John A Szivek

Interests

Research

Orthopaedic Biomaterials and Biomechanics -3D printing - Free Form Fabrication - Additive manufacturing -Pluripotent cell extraction, differentiation and utilization in tissue engineering -In vivo sensor and telemetry development for load measurement

Teaching

Bioengineering - Orthopaedic Biomaterials and Biomechanics -Orthopaedic Tissue Engineering - 3D Printing of Scaffolds and Cell Extraction and Utilization in Tissue Engineering - Implantable load sensor and Telemetry development

Courses

Scholarly Contributions

Chapters

• Szivek, J. A. (2008). Resorbable Polymer-Ceramic Composites for Orthopedic Scaffold Applications. In 28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4.
• Szivek, J. A., Vaidyanathan, R., Hecht, B., Studley, A., Phillips, T., Calvert, P. D., Tellis, B., & Coleman, A. (2008). Resorbable Polymer‐Ceramic Composites for Orthopedic Scaffold Applications. In 28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science(pp 529-536). doi:DOI:10.1002/9780470291191.ch80
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  Resorbable Polymer‐Ceramic Composites for Orthopedic Scaffold Applications
• Szivek, J. A. (1999). Synthetic Materials and Structures Used as Models for Bone. In Mechanical Testing of Bone and the Bone-Implant Interface(pp 159-171).
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  Synthetic Materials and Structures Used as Models for Bone
• Szivek, J. A. (1999). Synthetic materials and structures used as models for bone. In Mechanical Testing of Bone and the Bone-Implant Interface(pp 159-171). CRC Press.
• Szivek, J. A., & Gharpuray, V. M. (1999). Strain Gauge Measurements from Bone Surfaces. In Mechanical Testing of Bone and the Bone-Implant Interface(pp 305-320).
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  Mechanical Testing of Bone and the Bone-Implant Interface

