Biomechanics Research Staff

Department of Biomechanics
AMT Center
510 East 73rd Street, Room 202
New York, NY 10021

Tel: 646.797.8532
Email: GlendayJ@hss.edu

About Jonathan Glenday

Jonathan Glenday joined Hospital for Special Surgery in March 2020 as a Postdoctoral Fellow to work in collaboration with the Adult Reconstruction and Joint Replacement Service. His research aims to improve implant longevity by understanding how total knee arthroplasty (TKA) surgical choices effect bone-implant interaction. Alongside his team members in the Department of Biomechanics, he has developed a computational workflow that connects musculoskeletal models with finite element models to quantify the effect of component alignment and design on the stability and fixation of TKA. 

Jonathan obtained both his undergraduate degree in Electromechanical Engineering and his doctoral degree in Biomedical Engineering from the University of Cape Town in South Africa. His doctoral research, which was conducted in collaboration with the Motion Analysis Laboratory at Hospital for Special Surgery, utilized computational modelling to optimize prosthesis alignment for reverse total shoulder arthroplasty. Jonathan completed his doctoral degree in 2018 and, in 2019, he worked as a Postdoctoral Researcher at the University of Tübingen in Germany. During his time there, he developed a musculoskeletal model of the wrist to assess the risk factors associated with carpal tunnel syndrome.

Education

2014 – 2018: PhD in Biomedical Engineering – University of Cape Town, South Africa. 
2010 – 2013: BSc(Eng) in Electromechanical Engineering - University of Cape Town, South Africa.
Awards
2020:  Best presentation in computational modeling for arthroplasty – 1st ISTA New Early-career Webinar Series.
2018: Best shoulder presentation – 64th South African Orthopaedic Congress.

Selected Publications

Dey, R., Glenday, J., du Plessis, J., Sivarasu, S., and Roche, S. (2023). Characterising moment arms of the coracobrachialis and short head of biceps for healthy and reverse total shoulder arthroplasty during elevation and rotation: a modelling study. Journal of Shoulder and Elbow Surgery. DOI: https://doi.org/10.1016/j.jse.2023.01.015.

Glenday, J., Kontaxis, A., Roche, S., and Sivarasu, S. (2021). Development of a framework to assess the biomechanical impact of reverse shoulder arthroplasty placement modifications. Journal of Orthopaedic Research. DOI: https://doi.org/10.1002/jor.25238.

Glenday, J., Wright, T., Lipman, J., Sculco, P., Mayman, D., Vigdorchik, J., and Quevedo-Gonzalez, F. (2021). Effect of varus alignment on the bone-implant interaction of a cementless tibial baseplate during gait. Journal of Orthopaedic Research. DOI: https://doi.org/10.1002/jor.25129.

Glenday, J., Steinhilber B., Jung F., and Haeufle, D.F.B. (2020). Development of a musculoskeletal model of the wrist to predict frictional work dissipated due to tendon gliding resistance in the carpal tunnel. Computer Methods in Biomechanics and Biomedical Engineering. DOI: https://doi.org/10.1080/10255842.2020.1862094.

Glenday, J., Kontaxis, A., Roche, S., and Sivarasu, S. (2019). Effect of humeral tray placement on impingement-free range of motion and muscle moment arms in reverse shoulder arthroplasty. Clinical Biomechanics. 62, 136-143. DOI: https://doi.org/10.1016/j.clinbiomech.2019.02.002.

For more publications, please see the PubMed listing.

Selected Presentations

Glenday, J., Sculco, P., Vigdorchik, J., Lipman, J., Kahlenberg, C., Mayman, D., Wright, T., and Quevedo-Gonzalez, F. Tibial baseplate motion relates to tibiofemoral kinematics during gait: a holistic evaluation of TKA biomechanics using a patient-specific computational workflow. 33rd International Society for Technology in Arthroplasty Congress. (09/2022). 

