Academic literature on the topic 'Mechanical lateral distal femoral angle'
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Journal articles on the topic "Mechanical lateral distal femoral angle"
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Lusetti, Filippo, Andrea Bonardi, Chadi Eid, Anna De Bellesini, and Filippo Maria Martini. "Pelvic limb alignment measured by computed tomography in purebred English Bulldogs with medial patellar luxation." Veterinary and Comparative Orthopaedics and Traumatology 30, no. 03 (2017): 200–208. http://dx.doi.org/10.3415/vcot-16-07-0116.
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SummaryObjectives: The aim of the study was to describe the differences in pelvic limb alignment between healthy purebred English Bulldogs and those with medial patellar luxation through the measurement of femoral and tibial angles on computed tomography images in multiplanar reconstruction modality (MPRCT).Methods: Twenty-one purebred English Bulldogs were included and divided into two groups: one including healthy dogs (15 limbs) and the other including those with medial patellar luxation (24 limbs). Three different observers used MPR-CT to measure the following angles: anatomical lateral proximal femoral angle (aLPFA), anatomical lateral distal femoral angle (aLDFA), mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle of inclination of the femoral neck (AI), angle of anteversion (AA), mechanical medial proximal tibial angle (mMPTA), mechanical medial distal tibial angle (mMDTA), mechanical caudal distal tibial angle (mCdDTA), mechanical caudal proximal tibial angle (mCdPTA), and the tibial torsion angle (TTA). A Mann-Whitney U test was used to compare each variable in both groups.Results: The values for aLDFA and mLDFA in the medial patellar luxation population were significantly increased compared to healthy subjects (p <0.05). No significant differences were observed for the other variables.Clinical significance: In our population, an increased distal femoral varus was associated with medial patellar luxation. Our results could be useful to determine whether or not angular deformity of the femur is present and help determine the degree of correction necessary to restore alignment.ORCID iD:FMM: http://orcid.org/0000-0001-9615-2540
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Palumbo Piccionello, Angela, Alberto Salvaggio, Antonella Volta, Fabiola Emiliozzi, Riccardo Botto, Fabrizio Dini, and Massimo Petazzoni. "Good Inter- and Intra-Observer Reliability for Assessment of Radiographic Femoral and Tibial Frontal and Sagittal Planes Joints Angles in Normal Cats." Veterinary and Comparative Orthopaedics and Traumatology 33, no. 05 (May 14, 2020): 308–15. http://dx.doi.org/10.1055/s-0040-1709694.
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Abstract Objective The aim of this study was to evaluate the inter- and intra-observer reliability of plain digital radiographs for assessing normal feline femoral and tibial joint reference angles in the sagittal and frontal planes. Study Design This was a cadaveric radiographic anatomical study. that involved 20 short-haired domestic adult cats. Materials and Methods Sagittal and frontal plane tibial and femoral joint angles of 40 limbs were measured twice by three observers with different levels of experience. Inter- and intraobserver reliability was determined by the intra-class correlation coefficient (ICC). An ICC > 0.75 was considered high correlation, 0.74 > ICC > 0.60 good correlation, 0.59 > ICC > 0.4 fair correlation and an ICC < 0.40 poor correlation. Results Mean ± standard deviation angles were anatomic lateral proximal femoral angle (aLPFA) 110.6 ± 3.6; anatomic lateral distal femoral angle (aLDFA) 91.9 ± 2.1; mechanical lateral proximal femoral angle; mLPFA (mLPFA) 107.3 ± 3.6; mechanical lateral distal femoral angle (mLDFA) 95.5 ± 1.7; femoral neck anteversion (FNA) 121.9 ± 4.1; anatomical caudal proximal femoral angle (aCPFA) 156.1 ± 3.9; anatomical caudal distal femoral angle (aCDFA) 101.4 ± 1.4; mechanical medial proximal tibial angle (mMPTA) 93.5 ± 1.2; mechanical medial distal tibial angle (mMDTA) 100.5 ± 2.3; mechanical cranial proximal tibial angle (mCrPTA) 113.1 ± 3.2; tibial plateau angle (TPA) 23.1 ± 3.2; mechanical cranial proximal tibial angle (mCrDTA) 86.7 ± 3.1.The intra-observer ICC indicated high correlation for 70% or more of the measurements. The inter-observer agreement among observers was high. These results show that the radiographic method for measuring femoral and tibial joint angles was good or high, except for FNA and mCrDTA. Conclusions This study provides some radiographic anatomical and mechanical joint angles of the femurs and tibias of normal domestic short-haired cats. We found good reliability for both intra- and interobserver measurements.
