Journal of bone biology and osteoporosis, Oct 26, 2015
Increased cost and complexity associated with orthopaedic surgeries has led to advancements in de... more Increased cost and complexity associated with orthopaedic surgeries has led to advancements in degradable materials. Degradable metals like magnesium have shown great promise as magnesium based alloys provide the strength of metals but the degradability of polymers. As the development of degradable magnesium alloys expands there is a significant need for simplified computational models that can account for the numerous mechanical changes associated with degradation. The current study examined initial in silico models of Magnesium samples to gain insight on how degradation impacts mechanical performance over time. Models of magnesium rods were created and analyzed using the finite element analysis functionality in a commercially available software package. SolidWorks is widely known for its design capabilities and generation of 3D solid models; however its analyses capabilities would be useful for such a smart material, like magnesium. Therefore, this work explores the analysis capabilities of SolidWorks, for degradable magnesium in a skeletal environment.
Black individuals are underrepresented in science, technology, engineering, and mathematics (STEM... more Black individuals are underrepresented in science, technology, engineering, and mathematics (STEM) fields. In 2016, Black students earned 9% of science and 4% of engineering bachelor's degrees compared to a total of 56% of science and engineering bachelor's degrees earned by White students. Even with similar entering rates, Black students leave STEM majors at 1.4 times the rate of White students. These data reflect the manifestation of diversity, equity, and inclusion (DEI) barriers faced by Black students and scientists to successfully navigate higher education and pursue careers in STEM fields. There remains a critical need to develop better ways to recruit, retain, train, and graduate Black students in STEM, especially within predominantly White institutions. Biomechanics is a growing interdisciplinary and translational STEM field where DEI barriers persist. Thus, the Black Biomechanists Association (BBA) was founded in 2020 with intentions to reduce these barriers and give much needed support to Black students and biomechanists in STEM spaces. The organization's mission is to uplift and enrich Black biomechanists in their academic and professional careers. Our objectives to achieve this mission provide a supportive environment and resources to address the challenges, needs, and interests of Black biomechanists, as well as aid in the biomechanics community's efforts to achieve DEI. In two short years, BBA has developed a needs-based mentoring program, hosted professional development and culturally-competent mentoring workshops, and produced communications to educate the biomechanics community and broader audience on culturally-relevant topics that impact Black biomechanists. The purpose of this article is to share the work and impact of BBA to date.
The anterior cruciate ligament (ACL) is the most often injured knee ligament with well over 100,0... more The anterior cruciate ligament (ACL) is the most often injured knee ligament with well over 100,000 injuries in the United States, annually. ACL reconstruction is the most common surgical treatment and involves replacing the damaged ACL with a soft tissue graft. ACL interference screws are often used to fix the graft into place. The early success of the reconstruction surgery depends on the graft fixation method. Several investigators have studied the effect of the properties of interference screws (i.e. screw design parameters) on their performance. Some have employed the use of finite element analysis (FEA), a computational method that can simulate loading conditions on differing screw designs. This review gives an overview of ACL interference screw usage and design as well as an in depth review of studies that have used FEA to assess ACL interference screw performance. Finally, future directions of how FEA can be used to optimize interference screw design and implementation are discussed.
Healthcare in the United States and across the world continues to face unique challenges. While t... more Healthcare in the United States and across the world continues to face unique challenges. While these challenges and even methods/technology for meeting these challenges change, the central goal remains the same, to improve the health and wellbeing of people, all people. One unique aspect of health care delivery is the prevalence of health disparities. Multiple definitions exist for a health disparity, a working description was stated by Warnecke et al. [1], “A difference may become a disparity when some subgroups and not others are given access to resources to manage their differential risk from biological or other factors and the groups without access have poorer outcomes.” As efforts continue to address the complex issues associated with health disparities, several notable conferences are dedicated to discussing problems and potential solutions. The corresponding author enjoys these conferences and learning about the tremendous work being done in the field. His attendance also ra...
Third-generation total wrist arthroplasty devices have provided joint stability, relief from pain... more Third-generation total wrist arthroplasty devices have provided joint stability, relief from pain and increased wrist motion for patients suffering from severe arthritis. While reports of clinical follow-up appointments describe improved wrist function, the improvement in overall upper extremity function and patient perception remains a question. Therefore, the purpose of this study was to assess the upper extremity function in patients that received the Universal 2 total implant system. Eight patients participated in the complete protocol, which included testing activities of daily living as well as surveys to assess patient perception. The findings of the current study suggest that although patients exhibit motion that exceeds the needed amount, many still have a perceived disability.
