging images were reviewed. Results Fourteen stifles (nine dogs) were included in the study. G1-SOR implants were employed in six stifles of four dogs and G2-SOR implants in eight stifles of five dogs. Osteochondrosis dissecans of the medial femoral condyle was confirmed as the sole pathology in all dogs treated with G1-SOR. Only one of eight OCD lesions was located on the medial condyle in the G2-SOR group with the remaining seven lesions affecting the lateral femoral condyle. At 12 weeks, 13 of 14 stifles displayed implant stability, with no subchondral bone changes or evidence of lucency around any implant. Eight of nine dogs achieved a good-excellent clinical outcome. Complications included one minor surgical site infection and one infective arthritis which required implant removal. Clinical Significance In this cohort of dogs, both G1-SOR and G2-SOR were successful and repeatable surgical procedures for dogs with OCD of the femoral condyle.
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Choi, Ik-sun, Seung-Min Na, Jong-Keun Seon, and Eun-Kyoo Song. "Kinematic Analysis of Total Knee Arthroplasty using Verasense: Genesis-II prosthesis versus Anthem prosthesis." Orthopaedic Journal of Sports Medicine 8, no. 5_suppl5 (May 1, 2020): 2325967120S0010. http://dx.doi.org/10.1177/2325967120s00107.
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Purpose The purpose of this study was to elucidate kinematic change according to the implant’s specific femoral rotation by using orthosensor (Verasense) implant with three degrees external rotation of femoral rotation rebuilt (Genesis-II) and traditional TKA implant without rebuilt of the femoral rotation (Anthem). Methods Twenty-eight patients (34 knees) underwent TKA using Anthem (Smith &Nephew, Memphis, TN, USA) and 16 patients (22 knees) underwent TKA using Genesis-II (Smith & Nephew, Memphis, TN, USA). Patients were followed up for at least 1 year. Mean age of patients was 71.1 years (range, 60 to 80 years) at the time of surgery. After implantation of femur and tibial components, we applied Verasense, the orthosensor system, to evaluate femoral rollback of the new artificial joint. Femoral rollback was analyzed using digitized screenshot function of Verasense. Results Overall femoral tracking proportion regardless of implants was significantly higher on the medial compartment compared to that on the lateral compartment (13.3 ±8.4% vs. 6.3 ± 5.0%, p < 0.001). Regarding femoral tracking according to each compartment, Genesis-II and Anthem showed 12.1 ± 8.2% and 14.2 ± 8.6% ( p = 0.371) on the medial compartment and 8.0 ± 5.8% and 5.2 ± 4.2% ( p = 0.059) on the lateral compartment, respectively. Conclusion Our study showed reverse femoral roll-back movement with higher tracking distance on the lateral compartment during TKA. Genesis-II TKA system with femoral component 3-degree rebuilt showed less roll-back difference between medial and lateral compartments compared to traditional TKA system. Fortunately, both TKA systems had excellent short-term clinical outcomes without having significant difference between the two. With longer follow-up and larger cohort, the advantage and effectiveness of femoral component rotation can be elucidated in the future.
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ASGARI, S. A., A. M. HAMOUDA, S. B. MANSOR, E. MAHDI, R. WIRZA, and H. SINGH. "NATURAL FIBER REINFORCED COMPOSITES FOR FEMORAL COMPONENT OF TOTAL HIP ARTHROPLASTY." Journal of Mechanics in Medicine and Biology 05, no. 03 (September 2005): 443–54. http://dx.doi.org/10.1142/s0219519405001576.
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This paper describes a theoretical approach to compare two types of fiber reinforced composite materials for femoral component of hip implants. The natural fiber reinforced composite implant is compared with carbon fiber reinforced composite and the results are evaluated against the control solution of a metallic implant made of titanium alloy. With identical geometry and loading condition, the composite implants assumed lower stresses, thus induced more loads to the bone and consequently reduced the risk of stress shielding, whilst the natural fiber reinforced composite showed promising result compared with carbon fibers. However, natural fibers, as well as carbon fibers, lack the power to improve interface debonding due to excessive loads in interface. Nevertheless, natural fiber reinforced composite could be an appropriate alternative given its capability of tailoring and achieving the optimal fiber orientation and robust design.