Glenday, J., Sculco, P., Vigdorchik, J., Lipman, J., Wright, T., and Quevedo-Gonzalez, F. The initial fixation of cementless total knee arthroplasty is associated with the anterior-posterior translation during gait: a computational study. 2022 Annual Meeting of the American Academy of Orthopaedic Surgeons. (03/2022).​​​​

Glenday, J., Wright, T., Lipman, J. Sculco, P., Mayman, D., Vigdorchik, J., and Quevedo-Gonzalez, F. Effect of varus alignment on the bone-implant interaction of cementless tibial baseplates. 1st New Early-career Webinar Series – International Society for Technology in Arthroplasty. (11/2020).

Glenday, J., Kontaxis, A., Roche, S., and Sivarasu, S. Optimisation of reverse shoulder arthroplasty through the combination of prosthesis placement modifications. XXVII Congress of the International Society of Biomechanics. (08/2019).

Department of Biomechanics
AMT Center
510 East 73rd Street, Room 202
New York, NY 10021

Tel: 646.797.8532
Email: winterr@hss.edu

About Remy Winter

Remy Winter joined Hospital for Special Surgery in October 2024 as a Postdoctoral Fellow. His research focuses on understanding how surgical choices in total knee arthroplasty (TKA) impact function and fixation. Using a computational workflow developed at HSS, he integrates musculoskeletal models with finite element models to assess the effects of component alignment and design on TKA stability and fixation. 

Remy earned his mechanical engineering degree and a Master of Science in biomechanics from the École Nationale d’Ingénieurs de Metz (Metz, France) in 2021. He then completed his doctoral studies in clinical research at the University Côte d’Azur (Nice, France) in collaboration with the company Newclip Technics (Haute-Goulaine, France) in 2024. His doctoral research was focused on the development of a 3D wrist model for preoperative planning.

Education

2021– 2024: Ph.D. in Clinical Research, University Côte d’Azur, Nice, France
2020– 2021: M.Sc. in Biomedical Engineering, University of Lorraine, Metz, France
2016 – 2021: Eng. Deg. in Mechanical Engineering, École Nationale d’Ingénieurs de Metz, Metz, France

Selected Publication

Winter R, Citarel A, Chabrand P, Chenel A, Bronsard N, Poujade T, Gauci MO (2024). An evaluation of the reliability of manual landmark identification on 3D segmented wrists. The Journal of Bone and Joint Surgery. doi: 10.2106/JBJS.23.00173.

Winter R, Chabrand P, Viriciel C, Bronsard N, Monin B, Poujade T, Gauci MO (under review). Validation of an automatic three-dimensional method for distal radius measurements and malunion quantification.

Selected Presentations

Winter R, Poujade T, Chabrand P, Gauci MO. Proposal of a new wrist model for surgical planning: the added benefits of 3D analysis. 28th Congress of the European Society of Biomechanics, July 9-12, 2023, Maastricht, the Netherlands.

Winter R, Chabrand P, Viriciel C, Bronsard N, Monin B, Poujade T, Gauci MO. Mesure automatique tridimensionnelle de l’inclinaison et de la pente radiale : validation sur cas sain et séquelles de fractures. French Society of Hand Surgery & SFRM-GEMMSOR Congress December 2024, Paris, France.

Department of Biomechanics
AMT Center
510 East 73rd Street, Room 202-A
New York, NY 10021

Tel: 212.774.7275
Email: pourmodhejir@hss.edu

About Reza Pourmodheji

Reza joined the Biomechanics Department at HSS in February 2022. The focus of his research is knee biomechanics where he integrates robotic experimental tools and physics-based computational approaches from cadaveric and patient-specific measurements to answer the research questions for orthopedic care improvement. He works closely with Adult Reconstruction and Joint Replacement, Sport Medicine and Radiology and Imaging Services at HSS.