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Cabassu, Julien. "Minimally Invasive Plate Osteosynthesis Using Fracture Reduction Under the Plate without Intraoperative Fluoroscopy to Stabilize Diaphyseal Fractures of the Tibia and Femur in Dogs and Cats." Veterinary and Comparative Orthopaedics and Traumatology 32, no. 06 (July 29, 2019): 475–82. http://dx.doi.org/10.1055/s-0039-1693413.
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Objective The aim of this study was to prospectively evaluate postoperative alignment when using fracture reduction under the plate (FRUP) during a minimally invasive plate osteosynthesis in tibial and femoral fractures, without intraoperative imaging, and report immediate postoperative complications. Materials and Methods After precise plate contouring and preoperative planning, FRUP was obtained with one cortical screw per fragment. Fractures were stabilized with a plate or plate rod. Tibial/femoral lengths, tibial plateau angles, mechanical medial proximal and distal tibial angles, anatomical lateral distal femoral angles, femoral curvatum and neck anteversion were evaluated on postoperative radiographs and contralateral bone. Tibial torsion was evaluated visually. Paired t-test were used to compare data. Immediate postoperative complications were recorded. Results Twenty-one tibial and 20 femoral fractures were stabilized (14 plate rod cases). Mean postoperative operated tibial length was 1.4% shorter (p = 0.001). Mean postoperative operated femoral length was 2% shorter (p = 0.04). Mean operated tibial plateau angle was 1.1° lower (p = 0.02). No difference in tibial torsion was noticed. No significant difference in mechanical medial proximal tibial angle, mechanical medial distal tibial angle, anatomical lateral distal femoral angle and femoral neck anteversion was observed. Mean operated femoral curvatum angle was 5.6° less (p = 0.01). Five cases (3 plate rod cases) required an immediate revision. Clinical Significance Minimally invasive plate osteosynthesis with FRUP leads to acceptable postoperative alignment. Correct pin placement should be evaluated.
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Ucpunar, H., S. K. Tas, Y. Camurcu, H. Sofu, M. Mert, and A. I. Bayhan. "The effects of residual hip deformity on coronal alignment of the lower extremity in patients with unilateral slipped capital femoral epiphysis." Journal of Children's Orthopaedics 12, no. 6 (December 2018): 599–605. http://dx.doi.org/10.1302/1863-2548.12.180137.
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Purpose The aim of our explorative study was to compare the differences in the coronal alignments of the hip, knee and ankle on the slip side and non-slip sides in patients with slipped capital femoral epiphysis (SCFE). Methods The study group consisted of 28 patients. On the full-length standing radiographs, measurements of articulo-trochanteric distance (ATD), neck-shaft angle (NSA), femoral offset, hip-knee-ankle axis, femur-tibial angle, mechanical axis deviation ratio (MAD-r), anatomical medial proximal femoral angle (aMPFA), mechanical lateral proximal femoral angle (mLPFA), anatomical lateral distal femoral angle (aLDFA), mechanical lateral distal femoral angle (mLDFA), knee joint line congruency angle, mechanical medial proximal tibial angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), ankle joint line orientation angle (AJOA), and leg length discrepancy (LLD) were performed. The data from the slip side were compared with those from the non-slip side. Results At skeletal maturity, there were significant differences between the slip side and non-slip side in ATD (p <0.001), NSA (p <0.001), MAD-r (p <0.001), aMPFA (p <0.001), aLDFA (p = 0.03), mLDFA (p = 0.04), mLDTA (p = 0.02), AJOA (p <0.001) and LLD (p<0.001). Conclusion Residual deformity in the proximal femur after epiphyseal slip and premature epiphysiodesis could cause changes in the coronal alignment of the lower extremity. We can add lower extremity alignment examination to follow-up protocol to rule out secondary problems in patients with SCFE. Level of Evidence Level III, retrospective comparative study
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Fonseca, R. L., A. R. Lobo-Jr, and M. I. S. Santana. "Measurements of femoral angles, femur length, and hip width in cat radiographs." Arquivo Brasileiro de Medicina Veterinária e Zootecnia 69, no. 6 (November 2017): 1513–20. http://dx.doi.org/10.1590/1678-4162-9583.