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Velasco-Ortega, Eugenio, Iván Ortiz-Garcia, Alvaro Jiménez-Guerra, Enrique Núñez-Márquez, Jesús Moreno-Muñoz, José Luis Rondón-Romero, Daniel Cabanillas-Balsera, Javier Gil, Fernando Muñoz-Guzón, and Loreto Monsalve-Guil. "Osseointegration of Sandblasted and Acid-Etched Implant Surfaces. A Histological and Histomorphometric Study in the Rabbit." International Journal of Molecular Sciences 22, no. 16 (August 7, 2021): 8507. http://dx.doi.org/10.3390/ijms22168507.
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Titanium surface is an important factor in achieving osseointegration during the early wound healing of dental implants in alveolar bone. The purpose of this study was to evaluate sandblasted-etched surface implants to investigate the osseointegration. In the present study, we used two different types of sandblasted-etched surface implants, an SLA™ surface and a Nanoblast Plus™ surface. Roughness and chemical composition were evaluated by a white light interferometer microscope and X-ray photoelectron spectroscopy, respectively. The SLA™ surface exhibited the higher values (Ra 3.05 μm) of rugosity compared to the Nanoblast Plus™ surface (Ra 1.78 μm). Both types of implants were inserted in the femoral condyles of ten New Zealand white rabbits. After 12 weeks, histological and histomorphometric analysis was performed. All the implants were osseointegrated and no signs of infection were observed. Histomorphometric analysis revealed that the bone–implant contact % (BIC) ratio was similar around the SLA™ implants (63.74 ± 13.61) than around the Nanoblast Plus™ implants (62.83 ± 9.91). Both implant surfaces demonstrated a favorable bone response, confirming the relevance of the sandblasted-etched surface on implant osseointegration.
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Lee, Sun Young, Dong Jun Yang, Shinil Yeo, Hyun Wook An, Sung Jun Kim, Won Mi Choi, and Kwang Bum Park. "Effect of XPEED® on Ti Implants with Deep Threads." Key Engineering Materials 493-494 (October 2011): 442–46. http://dx.doi.org/10.4028/www.scientific.net/kem.493-494.442.
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Calcium-incorporated titanium (Ti) recently reported a large degree of effectiveness in many in vitro and in vivo studies. The implants with the deeper thread provide the higher surface area and will have an advantage in soft bone. We used the Ti implants with deep threads and investigated osseintegration of the implants with resorbable blast media (RBM) surfaces produced by grit-blasting or XPEED surfaces by coating of the nanostrucutred calcium.The Ti implants with deep threads had a thread diameter of 4.0 mm, a length of 5.0 mm and a thread depth of 1.0 mm. The Ti implants with calcium-incorporated surfaces (XPEED surfaces) were hydrothermally prepared from the Ti implants with RBM surfaces in alkaline calcium containing solution. The surface characteristics were evaluated by using scanning electron microscope (SEM) and surface roughness measuring system. Thirty-implants with RBM surfaces and thirty-implants with XPEED surfaces were randomly placed in the proximal tibiae and in the femoral condyles of ten New Zealand White rabbits. The osseointegration was evaluated by removal torque test in the proximal tibiae and histomorphometric analysis in the femoral condyles. The Ti implants with XPEED surfaces showed a similar surface morphology and surface roughness to those of the Ti implants with RBM surfaces. The mean removal torque of the Ti implants with XPEED surfaces was higher than the Ti implants with RBM surfaces (p < 0.05). The percentage of bone-to-implant contact (BIC %) were increased for the Ti implants with XPEED surfaces compared with the Ti implants with RBM surfaces (p < 0.05).The Ti implants with XPEED surfaces significantly enhanced the removal torque and the BIC %. The Ti implants with XPEED surfaces may be shorten healing time of bone by improving osseointegration of Ti implants with deep threads.
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Guthrie, James, and Noel Fitzpatrick. "Single-Stage Revision of an Infected Total Hip Replacement Using Antibiotic-Impregnated Bioabsorbable Beads in a Canine Patient." VCOT Open 02, no. 01 (January 2019): e5-e12. http://dx.doi.org/10.1055/s-0038-1677523.