2015 ASEE Annual Conference and Exposition Proceedings
Bioengineering, he has his B.S. in Industrial Engineering from North Carolina A&T and his Ph.D. i... more Bioengineering, he has his B.S. in Industrial Engineering from North Carolina A&T and his Ph.D. in Biomedical Engineering from the University of Iowa. His research involves musculoskeletal biomechanics with a focus on computational methods. He is also deeply interested in engineering education and especially creating opportunities for underrepresented minorities and women in the field.
2015 ASEE Annual Conference and Exposition Proceedings
(NCAT). Dr. Bhattarai teaches biomaterials and nanotechnology to undergraduate and graduate stude... more (NCAT). Dr. Bhattarai teaches biomaterials and nanotechnology to undergraduate and graduate students. He is principal investigator of NUE Enhancing Undergraduate Students' Learning Experiences on Bio-Nanoengineering project at NCAT.
Introduction-Idiopathic inflammatory myopathies (IIM or myositis), is a group of autoimmune disea... more Introduction-Idiopathic inflammatory myopathies (IIM or myositis), is a group of autoimmune diseases that result in decreased muscle strength and/or endurance. Non-invasive tools to assess muscle may improve our understanding of the clinical and functional consequences of myopathies and their response to treatment. This study examined Magnetic Resonance Elastography (MRE), a non-invasive technique that assesses the shear modulus (stiffness) of muscle, in IIM subjects. Methods-Nine subjects with active myositis completed the MRE protocol. Participants lay in a positioning device, and scans of the vastus medialis (VM) were taken in the relaxed state and at two contraction levels. Manual inversion was used to estimate the stiffness. Results-A significant reduction in muscle stiffness was seen in myositis subjects compared with healthy controls during the 'relaxed' condition. Discussion-The use of non-invasive technologies such as MRE may provide greater understanding of the pathophysiology of IIM and improve assessment of treatment efficacy.
INTRODUCTION-In the treatment of wrist arthritis, motion-preserving procedures are commonly prefe... more INTRODUCTION-In the treatment of wrist arthritis, motion-preserving procedures are commonly preferred over complete arthrodesis because it is perceived these procedures provide higher patient satisfaction. Potential reasons for higher satisfaction include better function and reduced impact on other joints. However, reported risks with these procedures include further arthritic changes, failure of fusion, and implant loosening. To justify the risks and added technical challenges associated with these procedures, the benefits should be objectively measurable. Our goals were to quantify and compare the impairments caused by reduced and absent wrist motion using objective measurements of task performance and perceived impairment, and to assess the compensatory motions of the shoulder, elbow, forearm and trunk imposed by impaired wrist motion.
Advances in imaging technologies such as magnetic resonance elastography (MRE) have allowed resea... more Advances in imaging technologies such as magnetic resonance elastography (MRE) have allowed researchers to gain insights into muscle function in vivo. MRE has been used to examine healthy and diseased muscle by calculating shear modulus. However, additional information can be measured from visualizing a mechanical wave as it passes through a tissue. One such measurable quantity is wave attenuation. The purpose of this study was to determine if a simple measure of wave attenuation could be used to distinguish between healthy and diseased muscle. Twenty seven subjects (14 healthy controls, 7 hyperthyroid myopathy patients, 6 myositis patients) participated in this study. Wave amplitude was determined along a linear profile through the center of the muscle, and an exponential decay curve was fit to the data. This measure was able to find significant differences in attenuation between healthy and diseased muscle. Furthermore, four hyperthyroid myopathy subjects who were tested following treatment all showed improvement by this measure. A likely reason for patients with hyperthyroid myopathy and myositis behaving similarly is that this measurement may reflect similar changes in the muscle extracellular matrix. In addition to modulus, attenuation seems to be an important parameter to measure in skeletal muscle. Further research is needed to investigate other potential measures of attenuation as well as examining other potential measures that can be found from visualizing wave propagation. Future studies should also include muscle biopsies to confirm that the changes seen are as a result of changes in extracellular matrix structure.
Background: The moment, a force applied at a distance, is responsible for movement and balance. A... more Background: The moment, a force applied at a distance, is responsible for movement and balance. A key component of the moment is the moment arm. The moment arms of nine muscles surrounding the ankle complex during motion in three planes, were studied. Materials and Methods: Five cadaveric feet were mounted in a testing device that created moments in the sagittal, coronal and transverse planes. Axial and tendon loads were applied as the foot was passively moved in these planes. Tendon excursions and bone kinematics were monitored. The moment arm was calculated using the tendon excursion method and averaged across all specimens. Results: The largest average moment arm during plantarflexion/dorsiflexion, was the Achilles (mean, 53.1; SD, 5.1 mm). During internal/external rotation the largest moment arm was the peroneus brevis (mean, 20.5; SD, 6.4 mm). During inversion/eversion, the largest moment arm was the peroneus longus (31 mm; SD, 2.3 mm). Conclusion: This study quantified the fun...