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ABSTRACT Femoral angle, femur length, and hip width were measured in radiographs of 92 intact domestic cats, males and females of mixed breed from the Center for Zoonosis Control of the Federal District. The animals showed no trauma, orthopedic diseases or angular deformities and had closed physeal lines. Accordingly, we measured aLPFA (anatomical lateral proximal femoral angle, aLDFA (anatomical lateral distal femoral angle), mLPFA (mechanical lateral proximal femoral angle), mLDFA (mechanical lateral distal femoral angle), IA (femoral inclination angle), FL (femur length) and HW (hip width) using ventrodorsal radiographs, with both hindlimbs in a single exposure to an X-ray beam centered on the hip. The mean values of the variables were: mLPFA: 82.5±3.62°; aLPFA: 80.1±4.29°; mLDFA: 96.1±3.51° (males) and 97.3±2.05° (females); aLDFA: 94,3±3.43°; IA: 136.6±3.86°; FL: 12.9±0.55cm (males) and 13.4±0.66cm (females); and HW: 3.1cm±0.23 (males) and 3.5±0.26cm (females). These values will serve as a reference for the diagnosis of angular deformities and as support for planning corrective osteotomies in domestic cats.
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Yasukawa, Shinji, Koji Tanegashima, Mamiko Seki, Kenji Teshima, Kazushi Asano, Tomohiro Nakayama, Kei Hayashi, and Kazuya Edamura. "Evaluation of bone deformities of the femur, tibia, and patella in Toy Poodles with medial patellar luxation using computed tomography." Veterinary and Comparative Orthopaedics and Traumatology 29, no. 01 (January 2016): 29–38. http://dx.doi.org/10.3415/vcot-15-05-0089.
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SummaryObjectives: To evaluate morphological parameters of the femur, tibia, and patella in Toy Poodles with medial patellar luxation (MPL) using three-dimensional (3D) computed tomography (CT) and to compare these parameters between radiography and CT.Methods: Thirty-five hindlimbs of Toy Poodles were divided into normal and grade 2 and 4 MPL groups. The anatomical and mechanical lateral proximal femoral angle, anatomical and mechanical lateral distal femoral angle (aLDFA, mLDFA), femoral varus angle (FVA), inclination of the femoral head angle, procurvation angle, anteversion angle (AA), frontal angle of the femoral neck, mechanical medial proximal or distal tibial angle, mechanical cranial proximal or distal tibial angle, tibial plateau angle, tibial torsion angle (TTA), Z angle, relative tibial tuberosity width, ratio of the medial distance of tibial tuberosity to the proximal tibial width (MDTT/PTW), patella size, and the patellar ligament length: patellar length (L:P) ratio were evaluated on radiography and 3D CT.Results: The aLDFA, mLDFA, FVA, and TTA were significantly larger and the AA, MDTT/ PTW, and patella were significantly smaller in the grade 4 MPL group. There were significant differences in many parameters between imaging tools, and CT was considered less susceptible to potential artefacts and rotational deformities.Clinical significance: Toy Poodles with grade 4 MPL had significant femoral varus deformity, medial displacement of the tibial tuberosity, internal torsion of the proximal tibia, and hypoplasia of the patella.
