Biomechanical model of a high risk impending pathologic fracture of the femur: Lesion creation based on clinically implemented scoring systems

Alexander, Gerald; Gutiérrez, Sergio; Nayak, Aniruddh N.; Palumbo, Brian T.; Cheong, David; Letson, G. Douglas; Santoni, Brandon G.

doi:10.1016/j.clinbiomech.2013.02.011

Cited by 16 publications

(14 citation statements)

References 27 publications

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“…Second, the study was performed in vitro, on a limited number of specimens, with artificially created lesions, and only one defined lesion geometry was examined at two different sites. With 16 pairs, this was, to our best knowledge, the largest study ever conducted on mechanical properties of femora with simulated or real metastatic lesions, The simulated lesions do not exactly represent metastatic geometries occurring in clinical routine since metastatic lesions often affect multiple bone regions and its cortex by spreading from the bone marrow. Also, determining the failure load in a simulated one‐legged stance setup cannot be representative for all real life fracture mechanisms which are inherently different from one patient to another with different pathologies and load inductions.…”

Section: Discussionmentioning

confidence: 99%

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

Benca

Reisinger

Patsch

et al. 2017

Journal Orthopaedic Research

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Pathologic fractures of femora in patients with metastatic cancer are associated with high morbidity and mortality. Prediction of impending fractures is based on unspecific clinical criteria or past clinician's experience, which leads to underestimation or overtreatment. The aim of this study was to investigate the effect of the site of metastatic lesions on biomechanical behavior of the proximal femur. Sixteen pairs of human femora were scanned with quantitative computed tomography (QCT) to asses bone mineral density. One femur of each pair remained intact while a defined lesion was reamed out in either the superolateral or inferomedial portion of the femoral neck of the contralateral femur. All femora were loaded in a mechanical test setup mimicking one-legged stance and stiffness, failure load, and fracture location were determined. In the biomechanical experiments the superolateral lesion and the inferomedial lesion caused a stiffness reduction of 19% and 66%, respectively. The average failure load was 40% and 75% lower for specimens with the superolateral (4.53 ± 1.56 kN) and inferomedial (1.89 ± 1.73 kN) lesions, respectively, compared to intact specimens (7.66 ± 3.34 kN). Lesions in the femoral neck led to reduction in both stiffness and failure load of the proximal femur. Furthermore, the site of the lesion had a large effect on the magnitude of the reduction in biomechanical properties. The presented data emphasize the importance of differentiating between locations of the lesion in pathologic fracture prediction of the metastatic femur and underline the insufficient accuracy of current predictive guidelines. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2407-2414, 2017.

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Section: Discussionmentioning

confidence: 99%

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

Benca

Reisinger

Patsch

et al. 2017

Journal Orthopaedic Research

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“…It is believed by some scholars that there is no association between the preoperative bone fracture and the size of the tumorous lesions (Hirn et al, 2009;Keene, Sellinger, McBeath, & Engber, 1986). In the established 3D model of the bone defects, certain factors, such as notch (Dabiri & Li, 2015;Elias, Frassica, & Chao, 2000), segments (Chen et al, 2014;Duda et al, 2002), circular type (Alexander et al, 2013), and cylindrical type (Karunratanakul et al, 2013;Rennick et al, 2013), are considered. Because of the differences in these factors that have been found, it is difficult to compare the findings of finite element studies regarding fracture risk due to defect level, shape, and load, along with various other reasons (Liu et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Assessment of fracture risk in proximal tibia with tumorous bone defects by a finite element method

Lin

Zhu

et al. 2017

Microsc Res Tech

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There has not been a satisfying method to predict the fracture risk in tumorous bone lesions. To tackle this challenge, we used a finite element method to assess the fracture risk in the proximal tibia (pT) when the size and location of the tumorous defects are varied in bone. Towards this end, the circular cortical defects, mimicking the tumorous lesions by forming cortical window defects, with a diameter (Ф) of 20, 30, 40, or 50 mm, are structured on the anteromedial, lateral, posterior wall of pT, which is located 5, 15, and 25 mm below articular margin, respectively. We found that under walking conditions, the Von Mises Stress of each defective tibia model was larger than that of the intact tibia model and also showed a positive linear correlation with the sizes of the defects. A notable fracture risk was not observed until the defect was Ф30 mm or larger. When the defect emerged, the anteromedial wall resisted fracture risk more than the rest of wall. Our results show that the size and location of the bone tumors are important factors affecting the fracture risk of pT. Our findings will be beneficial to clinicians when deciding what treatment to use for pT lesions.

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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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Biomechanical model of a high risk impending pathologic fracture of the femur: Lesion creation based on clinically implemented scoring systems

Cited by 16 publications

References 27 publications

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

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

Assessment of fracture risk in proximal tibia with tumorous bone defects by a finite element method

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

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