Journals/Publications

• Szivek, J. A., & Karl, W. H. (2021). Repair and remodeling of partial-weightbearing, uninstrumented long bone fracture model in mice treated with low intensisty vibration therapy. Clinical Biomechanics, 81.
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  Repair and remodeling of partial-weightbearing, uninstrumented long bone fracture model in mice treated with low intensity vibration therapy
• Szivek, J. A. (2019). A Purification Technique for Adipose-Derived Stromal Cell Cultures Leads to a More Regenerative Cell Population. Journal of Investigative Surgery.
• Szivek, J. A. (2019). Mesenchymal stem cell seeded, biomimetic 3D printed scaffolds induce complete bridging of femoral critical sized defects. Journal of Biomedical Materials Research Part B: Applied Biomaterials.
• Conway, R. F., Okarski, K. M., & Szivek, J. A. (2018). A Purification Technique for Adipose-Derived Stromal Cell Cultures Leads to a More Regenerative Cell Population. J Investigative Surgery. doi:DOI:10.1080/08941939.2017.1423420
• Szivek, J. A., Gonzales, D. A., Wojtanowski, A. M., Martinez, M. A., & Smith, J. L. (2018). Mesenchymal stem cell seeded, biomimetic 3D printed scaffolds induce complete bridging of femoral critical sized defects. Journal of biomedical materials research. Part B, Applied biomaterials.
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  No current clinical treatments provide an ideal long-term solution for repair of long bone segment defects. Incomplete healing prevents patients from returning to preinjury activity and ultimately requires additional surgery to induce healing. Obtaining autologous graft material is costly, incurs morbidity, requires surgical time, and quality material is finite. In this pilot study, 3D printed biomimetic scaffolds were used to facilitate rapid bone bridging in critical sized defects in a sheep model. An inverse trabecular pattern based on micro-CT scans of sheep trabecular bone was printed in polybutylene terephthalate. Scaffolds were coated with micron-sized tricalcium phosphate particles to induce osteoconductivity. Mesenchymal stem cells (MSCs) were isolated from sheep inguinal and tail fat, in one group of sheep and scaffolds were infiltrated with MSCs in a bioreactor. Controls did not undergo surgery for cell extraction. Scaffolds were implanted into two experimental and two control adult sheep, and followed for either 3 or 6 months. Monthly radiographs and post explant micro-CT scanning demonstrated bone formation on the lateral, anterior, medial, and posterior-medial aspects along the entire length of the defect. Bone formation was absent on the posterior-lateral aspect where a muscle is generally attached to the bone. The 3-month time point showed 15.5% more cortical bone deposition around the scaffold circumference while the 6-month time point showed 40.9% more bone deposition within scaffold pores. Control sheep failed to unite. Serum collagen type-1C-terminus telopeptides (CTX-1) showed time-dependent levels of bone resorption, and calcein labeling demonstrated an increase in bone formation rate in treated animals compared with controls. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018.
• Szivek, J. A. (2017). Determination of joint loads using new sensate scaffolds for regenerating large cartilage defects in the knee. Journal of Biomedical Materials Research Part B: Applied Biomaterials.
• Szivek, J. A., Ruth, J. T., Heden, G. J., Martinez, M. A., Diggins, N. H., & Wenger, K. H. (2017). Determination of joint loads using new sensate scaffolds for regenerating large cartilage defects in the knee. Journal of biomedical materials research. Part B, Applied biomaterials, 105(6), 1409-1421.
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  Two complete unicondylar surface replacement scaffold designs to support tissue-engineered cartilage growth that utilized adult endogenous stem cells were 3D printed and tested in a dog stifle model. Integrated rosette strain gauges were calibrated and used to determine shear loading within stifle joints for up to 12 months. An activity index that compared extent of daily activity with tissue formation showed differences in the extent and quality of new tissue with the most active animal having the most new tissue formation. Shear loads were highest early and decreased with time indicating that cartilage tissue formation begins while tissues experience high shear loads and continues as the loads decrease toward normal physiological levels. Scaffolds with biomimetic support pegs facilitated the most rapid bone ingrowth and were noted to have more cartilage formation with better quality cartilage as measured using both indentation testing and histology. Comparison of implant placement depth to previous studies suggested that placement depth affects the amount of tissue formation. This study provides measurements of loading patterns and cartilage regeneration on a complete medial condylar surface replacement that can be used for preclinical testing of a tissue engineering approach for the most common form of early stage osteoarthritis, unicondylar disease. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1409-1421, 2017.
• Ferng, A. S., Marsh, K. M., Fleming, J. M., Conway, R. F., Schipper, D., Bajaj, N., Connell, A. M., Pilikian, T., Johnson, K., Runyan, R., Black, S. M., Szivek, J. A., & Khalpey, Z. (2016). Adipose-derived human stem/stromal cells: comparative organ specific mitochondrial bioenergy profiles. SPRINGERPLUS, 5.
• Gao, L., Schmitz, H. A., Zuniga, A. A., Klewer, J. A., Szivek, J. A., Taljanovic, M. S., Latt, L. D., & Witte, R. S. (2016). Minimizing strain error for in vivo ultra-sound elasticity imaging of human tendon. 2016 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS).
• Szivek, J. A. (2016). Adipose-derived human stem/stromal cells: comparative organ specific mitochondrial bioenergy profiles. SpringerPlus.
• Gao, L., Yuan, J. S., Heden, G. J., Szivek, J. A., Taljanovic, M. S., Latt, L. D., & Witte, R. S. (2015). Ultrasound Elasticity Imaging for Determining the Mechanical Properties of Human Posterior Tibial Tendon: A Cadaveric Study. IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, 62(4), 1179-1184.
• Szivek, J. A. (2015). Ultrasound Elasticity Imaging for Determining the Mechanical Properties of Human Posterior Tibial Tendon: A Cadaveric Study. IEEE Transactions on Biomedical Engineering.
• Szivek, J. A. (2014). In vivo telemetric determination of shear and axial loads on a regenerative cartilage scaffold following ligament disruption. Journal of Biomedical Materials Research Part B: Applied Biomaterials.
• Szivek, J. A. (2013). Co-culture of adipose derived stem cells and chondrocytes with surface modifying proteins induces enhanced cartilage tissue formation. Journal of Investigative Surgery.
• Waters, H. A., Geffre, C. P., Gonzales, D. A., Grana, W. A., & Szivek, J. A. (2013). Co-Culture of Adipose Derived Stem Cells and Chondrocytes with Surface Modifying Proteins Induces Enhanced Cartilage Tissue Formation. Journal of Investigative Surgery, 26(3), 118-126.
• Ledet, E. H., D'Lima, D., Westerhoff, P., Szivek, J. A., Wachs, R. A., & Bergmann, G. (2012). Implantable Sensor Technology: From Research to Clinical Practice. Journal of the American Academy of Orthopaedic Surgeons, 20(6), 383-392.
• Szivek, J. A. (2012). Implantable sensor technology: From research to clinical practice. Journal of the American Academy of Orthopaedic Surgeons.
• Szivek, J. A. (2011). Load-Bearing at the Meniscofemoral Joint: An in vitro Study in the Canine Knee. The Duke Orthopaedic Journal.
• Szivek, J. A. (2011). Mechanical loading of adipose derived stromal cells causes cell alignment. Journal of Biomedical Science and Engineering.
• Szivek, J. A. (2011). TU‐A‐220‐03: Ultrasound Elasticity Imaging of Human Posterior Tibial Tendon. Medical Physics.
• Szivek, J. A. (2010). Evaluation of the osteogenic performance of calcium phosphate-chitosan bone fillers. Journal of Investigative Surgery.
• Szivek, J. A. (2010). Load measurement accuracy from sensate scaffolds with and without a cartilage surface. Journal of Investigative Surgery.
• Szivek, J. A., Schnepp, A. B., Indelli, P. F., & Grana, W. A. (2010). Load-Bearing at the Meniscofemoral Joint: An in vitro Study in the Canine Knee. Clinical Rhinology An International Journal, 1(1), 39-43.