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AbstractThis report describes a technique and the outcome following surgical revision of a periprosthetic infected total hip replacement (THR) in a single-stage procedure with the use of antibiotic-impregnated bioabsorbable beads. A 6-year-old German Shepherd dog underwent THR 16 months previously, which subsequently became infected. The contaminated femoral and acetabular prostheses were explanted. A femoral window was used to remove the stem and cement. The endosteal surfaces of the femur and acetabulum were reamed to remove periprosthetic tissues. The femoral window was replaced and secured in position with multiple cerclage wires. A 3.5-mm locking plate was applied to the lateral aspect of the femur to prevent fracture of the proximal femoral metaphysis and trochanter. Bioabsorbable beads of calcium sulphate, impregnated with vancomycin and gentamicin, were impacted into the femoral canal followed by an uncemented femoral stem. An uncemented acetabular implant was impacted and additional antibiotic beads placed in the vicinity prior to closure. There has been no evidence of reinfection 5 years postoperatively. Analgesic and antibacterial drugs were not required during this follow-up period; activity is unrestricted with neither lameness nor pain present. Simultaneous revision of both femoral and acetabular periprosthetic infected THR implants was successfully achieved in this patient via a single-stage procedure using uncemented implants and antibiotic-impregnated bioabsorbable beads.
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Pokharel, Bishnu, Ashok Raj Pant, Pashupati Chaudhary, and Guru Prasad Khanal. "Morphometric Parameters of the Proximal Femur in Nepalese Population: A Cross-sectional Study." Journal of BP Koirala Institute of Health Sciences 3, no. 2 (December 31, 2020): 8–12. http://dx.doi.org/10.3126/jbpkihs.v3i2.36085.
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Background: Most of the proximal femur fractures are managed surgically by internal fiation with a variety of implants. Improperly designed or ill-fited implant may lead to a failure of fiation, breakage of implant and nonunion, thus increasing the morbidity and the cost of treatment. This study was conducted to evaluate the radiographic morphometry of the proximal femur which may be helpful in designing the implants for the Nepalese population.
Methods: In this cross-sectional study, 84 patients aged 18 years and above with traumatic unilateral hip fracture were enrolled. Anthropometric measurements were recorded. The postoperative check X-ray in the antero-posterior view of the pelvis and bilateral hip were assessed. Various morphometric parameters of the proximal femur were measured and recorded in the radiograph of the unaffcted limb using a digital caliper.
Results: Out of 84 patients, 47 were male. The mean ± SD femoral neck width, femoral neck length, femoral axis length, cervico-diaphyseal angle, acetabular tear-drop distance, and great trochanter-pubic symphysis distance were 36.10 ± 5.67 mm, 28.29 ± 4.18 mm, 104.51 ± 9.56 mm, 130.35 ± 8.67°, 32.56 ± 11.05 mm, and 163.07 ± 10.71 mm respectively. The femoral neck width was found to be signifiantly larger in males (39.08 ± 3.06 mm) than in females (32.32 ± 5.99 mm, p < 0.001).
Conclusion: This study determined the radiographic measurement of the proximal femur and found that the femoral neck width of the males was larger than that of the females.
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Jiang, Gang-Qiang, Ya-Di Zhang, and Yun-Qiang Zhuang. "Removal of broken reamer stuck into femoral shaft in implanting PFNA: a case report." SICOT-J 4 (2018): 31. http://dx.doi.org/10.1051/sicotj/2018024.
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Femoral intertrochanteric fracture is very common in elderly population. The usual treatment for these patients is intra-extramedullary fixation. In normal situations, expand medullary cavity is needed, in order to implant various intramedullary implants. On rare occasion, which will in turn lead to the reamer is stuck into the medullary cavity of femoral shaft. Open or closed technique for moving of the broken nails had been reported before. We firstly report a novel technique by using handy tool which included in orthopaedic instrument set to remove the broken reamer stuck into femoral cavity when implanting a PFNA.
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Ajami, Elnaz, Cong Fu, Hai Bo Wen, Jeffrey Bassett, Sun Jin Park, and Marie Pollard. "Early Bone Healing on Hydroxyapatite-Coated and Chemically-Modified Hydrophilic Implant Surfaces in an Ovine Model." International Journal of Molecular Sciences 22, no. 17 (August 28, 2021): 9361. http://dx.doi.org/10.3390/ijms22179361.