Posterior tibial tendon dysfunction is a significant contributor to flatfeet. Non-operative treat... more Posterior tibial tendon dysfunction is a significant contributor to flatfeet. Non-operative treatments, like in-shoe orthoses, have varying degrees of success. This study examined changes to the work of friction of the posterior tibial tendon under three conditions: intact, simulated flatfoot, and flatfoot with an orthosis. It was hypothesized that work of friction of the posterior tibial tendon would significantly increase in the flatfoot, yet return to normal with an orthosis. Changes to bone orientation were also expected. Six lower limb cadavers were mounted in a foot simulator, that applied axial and a posterior tibial tendon load. Posterior tibial tendon excursion, gliding resistance, and foot kinematics were monitored, and work of friction calculated. Each specimen moved through a range of motion in the coronal, transverse, and sagittal planes. Mean work of friction during motion in the coronal plane were 0.17 N cm (SD 0.07 N cm), 0.25 N cm (SD 0.09 N cm), and 0.23 N cm (SD 0.09 N cm) for the intact, flatfoot, and orthosis conditions, respectively. Motion in the transverse plane yielded average WoF of 0.36 N cm (SD 0.28 N cm), 0.64 N cm (SD 0.25 N cm), and 0.57 N cm (SD 0.38 N cm) in the same three conditions, respectively. The average tibio-calcaneal and tibio-metatarsal valgus angles significantly increased in the flatfoot condition (5.8 degrees and 9 degrees , respectively). However, the orthosis did slightly correct this angle. The prefabricated orthosis did not consistently restore normal work of friction, though it did correct the flatfoot visually. This implies that patients with flatfeet may be predisposed to developing posterior tibial tendon dysfunction due to abnormal gliding resistance, though bone orientations are restored.
An examination possible quadriceps force at the time of anterior cruciate ligament injury during ... more An examination possible quadriceps force at the time of anterior cruciate ligament injury during landing: A simulation study.
Journal of bone biology and osteoporosis, Oct 26, 2015
Increased cost and complexity associated with orthopaedic surgeries has led to advancements in de... more Increased cost and complexity associated with orthopaedic surgeries has led to advancements in degradable materials. Degradable metals like magnesium have shown great promise as magnesium based alloys provide the strength of metals but the degradability of polymers. As the development of degradable magnesium alloys expands there is a significant need for simplified computational models that can account for the numerous mechanical changes associated with degradation. The current study examined initial in silico models of Magnesium samples to gain insight on how degradation impacts mechanical performance over time. Models of magnesium rods were created and analyzed using the finite element analysis functionality in a commercially available software package. SolidWorks is widely known for its design capabilities and generation of 3D solid models; however its analyses capabilities would be useful for such a smart material, like magnesium. Therefore, this work explores the analysis capabilities of SolidWorks, for degradable magnesium in a skeletal environment.
Black individuals are underrepresented in science, technology, engineering, and mathematics (STEM... more Black individuals are underrepresented in science, technology, engineering, and mathematics (STEM) fields. In 2016, Black students earned 9% of science and 4% of engineering bachelor's degrees compared to a total of 56% of science and engineering bachelor's degrees earned by White students. Even with similar entering rates, Black students leave STEM majors at 1.4 times the rate of White students. These data reflect the manifestation of diversity, equity, and inclusion (DEI) barriers faced by Black students and scientists to successfully navigate higher education and pursue careers in STEM fields. There remains a critical need to develop better ways to recruit, retain, train, and graduate Black students in STEM, especially within predominantly White institutions. Biomechanics is a growing interdisciplinary and translational STEM field where DEI barriers persist. Thus, the Black Biomechanists Association (BBA) was founded in 2020 with intentions to reduce these barriers and give much needed support to Black students and biomechanists in STEM spaces. The organization's mission is to uplift and enrich Black biomechanists in their academic and professional careers. Our objectives to achieve this mission provide a supportive environment and resources to address the challenges, needs, and interests of Black biomechanists, as well as aid in the biomechanics community's efforts to achieve DEI. In two short years, BBA has developed a needs-based mentoring program, hosted professional development and culturally-competent mentoring workshops, and produced communications to educate the biomechanics community and broader audience on culturally-relevant topics that impact Black biomechanists. The purpose of this article is to share the work and impact of BBA to date.