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  Background: The role of the menisci on tibial load transmission and stress distribution has been extensively studied, but few studieshave focused on the meniscofemoral joint during physiologic weightbearing. The objective of this study was to determine the contactareas and local contact stresses at the meniscofemoral interface during physiologic range of motion and axial-loading in the canine kneeand to determine the influence of a partial or total meniscectomy.Methods: Both fresh-frozen knees of 3 hound-type canines were tested in a universal testing machine configured for an axial-load of 90-120 N. Measurement of the contact area and the local contact stress were done at three different knee angles (30; 50; 70) and with bothmenisci intact, after partial meniscectomy, and after total meniscectomy. Pressure distribution was estimated by using pressure sensitivefilm inserted above the menisci.Results: After partial meniscectomy, contact areas at 50� of knee flexion decreased approximately 25% on both femoral condyles, andlocal contact stress increased 30% on the medial femoral condyle but remained unchanged on the lateral. After total meniscectomy,contact areas at 50� of knee flexion decreased approximately 75% on both femoral condyles, and local contact stress increasedapproximately 60% on the medial compartment and 100% on the lateral compartment.Conclusions: These data suggest that a conservative partial meniscectomy leaves the meniscus with an inferior weight distributionfunction; decreasing, but not canceling the protection on the femoral hyaline cartilage. A dramatic decrease of contact area followed byan increase of local contact stress was noted after a total meniscectomy. The clinical value of this study is to emphasize the biomechanicalvalue of surgical procedures addressing the repair of damaged menisci.
• Szivek, J. A. (2009). A novel biomimetic polymer scaffold design enhances bone ingrowth. Journal of Biomedical Materials Research Part A.
• Szivek, J. A. (2009). Trabecular scaffolds created using micro CT guided fused deposition modeling.. Materials science & engineering. C, Materials for biological applications.
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  Free form fabrication and high resolution imaging techniques enable the creation of biomimetic tissue engineering scaffolds. A 3D CAD model of canine trabecular bone was produced via micro CT and exported to a fused deposition modeler, to produce polybutylene terephthalate (PBT) trabeculated scaffolds and four other scaffold groups of varying pore structures. The five scaffold groups were divided into subgroups (n=6) and compression tested at two load rates (49 N/s and 294 N/s). Two groups were soaked in a 25 °C saline solution for 7 days before compression testing. Micro CT was used to compare porosity, connectivity density, and trabecular separation of each scaffold type to a canine trabecular bone sample. At 49 N/s the dry trabecular scaffolds had a compressive stiffness of 4.94±1.19 MPa, similar to the simple linear small pore scaffolds and significantly more stiff (p
• Szivek, J. A., Montague, M. D., Geffre, C. P., & Gainer, C. F. (2009). A Biomimetic Sensate Scaffold Measures Loading in a Knee Joint. J of Investigative Medicine, 57(1), 225-226.
• Ferng, A. S., Ferguson, C. W., & Szivek, J. A. (2008). Inducing Cartilage Regeneration with Stem Cells for Treatment of Osteoarthritis Patients. FASEB JOURNAL, 22.
• Geffre, C. P., Bliss, C. L., Szivek, J. A., DeYoung, D. W., Ruth, J. T., & Margolis, D. S. (2008). Sensate scaffolds coupled to telemetry can monitor In Vivo loading from within a joint over extended periods of time. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS, 84B(1), 263-270.
• Szivek, J. A. (2008). A handheld computer as part of a portable in vivo knee joint load-monitoring system. Journal of Medical Devices, Transactions of the ASME.
• Szivek, J. A. (2008). Phenotypic characteristics of bone in carbonic anhydrase II-deficient mice. Calcified Tissue International.
• Szivek, J. A. (2008). Sensate scaffolds coupled to telemetry can monitor in vivo loading from within a joint over extended periods of time. Journal of Biomedical Materials Research - Part B Applied Biomaterials.
• Szivek, J. A., Geffre, C. P., & Margolis, D. S. (2008). Comparison of Bone Ingrowth into Scaffolds with Simple and Novel Biomimetic Porous Architectures. Journal of Investigative Medicine, Supplement, 56(1), 242.
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  Comparison of Bone Ingrowth into Scaffolds with Simple and Novel Biomimetic Porous Architectures
• Szivek, J. A., Manson, P., & Webber, N. (2008). Scanning and Characterization of Human Scaffolds for Cartilage Tissue Engineering. Journal of Investigative Medicine - Supplement, 56(1), 327.
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  Scanning and Characterization of Human Scaffolds for Cartilage Tissue Engineering
• Szivek, J. A., Margolis, D. S., Geffre, C. P., Lai, L., & Lien, Y. H. (2008). CPC Coated Strain Gauges can Monitor In Vivo Bone Strain in a Mouse. Journal of Investigative Surgery- Supplement, 56(1), 327.
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  CPC Coated Strain Gauges can Monitor In Vivo Bone Strain in a Mouse
• Szivek, J. A. (2007). Selective cell proliferation can be controlled with CPC particle coatings. Journal of Biomedical Materials Research - Part A.
• Szivek, J. A. (2007). Sensate scaffolds can reliably detect joint loading. Journal of Biomedical Materials Research - Part B Applied Biomaterials.
• Grana, W. A., Szivek, J. A., Schnepp, A. B., & Ramos, R. (2006). A comparison of the effects of radiofrequency treatment and mechanical shaving for meniscectomy. ARTHROSCOPY-THE JOURNAL OF ARTHROSCOPIC AND RELATED SURGERY, 22(8), 884-888.
• Margolis, D. S., Kim, D., Szivek, J. A., Lai, L., & Lien, Y. H. (2006). Functionally improved bone in Calbindin-D28k knockout mice. BONE, 39(3), 477-484.
• Ruth, J. T., Vaidyanathan, R. K., Tellis, B. C., Szivek, J. A., Schnepp, A. B., Ruth, J. T., Margolis, D. S., Geffre, C. P., Deyoung, D. W., & Bliss, C. L. (2006). 213 POROUS POLYBUTYLENE TEREPHTHALATE IMPLANTS ALLOW FOR BONE INGROWTH AND PROVIDE A WELL-ANCHORED SCAFFOLD THAT CAN BE USED TO DELIVER TISSUE-ENGINEERED CARTILAGE.. Journal of Investigative Medicine, 54(1), S116.5-S116. doi:10.2310/6650.2005.x0004.212
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  While joint pain and loss of mobility are common causes of impairment, there are few procedures that can consistently restore the long-term function of damaged articular cartilage. One approach that offers a potential solution for articular cartilage repair is replacement of the damaged cartilage using a tissue-engineered scaffold. The goal of this study was to measure loading and bone attachment in sensate, porous, calcium phosphate ceramic (CPC) coated polybutylene terephthalate (PBT) scaffolds that have been implanted in the medial compartment of the knees of 6 canines. In addition histology, histomorphometry, and scanning electron microscopy (SEM) were used to characterize bone growth into and around the PBT scaffold. In vivo measurements from the calibrated scaffolds indicated that peak loads in the dog knees ranged from 80-120N. Post-sacrifice biomechanical testing indicated that these loads correlated to pressures of 11 ± 1.54 MPa in the medial compartment of the knees. Histology demonstrated a bone volume of 6.8 ± 8.8% within the scaffold pores and an osteoid volume of 64.9 ± 17.2%. Histomorphometry indicated an increased bone formation rate within the scaffold pores, 8.2E-5 ± 5.9E-5 μm3 /μm2 /day, compared to 1.3E-5 ± 0.8E-5 mm3 /μm2 /day in control knees. SEM demonstrated less bone within the scaffold pores compared to the extensive amount of bone surrounding the scaffold and in intimate contact with the CPC particles. These results demonstrate that the scaffold is mechanically coupled to the bone. In addition, the increased bone formation rate and osteoid within the PBT pores demonstrate that bone formation is still occurring 6 months post-op. Currently studies are focused on the integration of PBT scaffolds containing a tissue-engineered cartilage covering into damaged articular cartilage.
• Szivek, J. A. (2006). A Comparison of the Effects of Radiofrequency Treatment and Mechanical Shaving for Meniscectomy. Arthroscopy - Journal of Arthroscopic and Related Surgery.
• Szivek, J. A. (2006). An instrumented scaffold can monitor loading in the knee joint. Journal of Biomedical Materials Research - Part B Applied Biomaterials.
• Szivek, J. A. (2006). Functionally improved bone in Calbindin-D28k knockout mice. Bone.
• Szivek, J. A., Bliss, C. L., Geffre, C. P., Margolis, D. S., DeYoung, D. W., Ruth, J. T., Schnepp, A. B., Tellis, B. C., & Vaidyanathan, R. K. (2006). An instrumented scaffold can monitor loading in the knee joint. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS, 79B(2), 218-228.
• Szivek, J. A., Davis, J., & Bliss, C. (2006). 198 OPTICAL COHERENCE TOMOGRAPHY DEVELOPMENT AND USE TO IDENTIFY ARTICULAR CARTILAGE TISSUE AND CELL STRATIFICATION.. Journal of Investigative Medicine, 54(1), S114.2-S114. doi:10.2310/6650.2005.x0004.197