Reza obtained his PhD in Mechanical Engineering from the City University of New York where he currently serves as Adjunct Assistant Professor lecturing mechanical engineering courses. Prior to HSS, he was research associate at Michigan State University working on mathematical modeling and mechanobiology in progression of cardiovascular diseases.

Appointments

Postdoctoral Fellow, Department of Biomechanics, Hospital for Special Surgery
Adjunct Assistant Professor, The City University of New York

Education

Ph.D. – Mechanical Engineering, The City University of New York, New York, NY – 2018
M.Sc. – Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran – 2012
B.Sc. – Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran – 2008

Awards

NIH Travel Award, IMAG-MSM 2020, Bethesda, MD
Arthur Goldstein Award for outstanding teach in Mechanical Engineering, The City University of New York, 2019

Department of Biomechanics
Hospital for Special Surgery (HSS)
AMT Center
510 East 73rd Street Room 202
New York NY 10021
Email: kimsun@hss.edu

About Sunjung Kim

Sunjung Kim joined the Hospital for Special Surgery in March 2024 as a Postdoctoral Fellow in the Department of Biomechanics. His work focuses on improving implant fixation and reducing failure rates in total ankle replacement. By integrating cadaveric testing with computational modeling, he aims to minimize micromotion at the bone–implant interface, a key contributor to aseptic loosening and long-term implant failure.

Sunjung earned his PhD in Mechanical Engineering from the University of Wisconsin–Madison. His doctoral research focused on prosthetic joint infection in antibiotic-loaded bone cement, combining mechanical testing with computational modeling to evaluate the impact of antibiotic additives on cement integrity. In 2020, he joined Rosalind Franklin University as a Postdoctoral Researcher to study 3D-printed transtibial prosthetic socket design. In 2023, he continued his postdoctoral training at the University of Illinois at Chicago, where he conducted experimental and computational studies of the knee, wrist, and shoulder to evaluate surgical interventions and musculoskeletal mechanics.

Education

Postdoc, Hospital for Special Surgery, 2024

Postdoc, University of Illinois Chicago, 2023

Postdoc, Rosalind Franklin University, 2022
Ph.D. in Mechanical Engineering, University of Wisconsin - Madison, 2020
M.S. in Mechanical Engineering, University of Wisconsin – Madison, 2017

B.S. in Mechanical Engineering, University of Minnesota, 2014

Award

AOFAS Research Scholarship Award, American Orthopaedic Foot & Ankle Society, 2025

Selected Publication

Kim, S., Nyaaba, W., Mzeihe, M., Mejia, A., Gonzalez, M., and Amirouche, F. (2024). Wrist kinetics post-scapholunate dissociation: Experimental and computational analysis of scapholunate interosseous ligament injury. Journal of Hand Surgery Global Online. https://doi.org/10.1016/j.jhsg.2024.11.011

Kim, S., Mungalpara, N., Wangikar, R., Tarabichi, M., Karam, J., Bedi, A., Koh, J., and Farid, A. (2024). Comparative study of locking neutralization plate construct versus tension band wiring with a cannulated screw for patella fractures: Experimental and finite element analysis. Journal of Orthopaedic Surgery and Research, 19, 77. https://doi.org/10.1186/s13018-024-04538-w

Kim, S., Koh, J., Bedi, A., and Amirouche, F. (2024). Lesion size location dependency on maximum pressure in osteochondral defects: Experiments and finite-element analysis. Orthopaedic Journal of Sports Medicine, 12(10). https://doi.org/10.1177/23259671241281735

Kim, S., Yalla, S.V., Shetty, S., and Rosenblatt, N.J. (2024). Structural integrity of custom-designed additive manufactured prosthetic sockets compared to traditional sockets. Results in Materials, 21, 100549.

https://doi.org/10.1016/j.rinma.2023.100549

Kim, S., Bishop, A.R., Squire, M.W., Rose, W.E., and Ploeg, H.-L. (2020). Mechanical, elution, and antibacterial properties of Simplex bone cement loaded with vancomycin. Journal of the Mechanical Behavior of Biomedical Materials, 103, 103588. https://doi.org/10.1016/j.jmbbm.2019.103588

For more publication, please see the Google scholar listing.