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Soparat, C., C. Wangdee, S. Chuthatep, and M. Kalpravidh. "Radiographic measurement for femoral varus in Pomeranian dogs with and without medial patellar luxation." Veterinary and Comparative Orthopaedics and Traumatology 25, no. 03 (2012): 197–201. http://dx.doi.org/10.3415/vcot-11-04-0057.
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SummaryObjectives: To measure radiographically the inclination angle (ICA), femoral varus angle (FVA), anatomical lateral distal femoral angle (aLDFA), and mechanical lateral distal femoral angle (mLDFA) in Pomeranian dogs with and without medial patellar luxation (MPL).Materials and methods: Stifles of 34 Pomeranian dogs were graded and allocated into three groups: normal, grades I-II MPL, and grade III MPL. Angle values were measured from craniocaudal radiographs of the hindlimbs by each of the three examiners on three separate occasions.Results: Each of the three groups consisted of 15 stifles. Means ± SD for the ICA, FVA, aLDFA and mLDFA in the normal stifles were 136.46 ± 7.12°, 5.85 ± 3.18°, 95.21 ± 3.48° and 99.46 ± 4°, respectively. No significant differences (p >0.05) in the measured values for the ICA between groups were observed. The FVA, aLDFA and mLDFA values in grade III MPL group were significantly (p <0.05) greater than those in the other two groups. Significant differences in the three angles between the normal and grades I-II MPL groups were not observed.Clinical significance: Significant change of distal femoral varus exists in Pomeranian dogs with grade III MPL.
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Maderbacher, Günther, Jan Matussek, Felix Greimel, Joachim Grifka, Jens Schaumburger, Clemens Baier, and Armin Keshmiri. "Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors." Journal of Knee Surgery 34, no. 01 (July 29, 2019): 108–14. http://dx.doi.org/10.1055/s-0039-1693668.
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AbstractWeight-bearing long-leg radiographs are commonly used in orthopaedic surgery. Measured parameters, however, change when radiographs are conducted in different rotational positions of the leg. It was hypothesized that rotational errors are regularly present in long-leg radiographs resulting in wrong measurements. In 100 consecutive long-leg radiographs conducted according to the method of Paley, rotation was assessed by fibular overlap. Angular parameters in radiographs (mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle between the anatomical and mechanical femoral axis (AMA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), and the mechanical femoral and tibial axis (mFA–mTA) were measured and deviations related to malrotation calculated. An average internal rotation of 8 degrees was found in lower limbs showing a range between 29 degrees of internal and 22 degrees of external rotation. As a result, mean differences before and after rotational correction for measured parameters (mLPFA, mLDFA, AMA, mMPTA, mLDTA, mFA–mTA) ranged between 0.4 and 1.7 degrees (−2.1; 5.6 95% confidence interval [CI]). In conclusion, malrotation of lower limbs is regularly present in long-leg radiographs. As all measured parameters are influenced by malrotation, correct lower limb rotation needs to be verified.
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Mathew, Smitha E., Todd A. Milbrandt, and Megan L. Young. "Lateral Opening Wedge Osteotomy of the Distal Femur for Genu Valgum." Journal of the Pediatric Orthopaedic Society of North America 4, no. 3 (August 1, 2022): 1–11. http://dx.doi.org/10.55275/jposna-2022-0033.
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Genu valgum is a risk factor for patellofemoral maltracking and recurrent instability and may cause mechanical overload of the lateral compartment leading to early arthritic changes in some patients. In skeletally mature adolescents, a varus-producing distal femoral osteotomy will correct the valgus malalignment when the femur contributes to the overall lower extremity deformity. The goal of a distal femoral osteotomy is to correct the lateral distal femur joint angle and restore a neutral mechanical axis through the center of the knee joint. We aim to discuss the indications and contraindications, pros and cons, preoperative planning, osteotomy options, surgical techniques, and postoperative protocol for a distal femur corrective osteotomy.
