Effect of simulated metastatic lesions on the biomechanical behavior of the proximal femur

Benca, Emir; Reisinger, Andreas; Patsch, Janina; Hirtler, Lena; Synek, Alexander; Stenicka, Sandra; Windhager, Reinhard; Mayr, Winfried; Pahr, Dieter H.

doi:10.1002/jor.23550

Cited by 30 publications

(40 citation statements)

References 35 publications

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“…Tests were performed on intact specimens as well as on specimens with simulated metastatic lesions. The results of the mechanical experiments were published previously 11 . Nonlinear hvFE models were generated from QCT images and validated with data assessed in mechanical experiments on specimens under careful consideration of experimental boundary conditions.…”

Section: Methodsmentioning

confidence: 99%

“…Based on clinical distribution in patients who suffered a pathologic fracture ( d ), metastatic lesions were simulated in either the superolateral or inferomedial neck in one femur of each pair ( e ), followed by a second QCT scan and stiffness test. All femora were then subjected to an ultimate biomechanical test to determine failure load 11 ( f ). A FE model was generated based on geometry and bone density distribution (BV/TV) retrieved from QCT images ( g ).…”

Section: Methodsmentioning

confidence: 99%

“…Assessing strength of a metastatic bone requires information on its geometry, three-dimensional distribution of density 8 , the size 9 , shape 10 , site 11 , and nature of the lesion 6,12 , as well as on the patient’s loading regimen and activity level.…”

Section: Introductionmentioning

confidence: 99%

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QCT-based finite element prediction of pathologic fractures in proximal femora with metastatic lesions

Benca

Synek

Amini

et al. 2019

Sci Rep

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Predicting pathologic fractures in femora with metastatic lesions remains a clinical challenge. Currently used guidelines are inaccurate, especially to predict non-impeding fractures. This study evaluated the ability of a nonlinear quantitative computed tomography (QCT)-based homogenized voxel finite element (hvFE) model to predict patient-specific pathologic fractures. The hvFE model was generated highly automated from QCT images of human femora. The femora were previously loaded in a one-legged stance setup in order to assess stiffness, failure load, and fracture location. One femur of each pair was tested in its intact state, while the contralateral femur included a simulated lesion on either the superolateral- or the inferomedial femoral neck. The hvFE model predictions of the stiffness (0.47 < R 2 < 0.94), failure load (0.77 < R 2 < 0.98), and exact fracture location (68%) were in good agreement with the experimental data. However, the model underestimated the failure load by a factor of two. The hvFE models predicted significant differences in stiffness and failure load for femora with superolateral- and inferomedial lesions. In contrast, standard clinical guidelines predicted identical fracture risk for both lesion sites. This study showed that the subject-specific QCT-based hvFE model could predict the effect of metastatic lesions on the biomechanical behaviour of the proximal femur with moderate computational time and high level of automation and could support treatment strategy in patients with metastatic bone disease.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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QCT-based finite element prediction of pathologic fractures in proximal femora with metastatic lesions

Benca

Synek

Amini

et al. 2019

Sci Rep

Self Cite

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“…27,28 Unfortunately, previous biomechanical studies of lytic lesions, as well as traumatic femur fractures, lack either control data on intact femurs or data on the residual weakness of fixated femurs compared with intact femurs. 13,15,20,21,29,30 Accordingly, we were unable to identify a comparison study reporting how much weaker a successfully fixated femur is expected to be than an intact femur in these settings.…”

Section: Discussionmentioning

confidence: 99%

Association of the Anterolateral Thigh Osteomyocutaneous Flap With Femur Structural Integrity and Assessment of Prophylactic Fixation