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Implant topography affects early peri-implant bone healing by changing the osteoconduction rate in the surrounding biological environment. Implant surfaces have been designed to promote faster and stronger bone formation for rapid and stable prosthesis loading. Early peri-implant bone healing has been observed with a sandblasted, acid-etched implant that was chemically modified to be hydrophilic (cmSLA). The present study investigates whether early peri-implant bone healing extends to a rough surface implant with a high crystalline hydroxyapatite surface (TSV MP-1 HA). Three implants were randomly placed in porous trabecular bone within both medial femoral condyles of 10 sheep. Early peri-implant bone stability was measured at 3- and 6-weeks healing time following implant insertion. Results indicated a similar implant stability quotient between the implants at insertion and over time. The significant increase over time of reverse torque values with respect to insertion torque (p < 0.001) did not differ between the implants. However, the bone-to-implant contact of TSV MP-1 HA was significantly higher than that of cmSLA implants at 6 weeks (p < 0.01). These data validate previous findings of a hydrophilic implant surface and extend the observation of early osseointegration to a rough surface implant in porous trabecular bone.
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Shubnyakov, I. I., A. Riahi, M. I. Shubnyakov, A. O. Denisov, I. E. Khujanazarov, and R. M. Tikhilov. "Cementless Hip Implants: History and Current Status of the Issue." Traumatology and Orthopedics of Russia 26, no. 2 (July 9, 2020): 160–79. http://dx.doi.org/10.21823/2311-2905-2020-26-2-160-179.
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Background. Total hip arthroplasty is an effective type of surgery with excellent survival rates of modern implants. From the very beginning of the widespread introduction of total hip arthroplasty, the cement technique of components fixing prevailed. However, many researchers associated the development of osteolysis and the following loosening with the reaction to cement. The subsequent studies clarified the situation regarding the nature of osteolysis, but there remained the problem of insufficient stability of the cemented stems to withstand the penetration of polyethylene wear particles into the distal part of the stem with the development of loosening. An ideal endoprosthesis should ensure the normal hip biomechanics, joint painless functioning and improve the quality of life of the patient without the need for revision. The optimal results of cementless femoral stems functioning depend on the achievement of initial stability, osseointegration and equable transmission of tension onto the femur. There are many factors that influence osseointegration processes and the subsequent behavior of the implant. Understanding these factors is the key to choosing the optimal implant for a particular patient, taking into account the anatomical features of the femur.The purpose of this article is to discuss upon the literature review the application of cementless femoral components, the possible causes of failure and its prevention from the point of view of the evidence-based practice.Materials. The search was conducted in the PubMed, eLIBRARY databases and through the Web of Knowledge. Survival rates and prevalence of various implants in the structure of primary arthroplasty were estimated on the basis of annual reports of a number of national registries, as well as the hip arthroplasty registry of the Vreden National Medical Research Center of Traumatology and Orthopedics. Among the factors discussed are the properties of the components material, the form of the implants, surface properties, and the influence of the anatomical features of the femur. Additionally, the most used types of cementless femoral components were assessed.Conclusion. Cementless femoral components demonstrated the excellent long-term survival and functional results. The currently prevailing type of the prosthesis intimate attachment to the bone is the biological fixation, especially in groups of young patients. Future studies of cementless implants should necessarily take into account the patient’s age, level of activity, type of bone canal, the presence of deformities, and the friction pair used. This will make it possible to draw clearer conclusions in what clinical situation it is advisable to use the femoral components of a particular design.
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Kibble, Kendra, Sarah C. Peck, Harsh R. Parikh, Ilexa Flagstad, Tiffany Gorman, A. Bandele Okelana, and Brian P. Cunningham. "Geriatric Femoral Neck Fractures: Hemiarthroplasty Implant Trends Across a Health System From 2006 to 2018." Geriatric Orthopaedic Surgery & Rehabilitation 11 (January 1, 2020): 215145932092737. http://dx.doi.org/10.1177/2151459320927378.