Selected Presentations

Kim, S., Nyaaba, W., Mzeihe, M., Mejia, A., Gonzalez, M., and Amirouche, F. Wrist kinetics post-scapholunate dissociation: Experimental and computational analysis of scapholunate interosseous ligament injury. International Society for Technology in Arthroplasty Annual Congress, Tennessee, USA. (2024)

Kim, S., Wangikar, R., Lichtg, A., Karam, J., Tarabichi, M., Koh, J., and Amirouche, F. Comparative study of a novel cannulated screw and locking neutralization plate construct versus tension band wiring for patella fractures: Experimental and finite element analysis. International Society for Technology in Arthroplasty Annual Congress, New York, USA. (2023)

About Amir Jahandar

Amir Jahandar joined the HSS biomechanics department in 2018 as a research engineer. Throughout his time at HSS, he has focused on experimental and computational orthopaedic research. Amir works in tandem with fellow and resident surgeons on studies aimed at improving surgical complications. This has resulted in extensive experience working on shoulder joint projects using a custom testing device. Shoulder instability is a recurring issue for young patients and athletes. Using the custom shoulder testing device, he has investigated the effect of different surgical treatment methods on patients with rotator cuff and joint capsule injuries.

Additionally, Amir has also investigated surgical interventions for trochlear dysplasia patients using a 3D printed cadaveric knee model to improve understanding of the patellofemoral joint.

Prior to joining HSS Amirhossein received his master’s degree in bioengineering at University of Missouri and enhanced his practical experience working as a research assistant. This research involved using computational multibody dynamics modeling to predict knee contact mechanics during activities of daily living.

Selected Publications

• Nicholson AD, Carey EG, Mathew JI, Pinnamaneni S, Jahandar A, Kontaxis A, Dines DM, Dines JS, Blaine TA, Fu MC, Rodeo SA, Warren RF, Gulotta LV, Taylor SA. Biomechanical analysis of anterior stability after 15% glenoid bone loss: comparison of Bankart repair, dynamic anterior stabilization, dynamic anterior stabilization with Bankart repair, and Latarjet. J Shoulder Elbow Surg. 2022 Nov;31(11):2358-2365. doi: 10.1016/j.jse.2022.04.017.Epub 2022 May 18. PMID: 35597534.
• Rauck RC, Jahandar A, Kontaxis A, Dines DM, Warren RF, Taylor SA, Gulotta LV. The role of the long head of the biceps tendon in posterior shoulder stabilization during forward flexion. J Shoulder Elbow Surg. 2022 Jun;31(6):1254-1260. doi: 10.1016/j.jse.2021.12.026. Epub 2022 Jan 20. PMID: 35066121.
• Shah SS, Kontaxis A, Jahandar A, Bachner E, Gulotta LV, Dines DM, Warren RF, Dines JS, Taylor SA. Superior capsule reconstruction using a single 6-mm-thick acellular dermal allograft for massive rotator cuff tears: a biomechanical cadaveric comparison to fascia lata allograft. J Shoulder Elbow Surg. 2021 Sep;30(9):2166-2176. doi: 10.1016/j.jse.2020.11.015. Epub 2021 Jan 5. PMID: 33418091.
• Spang RC, Jahandar A, Meyers KN, Nguyen JT, Maher SA, Strickland SM. Dysplastic Patellofemoral Joints Lead to a Shift in Contact Forces: A 3D-Printed Cadaveric Model. Am J Sports Med. 2021 Oct;49(12):3344-3349. doi: 10.1177/03635465211031427. Epub 2021 Aug 20. PMID: 34415194.
• Lamplot JD, Jahandar A, Meyers KN, Gomoll AH, Maher SA, Strickland SM. Anteromedialization Tibial Tubercle Osteotomy Improves Patellar Contact Forces: A Cadaveric Model of Patellofemoral Dysplasia. Am J Sports Med. 2023 Feb;51(2):453-460. doi: 10.1177/03635465221138287. Epub 2022 Dec 1. PMID: 36453729.