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Suvarly, Prettysia, Nyoman Aditya Sindunata, Rio Aditya, Rusli Muljadi, and John Butarbutar. "Femoral Shaft Bowing Angle in The Coronal Plane Affects Distal Femoral Valgus Cutting Angle: A Radiographic Study." Orthopaedic Journal of Sports Medicine 8, no. 5_suppl5 (May 1, 2020): 2325967120S0004. http://dx.doi.org/10.1177/2325967120s00047.
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Postoperative limb alignment is important for successful total knee arthroplasty (TKA). Femoral shaft bowing angle (FBA) in coronal plane may influence distal femoral valgus cutting angle (DFVCA) and 5±2º may not perpendicular to mechanical axis. Methods: Sixty-six lower extremity long film x-ray of osteoarthritic knees were collected and analyzed with IntstaRISPACS (digital radiography software). The correlation and linear regression between FBA and DFVCAwere measured using SPSS 24. Results: Our study shows a strong correlation between FBA and DFVCA. Lateral FBA tends to present with DFVCA outside 7º as shown in linear regression test, vice versa. Conclusion: Since DFVCA is influenced by FBA, we recommend preoperative femoral x-ray in all knee replacement candidates. References: Rezende FC, Carneiro M. Is it safe the empirical distal femoral resection angle of 5° to 6°of valgus in the Brazilian geriatric population? Rev Bras Orthop. 2013; 48(5): 421-6. Kim CW, Lee CR. Effects of femoral lateral bowing on coronal alignment and component position after total knee arthroplasty: a comparison of conventional and navigation-assisted surgery. Knee Surg Relat Res. 2018 Mar; 30(1): 64–73. Kim JM, Hong SH, Kim JM, Lee BS, Kim DE, Kim KA, Bin et al. Femoral shaft bowing in the carinal plane has more significant effect on the coronal alignment of TKA than proximal or distal variations of femoral shape. Knee Surg Sports Traumatol Arthrosc. 2015;23(7):1936-42
Book chapters on the topic "Mechanical lateral distal femoral angle"
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V. Patel, Deepak, Iciar M. Dávila Castrodad, Jennifer Kurowicki, Vincent K. McInerney, and Anthony J. Scillia. "Patellofemoral Instability." In Arthroscopy. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.99562.
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Recurrent patellofemoral instability is a common cause of knee pain and functional disability in adolescent and young adult patients, resulting in loss of time from work and sports. There are numerous factors that contribute to recurrent patellofemoral instability; these factors include tear of the medial patellofemoral ligament (MPFL), weakening or hypoplasia of the vastus medialis obliquus (VMO), trochlear dysplasia, increased tibial tuberosity-trochlear groove (TT-TG) distance (>20 mm), valgus malalignment, increased Q angle, malrotation secondary to internal femoral or external tibial torsion, patella alta, and generalized ligamentous laxity. A detailed history and a thorough physical examination are crucial to clinch an early, accurate diagnosis. Imaging studies play an important role to confirm the clinical diagnosis and also help to identify concomitant intra-articular pathologies. Initially, nonoperative management (including the use of physical therapy, patellar taping or brace) is offered to patients with acute, first-time patellar dislocations and most patients respond well to this mode of treatment. Surgical treatment is indicated for patients who have post-trauma osteochondral fracture or loose body; predisposing anatomical risk factors; recurrent, symptomatic instability; and who have failed an adequate trial of nonoperative management. Surgical treatments include MPFL reconstruction, proximal or distal realignment procedures, and trochleoplasty. Lateral release is often performed in combination with other procedures and seldom performed as an isolated procedure. An individualized case-by-case approach is recommended based on the underlying anatomical risk factors and radiographic abnormality.
Conference papers on the topic "Mechanical lateral distal femoral angle"
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Higa, Masaru, Ikuya Nishimura, Hiromasa Tanino, and Yoshinori Mitamura. "Shape Opimization of Femoral Components of an Artificial Hip Prosthesis Using the Three-Dimensional P-Version Finite Element Method." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/bed-23012.
