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Thomas Lang - One of the best experts on this subject based on the ideXlab platform.
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automatic multi parametric quantification of the Proximal Femur with quantitative computed tomography
Quantitative imaging in medicine and surgery, 2015Co-Authors: Julio Carballidogamio, Joyce H. Keyak, Serena Bonaretti, Isra Saeed, Roy Harnish, Robert R Recker, Andrew J Burghardt, Tamara B Harris, Sundeep Khosla, Thomas LangAbstract:Background: Quantitative computed tomography (QCT) imaging is the basis for multiple assessments of bone quality in the Proximal Femur, including volumetric bone mineral density (vBMD), tissue volume, estimation of bone strength using finite element modeling (FEM), cortical bone thickness, and computational-anatomy-based morphometry assessments. Methods: Here, we present an automatic framework to perform a multi-parametric QCT quantification of the Proximal Femur. In this framework, the Proximal Femur is cropped from the bilateral hip scans, segmented using a multi-atlas based segmentation approach, and then assigned volumes of interest through the registration of a Proximal femoral template. The Proximal Femur is then subjected to compartmental vBMD, compartmental tissue volume, FEM bone strength, compartmental surface-based cortical bone thickness, compartmental surface-based vBMD, local surface-based cortical bone thickness, and local surface-based cortical vBMD computations. Consequently, the template registrations together with vBMD and surface-based cortical bone parametric maps enable computational anatomy studies. The accuracy of the segmentation was validated against manual segmentations of 80 scans from two clinical facilities, while the multi-parametric reproducibility was evaluated using repeat scans with repositioning from 22 subjects obtained on CT imaging systems from two manufacturers. Results: Accuracy results yielded a mean dice similarity coefficient of 0.976±0.006, and a modified Haussdorf distance of 0.219±0.071 mm. Reproducibility of QCT-derived parameters yielded root mean square coefficients of variation (CV RMS ) between 0.89-1.66% for compartmental vBMD; 0.20-1.82% for compartmental tissue volume; 3.51-3.59% for FEM bone strength; 1.89-2.69% for compartmental surface-based cortical bone thickness; and 1.08-2.19% for compartmental surface-based cortical vBMD. For local surface-based assessments, mean CV RMS were between 3.45-3.91% and 2.74-3.15% for cortical bone thickness and vBMD, respectively. Conclusions: The automatic framework presented here enables accurate and reproducible QCT multi-parametric analyses of the Proximal Femur. Our subjects were elderly, with scans obtained across multiple clinical sites and manufacturers, thus documenting its value for clinical trials and other multi-site studies.
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adaptation of the Proximal Femur to skeletal reloading after long duration spaceflight
Journal of Bone and Mineral Research, 2006Co-Authors: Thomas Lang, Adrian Leblanc, Harlan J Evans, Ying LuAbstract:We studied the effect of re-exposure to Earth's gravity on the Proximal femoral BMD and structure of astronauts 1 year after missions lasting 4–6 months. We observed that the readaptation of the Proximal Femur to Earth's gravity entailed an increase in bone size and an incomplete recovery of volumetric BMD. Introduction: Bone loss is a well-known result of skeletal unloading in long-duration spaceflight, with the most severe losses occurring in the Proximal Femur. However, there is little information about the recovery of bone loss after mission completion and no information about effect of reloading on the structure of load-bearing bone. To address these questions, we carried out a study of the effect of re-exposure to Earth's gravity on the BMD and structure of the Proximal Femur 1 year after missions lasting 4–6 months. Materials and Methods: In 16 crew members of the International Space Station (ISS) making flights of 4.5–6 months, we used QCT imaging to measure the total, trabecular, and cortical volumetric BMD (vBMD) of the Proximal Femur. In addition to vBMD, we also quantified BMC, bone volume, femoral neck cross-sectional area (CSA), and femoral neck indices of compressive and bending strength at three time-points: preflight, postflight, and 1 year after mission. Results: Proximal femoral bone mass was substantially recovered in the year after spaceflight, but measures of vBMD and estimated bone strength showed only partial recovery. The recovery of BMC, in the absence of a comparable increase in vBMD, was explained by increases in bone volume and CSA during the year after spaceflight. Conclusions: Adaptation of the Proximal Femur to reloading entailed an increase in bone size and an incomplete recovery of vBMD. The data indicate that recovery of skeletal density after long-duration space missions may exceed 1 year and supports the evidence in the aging literature for periosteal apposition as a compensatory response for bone loss. The extent to which this compensatory effect protects against fracture remains to be seen.