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  Osteoarthritis (OA), or degenerative joint disease, burdens approximately 40 million people in the US and is one of the most disabling conditions in developed nations. Recent studies have shown that surgical interventions such as autologous chondrocyte implantation and osteochondral cylinder transplantation (mosaicplasty) have been successful in reducing the pain caused by OA; however, with autologus chondrocyte implantation the defect ultimately is filled with fibrocartilage rather than the native hyaline articulating cartilage. Furthermore, with mosaicplasty, a number of patients often complain of painful disturbances at the graft site due to the donor site morbidity associated with larger defects (Horas et al 2003, Hangody et al 2003). The potential use of an engineered articular cartilage grown in cell culture to resurface the defect caused by OA is the ideal treatment when compared with filling the defect with a mechanically unfit form of cartilage or causing damage to an otherwise healthy donor site. As better techniques to stratify and orient engineered cartilaginous tissue layers become available it will be valuable to use a high resolution, nondestructive imaging technique to monitor growth and therapeutic effectiveness of the engineered construct. Optical coherence tomography (OCT) has shown potential as a method of high resolution (4-15 μm), non-invasive intraarticular cartilage imaging (Drexler et al 2001, Herrmann et al 1999). OCT is analogous to ultrasound in that it measures the intensity of back-reflected light rather than sound waves. We used OCT to characterize the femoral articulating cartilage of canines obtained post-limb amputation. After OCT imaging, the articulating surfaces were sectioned and stained for a histological evaluation. The OCT images were then compared to their corresponding histology, using non-polarized and polarized light microscopy, in order to evaluate the usefulness and structural clarity of the images. In the OCT images we were able to identify the superficial layer of the articular cartilage, the cartilage-bone interface, and the cartilage thickness. We conclude that OCT does in fact provide enough structural information to monitor growth and therapeutic effectiveness of an engineered cartilage model. In the future we hope to use polarization sensitive OCT to further characterize articular cartilage and identify the middle and deep layers. Once characterization of native cartilage is complete this technique will be implemented on engineered cartilaginous cells and tissue grown in culture to determine whether layer formation occurs.
• Szivek, J. A., Davis, J., & Bliss, C. (2006). Optical coherence tomography development and use to identify articular cartilage tissue and cell stratification. Journal of Investigative Medicine - 198 Supplement, 54(1), S114-S114.
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  Optical coherence tomography development and use to identify articular cartilage tissue and cell stratification
• Szivek, J. A., Margolis, D. S., Bliss, C. L., Geffre, C. P., DeYoung, D. W., Ruth, J. T., Tellis, B. C., Vaidyanathan, R. K., & Schnepp, A. B. (2006). Porous polybutylene terephthalate implants allow for bone ingrowth and provide a well-anchored scaffold that can be used to deliver tissue-engineered cartilage. Journal of Investigative Medicine, 213 Supplement, 54(1), S116-S116.
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  Porous polybutylene terephthalate implants allow for bone ingrowth and provide a well-anchored scaffold that can be used to deliver tissue-engineered cartilage
• Szivek, J. A., Margolis, D. S., Pennington, D., Grana, W. A., Furenlid, L., Willson, D., Lia, L. W., & Lien, Y. H. (2006). In vivo strain gauge attachment to mouse femora. Journal of Investigative Medicine - 212 Suppl. S, 54(1), S116-S116.
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  In vivo strain gauge attachment to mouse femora
• Wilson, D., Szivek, J. A., Pennington, D., Margolis, D. S., Lien, Y. H., Lia, L. W., Grana, W. A., & Furenlid, L. (2006). 212 IN VIVO STRAIN GAUGE ATTACHMENT TO MOUSE FEMORA.. Journal of Investigative Medicine, 54(1), S116.4-S116. doi:10.2310/6650.2005.x0004.211
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  Bone properties are dynamic and change due to physiologic strains generated during loading. Measurement of physiologic strains has been accomplished in dogs and rats with the use calcium phosphate ceramic (CPC) coated strain gauges. The purpose of this study was to determine whether TGF-β1 enhanced CPC coated strain gauges could be attached to mouse femora in vivo. Five mice were implanted with CPC-2 coated uniaxial, single element strain gauges (Vishay Micro measurements, NC) that were enhanced with 0.25 μg of TGF-β1 8 hours before surgery. One strain gauge was implanted in each mouse, and the gauges were initially secured to the right femur of each mouse using 2 resorbable sutures. The mice were sacrifice 8 weeks postop. Following sacrifice the mechanical attachment of the implanted gauges was measured using a cantilever bend test. The bone bonding and bone to CPC contact was evaluated using high resolution μCT and histology. Bone formation rate was measured using CT/SPECT imaging and histomorphometry. Cantilever bend testing indicated that strain transfer through the CPC coated gauges was 51 ± 16% of strain measured in a control gauge glued to the contralateral femora. High resolution μCT and histology demonstrated extensive contact between the bone and CPC particles. Although there was an increased amount of bone in the experimental femora, this did not result in a significant increase in bone volume (46±6% in experimental femora and 47 ± 4% in control femora). SPECT imaging demonstrated increased bone formation on the experimental femur near the implanted sensors. Histomorphometry confirmed the increased BFR (0.0022 ± 0.0011 μm 3 /μm 2 /day in experimental femora and 0.0006 ± 0.0002 μm 3 /μm 2 /day in control femora) and demonstrated that the increase was due to an increased mineral apposition rate (0.0022 ± 0.0007 μm/day in experimental femora and 0.0010 ± 0.0002 μm/day in control femora). These results indicate extensive bone to CPC bonding occurs in mice implanted with CPC coated strain gauges. The use of in vivo bone strain gauging will be a valuable tool to study strain mediated bone remodeling in mice. In addition this technique allows for investigation of the magnitudes and roles of physiologic bone strains generated in gene knockout mice.
• Szivek, J. A. (2005). In vivo strain measurements from hardware and lamina during spine fusion. Journal of Biomedical Materials Research - Part B Applied Biomaterials.
• Szivek, J. A. (2005). TGF-β1-enhanced TCP-coated sensate scaffolds can detect bone bonding. Journal of Biomedical Materials Research - Part B Applied Biomaterials.
• Szivek, J. A., Roberto, R. F., & Margolis, D. S. (2005). In vivo strain measurements from hardware and lamina during spine fusion. Journal of biomedical materials research. Part B, Applied biomaterials, 75(2), 243-50.
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  Currently, spine fusion is determined using radiography and clinical evaluation. There are discrepancies between radiographic evidence and direct measurements of fusion, such as operative exploration and biomechanical or histological measurements. In order to facilitate the rapid return of patients to normal activities, a monitoring technique to accurately detect fusion in vivo and to prevent overload during the postoperative period would be useful. The objectives of this study were to develop an implantable monitoring system consisting of CPC-coated strain gauges and a radio transmitter to detect the onset of fusion and measure strain during postsurgical activities. A patient underwent anterior release and fusion, followed by posterior instrumentation and fusion with segmental spinal instrumentation. Four strain gauges were placed during surgery. One was attached to the left-side rod and one to each of the lamina at T9, T10, and T11. An externally powered implanted radio transmitter attached to the gauges was placed in a subcutaneous pouch. Strains were monitored weekly and tabulated during various activities for 7 months. Peak strains during twisting and bending were tabulated to detect the onset of fusion. Strains were also recorded during activities such as climbing off an examination table, rising from a chair, and climbing stairs. Strains collected from the left rod indicated that, immediately postoperatively, it was loaded at acceptable levels. The largest and most consistent strain changes measured from the lamina were recorded during twisting.
• Szivek, J. A. (2004). Bilateral symmetry of biomechanical properties in mouse femora. Medical Engineering and Physics.
• Szivek, J. A. (2004). Transforming growth factor-β1 accelerates bone bonding to a blended calcium phosphate ceramic coating: A dose-response study. Journal of Biomedical Materials Research - Part A.
• Szivek, J. A., Indelli, P. F., Schnepp, A., & Grana, W. A. (2004). Load bearing at the menisco-femoral joint: an in vitro study in the canine knee. Arthroscopy, 20(S1), S22, e10.