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Introduction: Hemiarthroplasty is increasingly used for the treatment of geriatric femoral neck fractures in an effort to optimize value-based care. The current American Association of Orthopaedic Surgeons (AAOS) guidelines released in 2014 for the treatment of geriatric hip fractures recommend the utilization of monopolar cemented constructs. The purpose of this study was to evaluate hip hemiarthroplasty implant cost variability and implant selection trends from 2006 to 2018. Materials and Methods: A retrospective review of 940 geriatric hip fractures treated with hemiarthroplasty was conducted across 3 institutions from 2006 to 2018. Variables examined were construct type, surgeon, operative time, patient mortality, and implant cost. Statistical analysis consisted of multigroup comparative tests and multiple linear regression analyses to evaluate correlative measures. Results: The study population was 85.0 ± 7.9 years of age with a body mass index of 24.0 ± 5.5. A total of 33 (3.5%) patients were deceased at the 90-day postoperative mark and 45 (4.8%) patients at the 1-year mark. There was no statistical difference in terms of mortality between the 4 implant cohorts at the 90-day mark ( P = .56) and 1-year mark ( P = .24). The bipolar press-fit construct was the most expensive, US$3900.61 ± US$2607.54, and the monopolar cemented construct was the least expensive, US$2618.68 ± US$1834.16. The mean operative time was 6 minutes greater for press-fit implants, 93.6 ± 32.0, than cemented implants, 87.1 ± 33.6 ( P = .02). The use of monopolar cemented implants increased from 12.1% to 83.3%, while bipolar press-fit decreased from 57.6% to 4.6% from 2013 to 2018. Discussion: The use of a bipolar and/or press-fit implant significantly increases construct cost despite little evidence in the literature of improved outcomes. Contrary to previous research, cemented implants do not increase the operative time. Conclusions: Encouragingly, selection of the most cost-conscience implant, monopolar cemented, has been increasing since 2014, which may reflect the influence of current AAOS guidelines. Level of Evidence: Diagnostic Level III.
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Gamero, V., J. Valdivia, E. Davila, and M. Cerrolaza. "INFLUENCE OF THE GEOMETRY OF THE ATTACHING PEGS OF THE FEMORAL COMPONENT OF A KNEE PROSTHESIS." Biomedical Engineering: Applications, Basis and Communications 28, no. 03 (June 2016): 1650017. http://dx.doi.org/10.4015/s1016237216500174.
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Several factors such as instability, misalignment, mechanical fractures and poor quality of bone are some factors that strongly influence the deterioration of knee implants. After a total knee replacement (TKR), proximal tibial bone suffers a resorption due to stress-shielding caused by the implant. The formation of weakening bone zones and loss of bone is one of the most clinical concerns. Then, the study, modification and improving of the simulation methods to analyze implants is a subject of the most concern. Thus, this work is focused in the analyses of the influence of the geometry and inclination of the attaching pegs in the femoral component of knee implants. The aim is to evaluate the geometry of the implant stem to improve the stresses distribution and to increase the implant lifespan. Stresses distribution at the attaching pegs of the femoral component, by considering several combinations of diameters, lengths and inclinations, have been analyzed using finite element analysis (FEA). The analysis was conducted for the [Formula: see text][Formula: see text]mm, L [Formula: see text] 13 mm and [Formula: see text] [Formula: see text] 0[Formula: see text], in three different positions of the gait cycle. The variation of the geometry of the attaching pegs generated changes in the stresses distribution in bone. As the diameter increases, the stresses decrease in the femur. The medial areas of the implant appear to be the most likely regions to show bone resorption.
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Prudhon, Jean Louis. "Dual-Mobility Cup and Cemented Femoral Component: 6 Year Follow-Up Results." HIP International 21, no. 6 (November 2011): 713–17. http://dx.doi.org/10.5301/hip.2011.8846.