For more publications, please see the PubMed listing.

About Clarisse Zigan

Clarisse Zigan joined the Biomechanics Department at HSS in 2023 as a Post Bac Researcher after completing her undergraduate and master’s degrees in Biomedical Engineering from Purdue University. While at Purdue, she enhanced her practical experience in research by leading projects in Dr. Deva Chan’s Lab where she developed bioreactors for in vitro studies of chondrocyte mechanobiology and mechanotransduction in hydrogels and designed an intra-articular ankle fracture device for large animal studies of post traumatic osteoarthritis. 

She is interested in the interplay between tissue specific mechanics as well as whole joint biomechanics in order to contribute to the knowledge gaps needed for implant improvement. Her current research revolves around experimental and robotic work, focused on quantifying the contributions of soft tissues surrounding the hip capsule to determine their influence to the resistance of impingement and dislocation in total hip arthroplasties.

Education

Purdue University, B.S. 2022
Purdue University, M.S. 2023

Awards

Master’s Student Paper Competition Finalist, Summer Biomechanics, Bioengineering, & Biotransport Conference (SB3C), 2023

About David Shamritsky

David’s work in the Biomechanics Department focuses on a clinical research device that measures structural stability of a patient’s knee in response to specific directions of loading. Outputs from this device are being used to aid in diagnosis of soft tissue injuries, evaluate the effectiveness of surgical treatments, and compare post-operative results to intra-operative decision-making. This project is highly collaborative with clinicians and researchers in the Sports Medicine Institute and Adult Reconstruction & Joint Replacement (ARJR) services.

Prior to joining HSS, David received his undergraduate and master’s degrees in Biomedical Engineering from Cornell University. At Cornell, he performed research in Dr. Christopher Hernandez’s lab developing an in-vivo fatigue loading model for the knee to study bone marrow lesions and osteoarthritis. His graduate design project was in partnership with ENT clinicians at Weill Cornell Medicine and in Zimbabwe to design and prototype a medical device that met the needs of their country’s hospital network.

Education

Cornell University, B.S. 2021
Cornell University, M. Eng. 2021

Department of Biomechanics
AMT Center
510 East 73rd Street, Room 202-A
New York, NY 10021

Tel: 212.606.1737
Email: BerubeE@hss.edu

About Erin Berube

Erin Berube joined the Biomechanics Department at HSS in 2019 after graduating with a B.S. in Biomedical Engineering and an M.S. in Biology from Rensselaer Polytechnic Institute. She became interested in orthopedic research while working in Deva Chan’s lab studying models of ACL injury. Erin joined HSS to transition from basic science research to clinical and translational research. She works in collaboration with the Sports and Arthroplasty services to understand knee joint stability.

Her current research focuses on understanding how knee laxity, bony morphology, and quantitative MRI measurements relate to risk of ACL injury and ACL graft healing. The goal of this work is to reduce rates of early graft failure following ACL reconstruction.

She has also studied the effects of surgical decision making on knee laxity and stability in total knee arthroplasty (TKA). This work aims to understand how implant selection affects knee laxity and patient satisfaction following TKA. 