• Szivek, J. A., Indelli, P., Vestri, R., Schnepp, A., & Grana, W. A. (2004). Distribucion de las cargas en los condilos femorales de la rodilla: estudio biomecanico en perros. Rev. Argent. Arthroscopy, 11(1), 54-58.
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  Load distribution in knee femoral condyles: biomechanical study in dogs
• Szivek, J. A., Margolis, D. S., Kim, D., Lai, L., Kastis, G., & Lien, Y. H. (2004). Decreased osteoblast activity in carbonic anhydrase II deficient mice causes osteoporotic bone. Journal of Investigative Surgery, 52(1), S80-S80.
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  Decreased osteoblast activity in carbonic anhydrase II deficient mice causes osteoporotic bone
• Szivek, J. A., Margolis, D. S., Lien, Y. H., Lai, L. W., Kim, D., & Kastis, G. A. (2004). 8 DECREASED OSTEOBLAST ACTIVITY IN CARBONIC ANHYDRASE II DEFICIENT MICE CAUSES OSTEOPOROTIC BONE. Journal of Investigative Medicine, 52(Suppl 1), S80.3-S80. doi:10.1136/jim-52-suppl1-08
• Szivek, J. A., Nelson, E. R., Hajdu, S. D., Yablonski, K., & DeYoung, D. W. (2004). Transforming growth factor-beta1 accelerates bone bonding to a blended calcium phosphate ceramic coating: a dose-response study. Journal of biomedical materials research. Part A, 68(3), 537-43.
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  In vivo strain measurements can facilitate the study of the bone remodeling response to loading and load changes. Calcium phosphate ceramic (CPC) coatings have been used to attach strain gauges to bone for extended periods of time, but require up to 12 weeks for adequate CPC-to-bone bonding. Transforming growth factor beta 1 (TGF-beta1), an osteoinductive growth factor, was used as a surface enhancement to accelerate bone growth and bonding to CPC particles. The aim of this study was to find an optimal dosage of TGF-beta1 to accelerate the attachment process. CPC-coated strain gauges were enhanced with doses of 0.5, 1.0, or 2.0 microg of TGF-beta1 per gauge. Gauges were placed on the femora of dogs, which were exercised daily and fed ad libitum. After 3, 6, and 12 weeks, gauge attachment was quantitatively assessed using mechanical testing and histomorphometry. Gauge attachment was also qualitatively assessed using back scatter electron microscopy. Agreement of the mechanical test results with both the back scatter electron microscopy images and histomorphometry results showed that the 1.0 microg per gauge dose of TGF-beta1 is an optimal dose to accelerate bone formation and attachment to CPC-coated strain gauges.
• Szivek, J., Margolis, D. S., Lien, Y. H., Lai, L., & Szivek, J. A. (2004). Bilateral symmetry of biomechanical properties in mouse femora. Medical engineering & physics, 26(4).
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  Bone healing and remodeling are commonly examined in animal models by comparing one femur (experimental) to the contralateral femur (control) with the assumption that they are identical with respect to their biomechanical properties. While past studies have characterized the symmetry in geometrical properties in many types of animal bones, few studies have compared the symmetry in the biomechanical properties. The purpose of this study was to determine whether there is symmetry in the mechanical properties of mouse femora. Strain gauges were attached to the posterior surface of the femora of C57BL/6 mice, parallel to the long axis of the bone. The femora were mechanically tested in cantilever bending while strain values were recorded. Moments of inertia, cortical areas, and moduli of elasticity were determined from strains and cross-sectional properties. Mouse femora demonstrated an average strain difference of 0.4% in tension and 1.4% in compression. Elastic moduli differed by 6.6% and 0.9% in tension and compression, respectively, and failure strength differed by an average of 2.0%. Statistical analysis showed there were no significant differences in strain, modulus, or failure load values for the mice, indicating mechanical and geometrical symmetry of mouse femora in cantilever bending.
• Fernandez, M. M., Szivek, J. A., & Margolis, D. S. (2003). Evaluation of a new CPC-to-gauge bonding technique with the use of in vitro fluid flow. Journal of biomedical materials research. Part B, Applied biomaterials, 66(2), 514-9.
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  Strain gauging enables the measurement of bone deformation during physical activity, leading to a better understanding of the physiological effects of loading on bone growth and remodeling. Development of a technology that will withstand long-term in vivo exposure and bond securely to bone is imperative for accurate, consistent measurement collection. Polysulfone is currently used to attach calcium-phosphate ceramic (CPC) particles, which promote bone-to-gauge bonding, to polyimide-backed strain gauges. This study evaluated the use of an implant-grade epoxy as an alternative CPC-polyimide adhesive. Polyimide-epoxy-CPC interfaces were loaded to failure and shear strengths calculated. In vitro studies providing a constant flow of medium over test specimens were designed, and long-term in vitro fluid exposure studies of the epoxy's shear strength were conducted. Average shear strength of polysulfone-polyimide interfaces were reported to be 7 MPa. The average shear strength of the epoxy-polyimide interface before long-term in vitro exposure was 17 MPa, which is stronger than the shear strength of the bone-CPC interface. The strength of the epoxy-polyimide interface decreased to 6.8 MPa after 24 weeks in vitro and 3 MPa after 24 weeks in vivo.
• Szivek, J. A. (2003). Evaluation of a New CPC-to-Gauge Bonding Technique with the Use of In Vitro Fluid Flow. Journal of Biomedical Materials Research - Part B Applied Biomaterials.
• Szivek, J. A. (2003). The effectof implant overlap on the mechanical properties of the femur. Journal of Trauma.
• Szivek, J. A., Margolis, D. S., & Dag, M. (2003). Preparation and Calibration of Sensate Scaffolds. Journal of Investigative Medicine - 248, 52(1), S381-S381.
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  Preparation and Testing of Sensate Scaffolds
• Szivek, J. A., Margolis, D. S., & Dag, M. (2003). Preparation and Testing of Sensate Scaffolds. Journal of Investigative Medicine - 248, 52(1), S51-S51.
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  Preparation and Testing of Sensate Scaffolds
• Szivek, J. A. (2002). An implantable strain measurement system designed to detect spine fusion: Preliminary results from a biomechanical in vivo study. Spine.
• Szivek, J. A., Roberto, R. F., Slack, J. M., & Majeed, B. S. (2002). An Implantable strain measurement system designed to detect spine fusion - Preliminary results from a biomechanical in vivo study. Spine, 27(5), 487-497.
• Szivek, J. A. (2001). Linear and volumetric wear of tibial inserts in posterior cruciate-retaining knee arthroplasties. Clinical Orthopaedics and Related Research.
• Szivek, J. A. (2001). Long-term measurement of bone strain in vivo: The rat tibia. Journal of Biomedical Materials Research.
• Szivek, J. A. (2001). Strain transfer between a CPC coated strain gauge and cortical bone during bending. Journal of Biomedical Materials Research.
• Szivek, J. A. (2001). Surface enhancements accelerate bone bonding to CPC-coated strain gauges. Journal of Biomedical Materials Research.
• Szivek, J. A. (2000). A comparison of in vitro and in vivo degradation of two CPC strain gauge coatings. Journal of Biomedical Materials Research.
• Szivek, J. A. (2000). An experimental method for the application of lateral muscle loading and its effect on femoral strain distributions. Medical Engineering and Physics.
• Szivek, J. A., Price, A. C., & Roberto, R. F. (2000). Development of a measurement technique for in vivo monitoring of spinal fusion in scoliosis patients. Journal of Investigative Medicine - Supplement, 48(1), 331 S.
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  Development of a measurement technique for in vivo monitoring of spinal fusion in scoliosis patients
• Szivek, J. A. (1999). Bone bonding strength of calcium phosphate ceramic coated strain gauges. Journal of Biomedical Materials Research.
• Szivek, J. A. (1999). Development of a knee telemetry data capture and feedback system. Journal of Investigative Medicine.
• Szivek, J. A. (1999). Polyethylene particle morphology in synovial fluid of failed knee arthroplasty. Clinical Orthopaedics and Related Research.
• Szivek, J. A. (1999). Volumetric wear analysis of polyethylene tibial inserts in artificial knees. Journal of Investigative Medicine.
• Szivek, J. A., Rabkin, B. A., Schonfeld, J., & Halloran, B. P. (1999). An in-vivo model for long term assessment of bone strains. Journal of Investigative Medicine - Supplement 1, 14, SA029.
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  An in-vivo model for long term assessment of bone strains
• Szivek, J. A. (1998). A mechanical and histomorphometric analysis of bone bonding by hydroxyapatite-coated strain gages. Journal of Investigative Surgery.