The anterior cruciate ligament (ACL) is the most often injured knee ligament with well over 100,0... more The anterior cruciate ligament (ACL) is the most often injured knee ligament with well over 100,000 injuries in the United States, annually. ACL reconstruction is the most common surgical treatment and involves replacing the damaged ACL with a soft tissue graft. ACL interference screws are often used to fix the graft into place. The early success of the reconstruction surgery depends on the graft fixation method. Several investigators have studied the effect of the properties of interference screws (i.e. screw design parameters) on their performance. Some have employed the use of finite element analysis (FEA), a computational method that can simulate loading conditions on differing screw designs. This review gives an overview of ACL interference screw usage and design as well as an in depth review of studies that have used FEA to assess ACL interference screw performance. Finally, future directions of how FEA can be used to optimize interference screw design and implementation are discussed.
Healthcare in the United States and across the world continues to face unique challenges. While t... more Healthcare in the United States and across the world continues to face unique challenges. While these challenges and even methods/technology for meeting these challenges change, the central goal remains the same, to improve the health and wellbeing of people, all people. One unique aspect of health care delivery is the prevalence of health disparities. Multiple definitions exist for a health disparity, a working description was stated by Warnecke et al. [1], “A difference may become a disparity when some subgroups and not others are given access to resources to manage their differential risk from biological or other factors and the groups without access have poorer outcomes.” As efforts continue to address the complex issues associated with health disparities, several notable conferences are dedicated to discussing problems and potential solutions. The corresponding author enjoys these conferences and learning about the tremendous work being done in the field. His attendance also ra...
Third-generation total wrist arthroplasty devices have provided joint stability, relief from pain... more Third-generation total wrist arthroplasty devices have provided joint stability, relief from pain and increased wrist motion for patients suffering from severe arthritis. While reports of clinical follow-up appointments describe improved wrist function, the improvement in overall upper extremity function and patient perception remains a question. Therefore, the purpose of this study was to assess the upper extremity function in patients that received the Universal 2 total implant system. Eight patients participated in the complete protocol, which included testing activities of daily living as well as surveys to assess patient perception. The findings of the current study suggest that although patients exhibit motion that exceeds the needed amount, many still have a perceived disability.
2015 ASEE Annual Conference and Exposition Proceedings
Bioengineering, he has his B.S. in Industrial Engineering from North Carolina A&T and his Ph.D. i... more Bioengineering, he has his B.S. in Industrial Engineering from North Carolina A&T and his Ph.D. in Biomedical Engineering from the University of Iowa. His research involves musculoskeletal biomechanics with a focus on computational methods. He is also deeply interested in engineering education and especially creating opportunities for underrepresented minorities and women in the field.
2015 ASEE Annual Conference and Exposition Proceedings
(NCAT). Dr. Bhattarai teaches biomaterials and nanotechnology to undergraduate and graduate stude... more (NCAT). Dr. Bhattarai teaches biomaterials and nanotechnology to undergraduate and graduate students. He is principal investigator of NUE Enhancing Undergraduate Students' Learning Experiences on Bio-Nanoengineering project at NCAT.
Introduction-Idiopathic inflammatory myopathies (IIM or myositis), is a group of autoimmune disea... more Introduction-Idiopathic inflammatory myopathies (IIM or myositis), is a group of autoimmune diseases that result in decreased muscle strength and/or endurance. Non-invasive tools to assess muscle may improve our understanding of the clinical and functional consequences of myopathies and their response to treatment. This study examined Magnetic Resonance Elastography (MRE), a non-invasive technique that assesses the shear modulus (stiffness) of muscle, in IIM subjects. Methods-Nine subjects with active myositis completed the MRE protocol. Participants lay in a positioning device, and scans of the vastus medialis (VM) were taken in the relaxed state and at two contraction levels. Manual inversion was used to estimate the stiffness. Results-A significant reduction in muscle stiffness was seen in myositis subjects compared with healthy controls during the 'relaxed' condition. Discussion-The use of non-invasive technologies such as MRE may provide greater understanding of the pathophysiology of IIM and improve assessment of treatment efficacy.
INTRODUCTION-In the treatment of wrist arthritis, motion-preserving procedures are commonly prefe... more INTRODUCTION-In the treatment of wrist arthritis, motion-preserving procedures are commonly preferred over complete arthrodesis because it is perceived these procedures provide higher patient satisfaction. Potential reasons for higher satisfaction include better function and reduced impact on other joints. However, reported risks with these procedures include further arthritic changes, failure of fusion, and implant loosening. To justify the risks and added technical challenges associated with these procedures, the benefits should be objectively measurable. Our goals were to quantify and compare the impairments caused by reduced and absent wrist motion using objective measurements of task performance and perceived impairment, and to assess the compensatory motions of the shoulder, elbow, forearm and trunk imposed by impaired wrist motion.