A Murty - One of the best experts on this subject based on the ideXlab platform.
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Do Proximal Femur locking plates work
2018Co-Authors: B. Purushothaman, K. Rankin, P. Bansal, A MurtyAbstract:AimTo review the results of patients who underwent fixation of complex Proximal Femur fractures using the Proximal Femur Locking Plates (PFP) and analyse causes of failure of PFP.MethodsRetrospecti...
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Do Proximal Femur locking plates work
Journal of Bone and Joint Surgery-british Volume, 2013Co-Authors: B. Purushothaman, K. Rankin, P. Bansal, A MurtyAbstract:Aim To review the results of patients who underwent fixation of complex Proximal Femur fractures using the Proximal Femur Locking Plates (PFP) and analyse causes of failure of PFP. Methods Retrospective review of radiographs and case notes of PFP fixations in two hospitals between February 2008 and June 2011. Primary outcome was union at six months. Secondary outcome included post-operative complications, and need for further surgical intervention. Results There were a total of 32 patients who underwent 34 operations. Two patient had fracture of both the Proximal Femur requiring bilateral PFP fixation. Mean age of the patients was 68.4 years (range 17–96 years). There were twelve males and twenty female patients. 26 (81%) of the operations were done as primary surgery for fixation of the complex Proximal Femur fractures. According to the AO/OTA fracture classification, there were four cases of 31-A2.2, seven cases of 31-A2.3, two cases of 31-A3.1 one case each of 31-A3.2 and 32-B1.1 and ten cases of 31 A3.3 fractures. At least six months of follow up was achieved for 30 cases. Union was achieved in 20 fixations (62%) primarily; two more cases needed bone grafting at three months which went on to union improving the total union rate to 70% at 6 months. There was failure of fixation in eight cases requiring further surgery. Varus fixation, loss of posteromedial buttress and loss of protected weight bearing were associated with fixation failure. Conclusion Contrary to the reported literature, (1) our results are better. Analysis of the failure cases emphasises the importance of postero medial buttress restoration, avoidance of varus fixation, and protection of weight bearing till fracture unites to achieve good outcome.
Matthew R Steensma - One of the best experts on this subject based on the ideXlab platform.
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endoprosthetic treatment is more durable for pathologic Proximal Femur fractures
Clinical Orthopaedics and Related Research, 2012Co-Authors: Matthew R Steensma, Patrick J Boland, Carol D Morris, Edward A Athanasian, John H HealeyAbstract:Background Pathologic Proximal Femur fractures result in substantial morbidity for patients with skeletal metastases. Surgical treatment is widely regarded as effective; however, failure rates associated with the most commonly used operative treatments are not well defined.
Joyce H. Keyak - One of the best experts on this subject based on the ideXlab platform.
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Physical Activity for Strengthening Fracture Prone Regions of the Proximal Femur
Current Osteoporosis Reports, 2017Co-Authors: Robyn K. Fuchs, Mariana E. Kersh, Julio Carballido-gamio, William R. Thompson, Joyce H. Keyak, Stuart J. WardenAbstract:Purpose of Review Physical activity improves Proximal femoral bone health; however, it remains unclear whether changes translate into a reduction in fracture risk. To enhance any fracture-protective effects of physical activity, fracture prone regions within the Proximal Femur need to be targeted. Recent Findings The Proximal Femur is designed to withstand forces in the weight-bearing direction, but less so forces associated with falls in a sideways direction. Sideways falls heighten femoral neck fracture risk by loading the relatively weak superolateral region of femoral neck. Recent studies exploring regional adaptation of the femoral neck to physical activity have identified heterogeneous adaptation, with adaptation principally occurring within inferomedial weight-bearing regions and little to no adaptation occurring in the superolateral femoral neck. Summary There is a need to develop novel physical activities that better target and strengthen the superolateral femoral neck within the Proximal Femur. Design of these activities may be guided by subject-specific musculoskeletal modeling and finite-element modeling approaches.