• Szivek, J. A. (1998). Contact areas and pressures between native patellas and prosthetic femoral components. Journal of Arthroplasty.
• Szivek, J. A. (1998). Interface strength studies of calcium phosphate ceramic coated strain gauges. Journal of Biomedical Materials Research.
• Szivek, J. A. (1997). Erratum: Average and peak contact stress distribution evaluation of total knee arthroplasties (Journal of Arthroplasty (December 1996) 11 (952- 963)). Journal of Arthroplasty.
• Szivek, J. A. (1997). In vivo strain measurements collected using calcium phosphate ceramic-bonded strain gauges. Journal of Investigative Surgery.
• Szivek, J. A. (1997). Pullout strengths of cannulated and noncannulated cancellous bone screws. Clinical Orthopaedics and Related Research.
• Szivek, J. A. (1997). The ability of various acetabular components to resist protrusio migration. Orthopedics.
• Szivek, J. A. (1996). Average and peak contact stress distribution evaluation of total knee arthroplasties. Journal of Arthroplasty.
• Szivek, J. A. (1996). Bilateral symmetry of biomechanical properties in rat femora. Journal of Biomedical Materials Research.
• Szivek, J. A. (1996). Evaluation of factors affecting bonding rate of calcium phosphate ceramic coatings for in vivo strain gauge attachment. Journal of Biomedical Materials Research.
• Szivek, J. A., Anderson, P. L., & Benjamin, J. B. (1996). Average and peak contact stress distribution evaluation of total knee arthroplasties. Journal of Arthroplasty, 11(8), 952-963.
• Szivek, J. A., Anderson, P. L., Dishongh, T. J., & DeYoung, D. W. (1996). Evaluation of factors affecting bonding rate of calcium phosphate ceramic coatings for in vivo strain gauge attachment. Journal of Biomedical Materials Research, 33(3), 121-132.
• Szivek, J., Szivek, J. A., Battraw, G. A., Miera, V., & Anderson, P. L. (1996). Bilateral symmetry of biomechanical properties in rat femora. Journal of Biomedical Materials Research, 32(2).
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  In many studies, bone healing and remodeling have been examined in various animal models using one femur as a control for the contralateral femur based on the assumption that they are bilaterally symmetrical. Symmetry studies have been limited mainly to geometrical properties. The purpose of this study was to determine whether or not there is symmetry in the mechanical properties of rat femora. Two strain gauges were attached to the anterior surface parallel to the long axis of explanted femora of retired female breeder and 120-day-old male Sprague Dawley rats. Femora were mechanically tested in cantilever bending and the strain values were recorded. Moments of inertia, cortical areas, and moduli of elasticity were determined from strains and cross-sectional properties. Female femora showed a bilateral strain difference of less than 2.2% and an elastic modulus difference of less than 8.7%. Males had less than 2.0% and 7.9% differences for strain and elastic moduli, respectively. Statistical analysis showed no significant difference between left and right femoral strain values for the females, but modulus differences were significant different at the p = 0.05 level. There was no significant difference in strain and modulus values for the males, indicating mechanical and geometrical symmetry of their femora.
• Szivek, J. A. (1995). Characterization of three formulations of a synthetic foam as models for a range of human cancellous bone types. Journal of applied biomaterials.
• Szivek, J. A. (1995). Technical note: development of a model for study of in vivo bone strains in normal and microgravity environments. Journal of applied biomaterials.
• Szivek, J. A. (1995). The Changing Face of Surgical Research: From tissue repair to gene replacement. J. of Investigative Surgery, 8(3), 230-233.
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  Guest Editorial on the changes in the approach to treating patients with musculoskeletal injuries or arthritis.
• Szivek, J. A. (1995). The changing face of surgical Research: From tissue repair to gene replacement. Journal of Investigative Surgery.
• Szivek, J. A. (1995). Tibiofemoral contact stress and stress distribution evaluation of total knee arthroplasties. The Journal of Arthroplasty.
• DOHM, M. P., BENJAMIN, J. B., HARRISON, J., & SZIVEK, J. A. (1994). A Biomechanical Evaluation of 3 Forms of Internal-Fixation Used in Ankle Arthrodesis. Foot & Ankle International, 15(6), 297-300.
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  A biomechanical study was undertaken to evaluate the relative stability of three types of internal fixation used for ankle arthrodesis. Crossed screw fixation, RAF fibular strut fixation, and T-plate fixation were tested in 30 cadaver ankles using an MTS machine. T-plate fixation consistently provided the stiffest construct when compared with the other types of fixation. Failure occurred by distraction of bony surfaces, posterior to the plane of fixation, in the crossed screw and RAF groups. In contrast, failure in the T-plate group occurred through compression of bone anterior to the midcoronal plane of the tibia. Although the stability of fixation is only one factor in determining the success or failure of ankle arthrodesis, the results of this study would support T-plate fixation over the other forms tested.
• Szivek, J. A. (1994). A biomechanical evaluation of three forms of internal fixation used in ankle arthrodesis. Foot and Ankle International.
• Szivek, J. A. (1994). Bone remodeling and in vivo strain analysis of intact and implanted greyhound proximal femora. Journal of Investigative Surgery.
• Szivek, J. A. (1994). Load transfer through a hydroxyapatite-coated canine hip implant. Journal of applied biomaterials.
• Szivek, J. A. (1994). Strain redistribution in the canine femur resulting from hip implants of different stiffnesses. Journal of Investigative Surgery.
• Szivek, J. A. (1994). Technical note. Symmetry of biomechanical properties in canine femora. Journal of applied biomaterials.
• Szivek, J. A. (1993). Characterization of a synthetic foam as a model for human cancellous bone.. Journal of applied biomaterials : an official journal of the Society for Biomaterials.
• Szivek, J. A. (1993). Hydroxyapatite-coated strain gauges for long-term in vivo bone strain measurements.. Journal of applied biomaterials : an official journal of the Society for Biomaterials.
• Szivek, J. A. (1992). Bioceramic coatings for artificial joint fixation. Investigative Radiology.
• Szivek, J. A. (1992). In vivo strain analysis of the greyhound femoral diaphysis. Journal of Investigative Surgery.
• Szivek, J. A. (1991). Comparison of the deformation response of synthetic and cadaveric femora during simulated one-legged stance.. Journal of applied biomaterials : an official journal of the Society for Biomaterials.
• SZIVEK, J. A., WENG, M. S., & KARPMAN, R. R. (1990). Variability in the Torsional and Bending Response of a Commercially Available Composite Femur. Journal of Applied Biomaterials, 1(2), 183-186.
• Szivek, J. A. (1990). Preliminary development of a hydroxyapatite-backed strain gauge.. Journal of applied biomaterials : an official journal of the Society for Biomaterials.
• Szivek, J. A., Magee, F. P., Laananen, D. H., & Johnson, E. M. (1990). Bone remodelling in exercised versus cage rested dogs. Journal of Biomechanics, 23(7), 721. doi:10.1016/0021-9290(90)90206-i
• Szivek, J. A. (1989). A comparison of femoral rods in static and locking conditions. Surgical Forum.
• Szivek, J. A. (1989). A long-term in vivo bone strain measurement device. Journal of Investigative Surgery.
• Szivek, J. A. (1989). A testing technique allowing cyclic application of axial, bending, and torque loads to fracture plates to examine screw loosening. Journal of Biomedical Materials Research.
• Szivek, J. A., & Magee, F. P. (1989). A Long Term In Vivo Bone Strain Measurement Device. Journal of Investigative Surgery, 2(2), 195-206.
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  Development of a long term in vivo bone strain measurement device using a porous surfaced metal transducer type system
• Szivek, J. A., & Yapp, R. A. (1989). A Testing Technique Allowing Cyclic Application of Axial, Bending and Torque Loads to Fracture Fixation Plates to Examine Screw Loosening. Journal of Applied Biomaterials, 23(Supplemental), 105-116.
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  Axial, Bending and Torque Loading technique to test Fracture Fixation Plates in order to Examine Screw Loosening
• Szivek, J. A. (1987). The effect of proximally and fully porous‐coated canine hip stem design on bone modeling. Journal of Orthopaedic Research.
• Szivek, J. A. (1981). A study of bone remodeling using metal‐polymer laminates. Journal of Biomedical Materials Research.
• Szivek, J. A. (1979). Bone ingrowth and stress shielding with a porous surface coated fracture fixation plate. Journal of Biomedical Materials Research.