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Abstract The three-dimensional shape optimization of cemented total hip arthroplasty (THA) was introduced in this paper. The P-version Finite Element Method (FEM) combined with an optimization procedure was used to minimize the peak stress in the bone cement near the tip of the implant. Six-design variables were used in this study. Each variable represents the dimension of the medial-lateral width and anterior-posterior width of the three levels (proximal, distal and middle) of cross sectional area of the prosthesis. The results of the design optimization showed considerable reduction in stress concentration compared to the initial design that is currently used clinically.
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Petrella, Anthony J., Alexandros Karmas, Mark C. Miller, Richard A. Berger, and Harry E. Rubash. "Medial Placement of the Patellar Button Improves Contact Pressure Distribution Following Total Knee Arthroplasty." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0450.
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Abstract Total knee arthroplasty is now a common and successful means of treating osteoarthritis and other degenerative conditions in the knee joint. Historically, mechanical failures (e.g. button loosening or separation from the metal backing) and chronic subluxation have been among the most common complications associated with the patello-femoral joint. Advances in fixation, implant design, and surgical technique have lead to a decrease in the incidence of mechanical failures, but restoration of stable function to the distal extensor mechanism remains challenging. The center of pressure (COP) on the patellar implant is an indication of the distribution of contact forces on the device and of the stability of patellar tracking. An eccentric COP suggests the possibility of subluxation, high contact stresses, and increased patellar wear. The main objective of this study was to determine the affect of medial-lateral patellar placement on the COP of the patellar implant. It was hypothesized that medial-lateral placement of the patella would have a significant effect on the COP.
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Tarlochan, Faris, and Hassan Mehboob. "A Need for Functionally Graded Stiffness Femoral Stem for Reduction in Stress Shielding and Promoting Bone Growth: Computational Analysis." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70675.
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Total Hip Arthroplasty (THA) is an orthopaedic procedure that is available to reduce pain and restore the functionality of hip joints. THA has been successfully implemented for the last 40 years. However, after more than 40 years of design and implementation, premature loosening of the femoral stem still occurs due to the stress shielding. Stress shielding can be reduced by using implants with lower stiffness. This however, could increase the micromotion and interface debonding between the stem and femur bone. The aim of this study is to investigate stress and micromotion distribution across the length of the stem and to develop a bone in growth simulation model. To achieve this, a bone growth mechano-regulation algorithm based on deviatoric strain was applied to study the tissue differentiation process. The initial outcome of the study indicates that the stiffness of the implant should not be uniform rather graded from the distal to proximal and lateral to medial directions of the implant. With such graded stiffness, bone growth density was possible across the entire length of the stem, hence reducing aseptic loosening due to stress shielding.
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Patel, Bipin, Peter A. Gustafson, and James Jastifer. "Stiffness of Locking and Conventional Plates in Fixation of Distal Fibula Fractures: A Finite Element Study." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40729.
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The objective of this study is to establish and differentiate the stiffness of conventional and fixed angle screw constructs for the treatment of distal fibula fractures. Two plate types are examined; a fibular neutralization plate and a lateral periarticular distal fibular plate with fixed angle (locked) screws. The neutralization plate is considered with two construct types; conventional and locked screws. Several comparisons were made to differentiate the stiffness of the plate constructs. First, the neutralization plate is examined with conventional and locked screws when used for fixation of Danis-Weber B and comminuted fractures. Second, neutralization and periarticular plates are compared with locked screws for the same fracture patterns. The stiffnesses of the constructs are computed with the finite element method based on several load cases. The type of screw construct is found to have minimal effect on the stiffness, whereas the plate type is found to have a larger influence due to geometrical differences. The comparison is limited to stiffness; the strength of the constructs should be examined in future work.
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Miller, Emily J., Mark W. Pagnano, and Kenton R. Kaufman. "Tibiofemoral Alignment for Total Knee Arthroplasty: Differences Between Static and Dynamic Tibial Plateau Loading." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19139.