Advances in imaging technologies such as magnetic resonance elastography (MRE) have allowed resea... more Advances in imaging technologies such as magnetic resonance elastography (MRE) have allowed researchers to gain insights into muscle function in vivo. MRE has been used to examine healthy and diseased muscle by calculating shear modulus. However, additional information can be measured from visualizing a mechanical wave as it passes through a tissue. One such measurable quantity is wave attenuation. The purpose of this study was to determine if a simple measure of wave attenuation could be used to distinguish between healthy and diseased muscle. Twenty seven subjects (14 healthy controls, 7 hyperthyroid myopathy patients, 6 myositis patients) participated in this study. Wave amplitude was determined along a linear profile through the center of the muscle, and an exponential decay curve was fit to the data. This measure was able to find significant differences in attenuation between healthy and diseased muscle. Furthermore, four hyperthyroid myopathy subjects who were tested following treatment all showed improvement by this measure. A likely reason for patients with hyperthyroid myopathy and myositis behaving similarly is that this measurement may reflect similar changes in the muscle extracellular matrix. In addition to modulus, attenuation seems to be an important parameter to measure in skeletal muscle. Further research is needed to investigate other potential measures of attenuation as well as examining other potential measures that can be found from visualizing wave propagation. Future studies should also include muscle biopsies to confirm that the changes seen are as a result of changes in extracellular matrix structure.
Background: The moment, a force applied at a distance, is responsible for movement and balance. A... more Background: The moment, a force applied at a distance, is responsible for movement and balance. A key component of the moment is the moment arm. The moment arms of nine muscles surrounding the ankle complex during motion in three planes, were studied. Materials and Methods: Five cadaveric feet were mounted in a testing device that created moments in the sagittal, coronal and transverse planes. Axial and tendon loads were applied as the foot was passively moved in these planes. Tendon excursions and bone kinematics were monitored. The moment arm was calculated using the tendon excursion method and averaged across all specimens. Results: The largest average moment arm during plantarflexion/dorsiflexion, was the Achilles (mean, 53.1; SD, 5.1 mm). During internal/external rotation the largest moment arm was the peroneus brevis (mean, 20.5; SD, 6.4 mm). During inversion/eversion, the largest moment arm was the peroneus longus (31 mm; SD, 2.3 mm). Conclusion: This study quantified the fun...
Posterior tibial tendon dysfunction is a significant contributor to flatfeet. Non-operative treat... more Posterior tibial tendon dysfunction is a significant contributor to flatfeet. Non-operative treatments, like in-shoe orthoses, have varying degrees of success. This study examined changes to the work of friction of the posterior tibial tendon under three conditions: intact, simulated flatfoot, and flatfoot with an orthosis. It was hypothesized that work of friction of the posterior tibial tendon would significantly increase in the flatfoot, yet return to normal with an orthosis. Changes to bone orientation were also expected. Six lower limb cadavers were mounted in a foot simulator, that applied axial and a posterior tibial tendon load. Posterior tibial tendon excursion, gliding resistance, and foot kinematics were monitored, and work of friction calculated. Each specimen moved through a range of motion in the coronal, transverse, and sagittal planes. Mean work of friction during motion in the coronal plane were 0.17 N cm (SD 0.07 N cm), 0.25 N cm (SD 0.09 N cm), and 0.23 N cm (SD 0.09 N cm) for the intact, flatfoot, and orthosis conditions, respectively. Motion in the transverse plane yielded average WoF of 0.36 N cm (SD 0.28 N cm), 0.64 N cm (SD 0.25 N cm), and 0.57 N cm (SD 0.38 N cm) in the same three conditions, respectively. The average tibio-calcaneal and tibio-metatarsal valgus angles significantly increased in the flatfoot condition (5.8 degrees and 9 degrees , respectively). However, the orthosis did slightly correct this angle. The prefabricated orthosis did not consistently restore normal work of friction, though it did correct the flatfoot visually. This implies that patients with flatfeet may be predisposed to developing posterior tibial tendon dysfunction due to abnormal gliding resistance, though bone orientations are restored.
An examination possible quadriceps force at the time of anterior cruciate ligament injury during ... more An examination possible quadriceps force at the time of anterior cruciate ligament injury during landing: A simulation study.
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Papers by Matthew McCullough