Proceedings Publications

• Figueroa, G., Gonzales, D. A., Viiialobos, E. B., Arciniaga, L. F., Loy, D. A., Muralidharan, K., Potter, B. G., Szivek, J. A., & Margolis, D. S. (2021, April). Resorbable Composite Polymer Ceramic Scaffolds Support Bone Growth and Bonding In Vivo. In Society for Biomaterials, Virtual Meeting.
• Szivek, J. A., Arciniaga, L. F., Rajendran, V., Loy, D. A., Barron Villalobos, E., Gonzales, D. A., & Margolis, D. S. (2020, February). Osteoconductive Biomimetic Polymer Ceramic Bone Scaffolds. In Orthopedic Research Society, Phoenix Arizona February 2020.
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  Osteoconductive Biomimetic Polymer Ceramic Bone Scaffolds
• Szivek, J. A., Margolis, D. S., Gonzales, D. A., Barron Villalobos, E., Gutruf, P., Peralta, R. W., & Cai, L. (2020, August). Direct Measurement of In Vivo Bone Strain with Implantable Wireless Battery Free Devices. In Dept of Defence, Military Health Conf, MHSRS, Kissimmee FL, August 2020.
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  Direct Measurement of In Vivo Bone Strain with Implantable Wireless Battery Free Devices
• Szivek, J. A., Margolis, D. S., Barron Villalobos, E., Arciniaga, L. F., Rajendran, V., Gonzales, D. A., & Loy, D. A. (2020, February). Resorbable Polymer Ceramic Composite Biomimetic Scaffolds Support Osteoblastic Differentiation of Stem Cells. In Orthopedic Research Society, Phoenix Arizona February 2020.
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  Resorbable Polymer Ceramic Composite Biomimetic Scaffolds Support Osteoblastic Differentiation of Stem Cells
• Szivek, J. A., Margolis, D. S., Gonzales, D. A., & Barron Villalobos, E. (2020, August). Can Direct Loading Measurements Define the Extent of Healing in Sensate Long Bone Segment Regeneration Scaffolds. In Dept of Defence, Military Health Conf, MHSRS, Kissimmee FL, August 2020.
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  Can Direct Loading Measurements Define the Extent of Healing in Sensate Long Bone Segment Regeneration Scaffolds
• Szivek, J. A. (2019). Stem cells are necessary to bridge a critical size gap when a biomimetic scaffold is used to regenerate a large segmental femoral defect. In Transactions of the Annual Meeting of the Society for Biomaterials and the Annual International Biomaterials Symposium.
• Szivek, J. A. (2018). Structural and functional assessment of intense therapeutic ultrasound effects on partial Achilles tendon transection. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE.
• Szivek, J. A. (2017). A model for use in the prognosis of tendinopathy. In Simulation Series.
• Szivek, J. A. (2016). Minimizing strain error for in vivo ultra-sound elasticity imaging of human tendon. In IEEE International Ultrasonics Symposium, IUS.
• Szivek, J. A. (2016, December). Environmental Stress Increases Stem Cell Concentration In Extracted Stromal Cell Batches. In Tissue Engineering Part A.
• Szivek, J. A. (2008). In vivo bone strain measurements collected from mouse femora using CPC coated strain Gauges. In 8th World Biomaterials Congress 2008.
• Szivek, J. A. (2008). PBT scaffolds with a biomimetic trabecular porous architecture accelerates bone growth into scaffold pores. In 8th World Biomaterials Congress 2008.
• Szivek, J. A. (2008). Sensate PBT scaffolds measure changes in joint loading and drug efficacy following ACL transection to induce osteoarthrits. In 8th World Biomaterials Congress 2008.
• Szivek, J. A. (2004). Bone remodeling in CAII deficient and calbindin-D28k KO mice. In Transactions - 7th World Biomaterials Congress.
• Szivek, J. A. (2004). Determination of contact pressures in the canine stifle joint. In Transactions - 7th World Biomaterials Congress.
• Szivek, J. A. (2004). Effects of calcium phosphate ceramic surface coatings on cell attachment and spreading. In Transactions - 7th World Biomaterials Congress.
• Szivek, J. A. (2004). Resorbable polymer-ceramic composites for orthopedic scaffold applications. In Ceramic Engineering and Science Proceedings.
• Szivek, J. A. (2004). TGF-ß1 accelerates bone growth into porous TCP-coated PBT scaffolds. In Transactions - 7th World Biomaterials Congress, 359.
• Szivek, J. A. (1996). Characterization of UHMWPE wear debris in synovial fluids of patients with total knee replacements. In Transactions of the Annual Meeting of the Society for Biomaterials in conjunction with the International Biomaterials Symposium.
• Szivek, J. A. (1996). Factors affecting bonding rate of calcium phosphate ceramic coatings for in vivo strain gage attachment. In Transactions of the Annual Meeting of the Society for Biomaterials in conjunction with the International Biomaterials Symposium.
• Szivek, J. A. (1991). Comparison of two hydroxyapatite coating techniques for use as strain gauge bonding systems. In Transactions of the Annual Meeting of the Society for Biomaterials in conjunction with the International Biomaterials Symposium.
• Szivek, J. A. (1991). HA coating enhancement of cancellous screw removal torques. In Transactions of the Annual Meeting of the Society for Biomaterials in conjunction with the International Biomaterials Symposium.
• Johnson, E. M., Szivek, J. A., Magee, F. P., & Laananen, D. H. (1990, Spring). Bone Remodelling in exercised verses cage rested dogs. In Annual meeting of the Society of Biomechanics, 23, 721.
• Szivek, J. A. (1989). Study of activity induced bone remodelling. In American Society of Mechanical Engineers, Applied Mechanics Division, AMD.
• Weng, M. S., Szivek, J. A., & Karpman, R. R. (1989, Spring). Axial Loading of Statically and Dynamically Locked Intramedullary Rods in the Femur. In Orthopaedic Research Society, 1, 13.
• Szivek, J. A. (1988). Novel technique for long term attachment of strain gauges to living bone for in-vivo bone strain measurement. In Instrumentation in the Aerospace Industry, Proceedings of the ISAAerospace Instrumentation Symposium.
• Szivek, J. A., Magee, F. P., & Johnson, E. M. (1987, Spring). A new technique for long term in-vivo bone strain measurement. In Orthopaedic Research Society, 11, 275 - 276.
• Bobyn, J. D., Pilliar, R. M., Binnington, A. G., & Szivek, J. A. (1985, Spring). The effect of partially and fully porous‐coated canine hip stem design on biological fixation and adaptive bone modeling. In Orthopaedic Research Society, 9, 286 - 287.
• Szivek, J. A. (1985, Spring). QUANTITATIVE STUDY OF THE EFFECT OF STRAIN REDISTRIBUTION ON BONE REMODELLING NEAR A POROUS SURFACED IMPLANT.. In Trans of the Ann Mtg of the Soc for Biomaterials in conjunction with the International Biomaterials Society.
• Szivek, J. A., Cameron, H. U., Weatherly, G. C., & Pilliar, R. M. (1985, Spring). A Quantitative Study of the Effect of Strain Redistribution on Bone Remodelling. In Orthopaedic Research Society, 9, 375 - 376.
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  PhD Thesis
• Szivek, J. A., Cameron, H. R., Weatherly, G. C., & Pilliar, R. M. (1981, Spring). A study of bone remodeling using biologically attached composite on-lay plates. In Orthopaedic Research Society, 5, 234 - 235.
• Szivek, J. A., Bobyn, J. D., Pilliar, R. M., Weatherly, G. C., & Cameron, H. U. (1979). A LAMINATED POLYMER-METAL FIXATION PLATE REDUCED STRESS SHIELDING with FRACTURE STABILIZATION. In Society for Biomaterials, 73-76.