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The surgical goal in total knee arthroplasty (TKA) is to obtain neutral mechanical alignment within three degrees [4]. This has been considered necessary to achieve optimal function, produce balanced medial and lateral loading distributions, and prolong implant longevity [7]. Under static loading, tibial-femoral alignment angle deviations of 3° have been shown to greatly alter the distribution of pressure and load between the medial and lateral tibial plateaus [13]. However, other studies have challenged the practice that coronal tibiofemoral alignment improves implant longevity [9,10]. These studies did not show a statistical difference in the number of revision surgeries between well aligned knees and mechanical alignment outliers (varus/valgus knees). While it has been suggested that accurate alignment allows for improved joint kinematics and improved outcomes in TKA patients [6], no studies have evaluated the effect of tibial-femoral alignment on tibial plateau loading distribution during gait in the TKA population. Therefore, the purpose of this study was to assess tibial plateau loading following TKA.
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Yang, Nicholas H., H. Nayeb-Hashemi, and Paul K. Canavan. "The Effects of Tibiofemoral Angle and Body Weight on the Stress Field in the Knee Joint." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41344.
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Osteoarthritis (OA) is a degenerative disease of articular cartilage that may lead to pain, limited mobility and joint deformation. It has been reported that abnormal stresses and irregular stress distribution may lead to the initiation and progression of OA. Body weight and the frontal plane tibiofemoral angle are two biomechanical factors which could lead to abnormal stresses and irregular stress distribution at the knee. The tibiofemoral angle is defined as the angle made by the intersection of the mechanical axis of the tibia with the mechanical axis of the femur in the frontal plane. In this study, reflective markers were placed on the subjects’ lower extremity bony landmarks and tracked using motion analysis. Motion analysis data and force platform data were collected together during single-leg stance, double-leg stance and walking gait from three healthy subjects with no history of osteoarthritis (OA), one with normal tibiofemoral angle (7.67°), one with varus (bow-legged) angle (0.20°) and one with valgus (knocked-knee) angle (10.34°). The resultant moment and forces in the knee were derived from the data of the motion analysis and force platform experiments using inverse dynamics. The results showed that Subject 1 (0.20° valgus) had a varus moment of 0.38 N-m/kg, during single-leg stance, a varus moment of 0.036 N-m/kg during static double-leg stance and a maximum varus moment of 0.49 N-m/kg during the stance phase of the gait cycle. Subject 2 (7.67° valgus tibiofemoral angle) had a varus moment of 0.31 N-m/kg, during single-leg stance, a valgus moment of 0.046 N-m/kg during static double-leg stance and a maximum varus moment of 0.37 N-m/kg during the stance phase of the gait cycle. Subject 3 (10.34° valgus tibiofemoral angle) had a varus moment of 0.30 N-m/kg, during single-leg stance, a valgus moment of 0.040 N-m/kg during static double-leg stance and a maximum varus moment of 0.34 N-m/kg during the stance phase of the gait cycle. In general, the results show that the varus moment at the knee joint increased with varus knee alignment in static single-leg stance and gait. The results of the motion analysis were used to obtain the knee joint contact stress by finite element analysis (FEA). Three-dimensional (3-D) knee models were constructed with sagittal view MRI of the knee. The knee model included the bony geometry of the knee, the femoral and tibial articular cartilage, the lateral and medial menisci and the cruciate and the collateral ligaments. In initial FEA simulations, bones were modeled as rigid, articular cartilage was modeled as isotropic elastic, menisci were modeled as transversely isotopic elastic, and the ligaments were modeled as 1-D nonlinear springs. The material properties of the different knee components were taken from previously published literature of validated FEA models. The results showed that applying the axial load and varus moment determined from the motion analysis to the FEA model Subject 1 had a Von Mises stress of 1.71 MPa at the tibial cartilage while Subjects 2 and 3 both had Von Mises stresses of approximately 1.191 MPa. The results show that individuals with varus alignment at the knee will be exposed to greater stress at the medial compartment of the articular cartilage of the tibia due to the increased varus moment that occurs during single leg support.