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Use of a dual-mobility acetabular cup is associated with a lower risk of dislocation compared with conventional hip implants. The seleXys® DS acetabular cup combines the advantages of Charnley low-friction arthroplasty with those of dual mobility. We performed a non-randomised, prospective study of patients receiving primary hip arthroplasty, including an uncemented seleXys® DS dual-mobility acetabular cup with hydroxyapatite coating (Mathys AG, Bettlach, Switzerland) and a cemented femoral component (Stallion femoral stem Groupe Lepine, Lyon, France). The objective of the study was to evaluate longevity of the implant and the risk of dislocation. All operations were performed by a single surgeon using a posterior approach, with patients lying in the lateral decubitus position. The stem had a modular head diameter of 22.2 mm and was cemented in all patients. A total of 53 patients were studied, and the median duration of follow-up was 78.9 months. Implant survival 6 years after surgery was 98.4% (n=47; 95% CI: 89.3–99.8). There was one revision for sepsis 29 months after surgery, and one dislocation. The results of this study appear to demonstrate excellent implant survival and a low rate of dislocation using the chosen implants.
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Scola, Alexander, Florian Gebhard, Christoph Dehner, and Götz Röderer. "The PFNA® Augmented in Revision Surgery of Proximal Femur Fractures." Open Orthopaedics Journal 8, no. 1 (July 11, 2014): 232–36. http://dx.doi.org/10.2174/1874325001408010232.
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Objectives: Modern implants for proximal femur fracture treatment have clearly improved clinical results. However, complications, including cut-out and loss of reduction, requiring revision surgery still occur. A major challenge in these cases is a loss of bone stock due to the existing implant, which is usually exacerbated by osteoporosis. A potential solution is the augmentation of implants, for example, of the femoral neck blade using bone cement. Materials and Methods: Ten patients (five loosening of femoral neck implant, two pseudarthrosis, two implant failures and one acute fracture) were included. The initial hardware was removed and a PFNA augmented was implanted. The perforated femoral neck blade was augmented using polymethyl methacrylate cement. Clinical and radiological follow-up was performed at a mean of 5.4 months (SD ±4.34). The main outcome parameters were fracture healing and implant-related complications. Results: Technical handling was uneventful in all cases. No cement leakage into the joint occurred in any of the cases. The mean amount of cement injected was 5.3 ml. The fracture healed during follow-up in all cases except two patients who died from causes unrelated to the procedure and prior to complete consolidation. Problem-free elective hardware removal of the PFNA augmented was performed in two cases. Discussion: The PFNA augmented is a potential implant for joint-preserving revision surgery in proximal femur fractures. The augmentation improves implant anchorage in the impaired bone stock. In this preliminary series, no negative biological side effects of the cement (i.e. osteonecrosis) were observed.
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Britton, John R., and Patrick J. Prendergast. "Preclinical Testing of Femoral Hip Components: An Experimental Investigation With Four Prostheses." Journal of Biomechanical Engineering 127, no. 5 (April 18, 2005): 872–80. http://dx.doi.org/10.1115/1.1992531.
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Existing standards for the preclinical testing of femoral hip implants have been successful in the objective of guaranteeing the implant’s fatigue strength. There is a need for an experimental test which could ensure prostheses were not susceptible to aseptic loosening. In this study we measure the relative movement between the prosthesis and the bone of four different cemented femoral component designs in in vitro tests. The aim is to determine if differences can be distinguished and whether the differences correlate with clinical performance. The four designs are the Charnley (DePuy International Ltd., UK), the Exeter (Stryker Osteonics Howmedica Corp., USA), the Lubinus SPII (Waldemar-Link GmbH, Germany), and the Müller Curved (JRI Ltd, UK). Five tests were carried out for each femoral component type, giving a total of 20 tests, and their permanent relative displacement (termed migration) and recoverable (i.e., elastic) relative displacement (termed inducible displacement) monitored over one million loading cycles. Considerable variation occurred in the tests. Nonetheless, most femoral components migrated medially, posteriorly, and distally. Most also rotated into varus. Translations of the Charnley (64microns) and Lubinus (67microns) implants were less than the Müller (72microns) and Exeter (94microns) implants, but this difference is not statistically significant. Most of the femoral components had rapid early migration followed by slower steady-state migration. With regard to the steady state inducible displacements of the prostheses, those of the Charnley, Exeter, and Lubinus decreased or were stable with respect to time, whilst those of the Müller typically increased with respect to time. It is concluded that migration is not a suitable basis for in vitro comparison of prosthesis designs. However, inducible displacement trends provide a clinically comparable performance ranking.