Presentations

• Szivek, J. A., Margolis, D. S., & Larson, D. (2019, January). Patient Specific Scaffolds for Treatment of Scaphoid Fractures and Nonunions with Significant Bone Loss. American Association for Hand Surgery Annual Meeting. Palm Desert, CA: American Association for Hand Surgery.
• Szivek, J. A., Margolis, D. S., Gonzales, D. A., Barron, E., & Larson, D. (2019, September). Development of a Porcine Model to Treat Scaphoid Nonunion with 3D Printed Scaffolds. 7th Annual meeting of the ASSH. Las Vegas NV: ASSH.
• Barton, J. K., Rice, P. S., Howard, C., Koevary, J. W., Danforth, F., Gonzales, D. A., Vande Geest, J., Latt, D., Szivek, J. A., Amodei, R., & Slayton, M. (2018, January). Structural and functional assessment of intense therapeutic ultrasound effects on partial Achilles tendon transection. Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XVI, part of SPIE BiOS. San Francisco, CA: SPIE BiOS.
• Szivek, J. A., Buchak, J., & Smith, J. L. (2017, April). A Patient Specific 3D Printed Scaffold for Femoral Long Segment Regeneration. Annual Society for Biomaterials Meeting. Minneapolis, MN: Society for Biomaterials.
• Szivek, J. A., Buchak, J., Wotanowski, A. M., Gonzales, D. A., Barreda, A., Smith, J. L., & Margolis, D. S. (2017, June). Development and Biomechanical Testing of a Human Long Bone Segment Regenerating Scaffold. Summer Biomechancis, Bioengineering and Biotransport Conference (SB3C). Tucson, AZ.
• Latt, D. L., Gao, L., Taljanovic, M., Szivek, J. A., Guerra, J. D., Klewer, J. A., & Witte, R. S. (2016, March). In Vivo Ultrasound Elasticity Imaging Differentiates Healthy From Diseased Tendons. Orthopaedic Research Society 2016 Annual Meeting. Orlando, Florida.
• Szivek, J. A., Okarski, K. M., Curtis, H. J., & Powers, L. S. (2016, December). Environmental Stress Increases Stem Cell Concentration In Extracted Stromal Cell Batches. TERMIS - Published in Tissue Engineering Part A, Vol 22, S8-S8, ISSN 1937-3341, 2016. San Diego, California: TERMIS.
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  Environmental Stress Increases Stem Cell Concentration In Extracted Stromal Cell Batches

Poster Presentations

• Barron, E., Barreda, A., Gonzales, D. A., & Szivek, J. A. (2017, November). Infiltration path evaluation in human sized scaffolds for a segmental defect. Junior Investigator Poster Forum, University of Arizona. Tucson, AZ: University of Arizona.
• Gonzales, D. A., Wojtanowski, A. M., Kay, R. D., Margolis, D. S., Smith, J. L., & Szivek, J. A. (2017, November). Cell Infiltrated Scaffolds Induce Extensive Bone Growth in Critical Sized Defects. Junior Investigator Poster Forum, University of Arizona. Tucson, AZ: University of Arizona.
• Smith, J. L., Barreda, A., Gonzales, D. A., Wojtanowski, A. M., Buchak, J., Szivek, J. A., & Margolis, D. S. (2017, June). Development and Testing of a Long Bone Segment Regenerating Scaffold for Patients.. Summer Biomechanics, Bioengineering and Biotransport Conference. Tucson, Arizona: SB3C.
• Szivek, J. A., Gonzales, D. A., Kay, R. D., Margolis, D. S., & Smith, J. L. (2017, Summer). Cell-Free Biomimetic Scaffolds Lead to Non-Unions in Critical Sized Defect Repair as Compared to Identically Structured Stem Cell Infiltrated Scaffolds that Induce Rapid Bone Growth. Orthopaedic Research Society - Sun Valley Workshop. Sun Valley: Orthopaedic Research Society.
• Szivek, J. A., Walker, K., & Gonzales, D. A. (2017, November). Evaluation of a Cavitation-Based Extraction of Adipose Derived Stromal Cells for Clinical Testing. Junior Investigator Poster Forum, University of Arizona. Tucson, AZ: University of Arizona.
• Schmitz, H., Gao, L., Ingram, C. P., Klewer, J., Szivek, J. A., Taljanovic, M., Latt, D. L., & Witte, R. S. (2016, January). Ultrasound Elasticity Imaging of the Posterior Tibial Tendon using FOCUS Simulation Software. 27th Annual Undergraduate Biology Research Program Conference. Tucson, AZ.

Others

• Szivek, J. A. (1984, September). A Quantitative Study of the Effect of Strain Redistribution on Bone Remodelling. Thesis.
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  PhD Thesis