Worley

Patterson

Graboyes

et al. 2018

JAMA Otolaryngol Head Neck Surg

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IMPORTANCE The chimeric anterolateral thigh osteomyocutaneous (ALTO) free flap is a recently described microvascular option for head and neck osseous defects associated with complex soft-tissue requirements. To date, the association of ALTO flap harvest with femur structural integrity and the need for routine prophylactic fixation following harvest has been incompletely described. OBJECTIVE To investigate the association of ALTO flap harvest, with and without prophylactic fixation, on femur structural integrity as measured by 4-point bend and torsional biomechanical testing. DESIGN AND SETTING At a research laboratory, 24 synthetic fourth-generation composite femurs with validated biomechanical properties underwent 10-cm-long, 30% circumferential osteotomies at the proximal middle third of the femur; 6 femurs served as controls. Osteotomized femurs with and without fixation underwent torsional and 4-point bend biomechanical testing. Femur fixation consisted of intramedullary nail and distal interlock screw placement. MAIN OUTCOMES AND MEASURES Force and torque to fracture (expressed in kilonewtons [kN] and Newton meters [N·m], respectively) were compared between controls, osteotomized femurs without fixation, and osteotomized femurs with fixation. Additional outcome measures included femur stiffness and fracture patterns. RESULTS On posterior to anterior (PA) 4-point bend testing, force to fracture of osteotomized femurs was 22% of controls (mean difference, 8.3 kN; 95% CI, 6.6–10.0 kN). On torsional testing the torque to fracture of osteotomized femurs was 12% of controls (mean difference, 351.1 N·m; 95% CI, 307.1–395.1 N·m). Following fixation there was a 67% improvement in PA force to fracture and a 37% improvement in torque to fracture. However, osteotomized femurs with fixation continued to have a reduced PA force to fracture at 37% of controls (mean difference, 6.8 kN; 95% CI, 4.5–9.2 kN) and torque to fracture at 16% of controls (mean difference, 333.7 N·m; 95% CI, 306.8–360.6 N·m). On torsional testing, all osteotomized femurs developed similar spiral fractures through a corner of the distal osteotomy site. This fracture pattern changed after prophylactic fixation with femurs developing nondisplaced fractures through the proximal osteotomy site. There were no underlying hardware failures during testing of osteotomized femurs with fixation. CONCLUSIONS AND RELEVANCE Anterolateral thigh osteomyocutaneous flap harvest results in significant changes in the structural integrity of the femur. Postoperative stabilization should be strongly considered, with future research directed at investigating the clinical significance of residual biomechanical changes following femur fixation.

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“…Many believe these pathologic fractures begin the end-of-life cascade in patients with metastatic disease. CT remains the mainstay for that assessment (9). But perhaps in the near future, MRI techniques such as susceptibility-weighted MRI, ultrashort and/or zero echo time imaging, or susceptibility tensor imaging may obviate that risk assessment.…”

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confidence: 99%

Can Susceptibility-weighted MRI Help Differentiate Osteolytic from Osteoblastic Spine Metastases?

Schweitzer

2019

Radiology

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N early everything has changed in radiology since I was a resident 30 years ago. As a musculoskeletal radiologist, I believe MRI has had much to do with this revolution. The article by Böker and colleagues in this issue of Radiology (1) led me to remember that there have been at least two relative constants. First, metastatic disease is overwhelmingly the most common malignant tumor of bone. Second, osseous metastases are still generally classified as osteoblastic versus osteolytic. The fact that an MRI article brought these to consciousness is somewhat ironic.There are 350 000 cases of osseous metastatic disease in the United States each year (2). Notably, this number is growing due to improved premortem diagnosis and the therapeutic model of cancer becoming more often the management of a chronic disease (3). Because osseous metastatic disease presents less of a systemic burden than brain, hepatic, or pulmonary metastases, there is a greater focus on longitudinal assessment of osseous metastases.Thirty years after I trained, we continue to use the osteolytic versus osteoblastic classification schema. Osteolytic metastases are much more common and often occur with lung, gastrointestinal (usually colon), renal, and thyroid primary tumors. Osteoblastic metastases tend to occur with prostate and breast primary tumors (4). Mixed patterns are less common, and, in my opinion, are often the result of a patient's immune response to initial lytic tumors or lytic tumors that were treated. The latter is increasingly important as more patients with metastatic disease are being treated. Once upon a time, patients with metastatic disease were only treated palliatively; now, aggressive treatments are often pursued. Nearly all of these treatments become ineffective at some point in time and then the regimen must be changed. Continued follow-up with consideration for healing versus growth becomes necessary. By and large, this follow-up is gradually transitioning to the wholebody MRI detection of bone marrow. Because the bulk of osseous metastatic disease is in the axial skeleton, focused advanced imaging of the spine is now common.Even today, the differentiation of osteolytic from osteoblastic metastases remains important. First, it helps ascertain the risk of pathologic fracture: Osteoblastic metastases tend to fracture less frequently but more transversely compared with osteolytic metastases. Second, in these often chronically burdened patients, the differentiation of osteolytic from osteoblastic metastases helps determine if their widespread disease is getting better or worse.Although we often look for the development of fat on MR images as a sign of healing, whether visually or with in-and out-of-phase imaging and/or the Dixon technique, sclerosis is another common way that osseous metastases heal. Hence, the precise assessment of an osteoblastic response remains vital.Metastases appear as a replacement of the normally predominantly fatty marrow, as was confirmed in the study by Böker et al. Edema is common but may be subtle ...

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Effect of simulated metastatic lesions on the biomechanical behavior of the proximal femur

Cited by 30 publications

References 35 publications

QCT-based finite element prediction of pathologic fractures in proximal femora with metastatic lesions

QCT-based finite element prediction of pathologic fractures in proximal femora with metastatic lesions

Association of the Anterolateral Thigh Osteomyocutaneous Flap With Femur Structural Integrity and Assessment of Prophylactic Fixation

Can Susceptibility-weighted MRI Help Differentiate Osteolytic from Osteoblastic Spine Metastases?

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