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automatic multi parametric quantification of the Proximal Femur with quantitative computed tomography
Quantitative imaging in medicine and surgery, 2015Co-Authors: Julio Carballidogamio, Joyce H. Keyak, Serena Bonaretti, Isra Saeed, Roy Harnish, Robert R Recker, Andrew J Burghardt, Tamara B Harris, Sundeep Khosla, Thomas LangAbstract:Background: Quantitative computed tomography (QCT) imaging is the basis for multiple assessments of bone quality in the Proximal Femur, including volumetric bone mineral density (vBMD), tissue volume, estimation of bone strength using finite element modeling (FEM), cortical bone thickness, and computational-anatomy-based morphometry assessments. Methods: Here, we present an automatic framework to perform a multi-parametric QCT quantification of the Proximal Femur. In this framework, the Proximal Femur is cropped from the bilateral hip scans, segmented using a multi-atlas based segmentation approach, and then assigned volumes of interest through the registration of a Proximal femoral template. The Proximal Femur is then subjected to compartmental vBMD, compartmental tissue volume, FEM bone strength, compartmental surface-based cortical bone thickness, compartmental surface-based vBMD, local surface-based cortical bone thickness, and local surface-based cortical vBMD computations. Consequently, the template registrations together with vBMD and surface-based cortical bone parametric maps enable computational anatomy studies. The accuracy of the segmentation was validated against manual segmentations of 80 scans from two clinical facilities, while the multi-parametric reproducibility was evaluated using repeat scans with repositioning from 22 subjects obtained on CT imaging systems from two manufacturers. Results: Accuracy results yielded a mean dice similarity coefficient of 0.976±0.006, and a modified Haussdorf distance of 0.219±0.071 mm. Reproducibility of QCT-derived parameters yielded root mean square coefficients of variation (CV RMS ) between 0.89-1.66% for compartmental vBMD; 0.20-1.82% for compartmental tissue volume; 3.51-3.59% for FEM bone strength; 1.89-2.69% for compartmental surface-based cortical bone thickness; and 1.08-2.19% for compartmental surface-based cortical vBMD. For local surface-based assessments, mean CV RMS were between 3.45-3.91% and 2.74-3.15% for cortical bone thickness and vBMD, respectively. Conclusions: The automatic framework presented here enables accurate and reproducible QCT multi-parametric analyses of the Proximal Femur. Our subjects were elderly, with scans obtained across multiple clinical sites and manufacturers, thus documenting its value for clinical trials and other multi-site studies.
B. Purushothaman - One of the best experts on this subject based on the ideXlab platform.
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Do Proximal Femur locking plates work
2018Co-Authors: B. Purushothaman, K. Rankin, P. Bansal, A MurtyAbstract:AimTo review the results of patients who underwent fixation of complex Proximal Femur fractures using the Proximal Femur Locking Plates (PFP) and analyse causes of failure of PFP.MethodsRetrospecti...
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Do Proximal Femur locking plates work
Journal of Bone and Joint Surgery-british Volume, 2013Co-Authors: B. Purushothaman, K. Rankin, P. Bansal, A MurtyAbstract:Aim To review the results of patients who underwent fixation of complex Proximal Femur fractures using the Proximal Femur Locking Plates (PFP) and analyse causes of failure of PFP. Methods Retrospective review of radiographs and case notes of PFP fixations in two hospitals between February 2008 and June 2011. Primary outcome was union at six months. Secondary outcome included post-operative complications, and need for further surgical intervention. Results There were a total of 32 patients who underwent 34 operations. Two patient had fracture of both the Proximal Femur requiring bilateral PFP fixation. Mean age of the patients was 68.4 years (range 17–96 years). There were twelve males and twenty female patients. 26 (81%) of the operations were done as primary surgery for fixation of the complex Proximal Femur fractures. According to the AO/OTA fracture classification, there were four cases of 31-A2.2, seven cases of 31-A2.3, two cases of 31-A3.1 one case each of 31-A3.2 and 32-B1.1 and ten cases of 31 A3.3 fractures. At least six months of follow up was achieved for 30 cases. Union was achieved in 20 fixations (62%) primarily; two more cases needed bone grafting at three months which went on to union improving the total union rate to 70% at 6 months. There was failure of fixation in eight cases requiring further surgery. Varus fixation, loss of posteromedial buttress and loss of protected weight bearing were associated with fixation failure. Conclusion Contrary to the reported literature, (1) our results are better. Analysis of the failure cases emphasises the importance of postero medial buttress restoration, avoidance of varus fixation, and protection of weight bearing till fracture unites to achieve good outcome.