Selected Publications

• Kent RN 3rd, Amirtharaj MJ, Berube EE, Imhauser CW, Thein R, Voleti PB, Wickiewicz TL, Pearle AD, Nawabi DH. Anterior cruciate ligament graft forces are sensitive to fixation angle and tunnel position within the native femoral footprint during passive flexion. Knee. 2021 Dec;33:266-274. doi: 10.1016/j.knee.2021.08.003. Epub 2021 Nov 26. PMID: 34844133. 
• Shamritsky DZ, Berube EE, Sapountzis N, Diaz A, Krell EC, Wright TM, Parides M, Westrich GH, Mayman DJ, Sculco PK, Chalmers BP, Imhauser CW. Novel Arthrometer For Quantifying In Vivo Knee Laxity in Three Planes Following Total Knee Arthroplasty. J Arthroplasty. 2023 Feb 20:S0883-5403(23)00138-9. doi: 10.1016/j.arth.2023.02.030. Epub ahead of print. PMID: 36813213. 
• Razu S, Jahandar H, Zhu A, Berube E, Manzi J, Pearle A, Nawabi D, Wickiewicz TL, Santner T, Imhauser C. Bayesian Calibration of Computational Knee Models to Estimate Subject-Specific Ligament Properties, Tibiofemoral Kinematics, and Anterior Cruciate Ligament Force with Uncertainty Quantification. J Biomech Eng. 2023 Feb 24:1-35. doi: 10.1115/1.4056968. Epub ahead of print. PMID: 36826392

For more publications, please see the PubMed listing.

Department of Biomechanics 

​AMT Center 

​510 East 73rd Street, Room 202-A 

​New York, NY 10021​ 

Email: gomezhjertheni@hss.edu​ 

About Isabella Gomez Hjerthen

Isabella joined the Biomechanics Department at HSS in 2024 as a Post Bac Researcher. Her work focuses on how quantitative imaging, knee laxity, and bony morphology relate to risk of ACL injury and graft failure in ACL reconstruction. This includes developing patient-specific computational knee models and using motion capture to investigate joint biomechanics.

Prior to joining HSS, Isabella received her undergraduate degree in Mechanical Engineering from Harvard University. At Harvard, she performed research in Dr. Shriya Srinivasan’s lab developing a wearable device for spasticity-focused vibration therapy. Isabella was also part of Dr. Farrah Mateen’s Global Neurology Research Group at Massachusetts General Hospital, where her work aimed to understand the impact of neuromyelitis optica spectrum disorder (NMOSD) on the employment of patients living in 23 countries.

Education

B.Sc. - Mechanical Engineering - Harvard University, 2024

Awards

Elsevier – Best Clinical Paper Award of the 26^th World Congress of Neurology (WCN23), October 2023

About Jeff Hoffman

Jeff Hoffman began at HSS as a research engineer in the biomechanics department in March 2019. As a research engineer, he leads testing exploring the biomechanics of the foot and ankle using a validated 6-degree of freedom robotic gait simulator. Currently, he is examining the effect of surgical interventions on a validated model of progressive collapsing foot deformity during walking. Additionally, he is working with clinical staff to evaluate the effect of tibial implant design on early stage micromotion after total ankle arthroplasty. Previously, Jeff has worked on biomechanical projects aimed at addressing common pathologies of the foot and ankle, such as Jones’ fracture and Lisfranc injuries.

In addition to foot and ankle work, Jeff is involved in uniaxial mechanical testing for various projects around the lab. 

Prior to HSS, Jeff received his M.S. in Biomedical Engineering from Drexel University in 2018. During his time at Drexel, he worked in collaboration with the motion laboratory at Shriners Hospital for Children in Philadelphia to evaluate the changes in pediatric spinal motion with age in healthy and scoliotic patients. Jeff received a BS in Biomedical Engineering from the University of Delaware in 2016. During his time at UD, Jeff worked as an undergraduate research assistant to evaluate the effect of functional electrical stimulation during gait in pediatric patients with cerebral palsy. 

Education

BS – University of Delaware, 2016
MS – Drexel University, 2018

Awards

J Leonard Goldner Award, AOFAS Annual Meeting, 2022

Selected Publications

• Hoffman JW, Bitar RC, Williams N, Steineman BD, Sturnick DR, Garrison GW, Demetracopoulos CA, Drakos MC, O'Malley MJ. Orthosis and Foot Structure Affect the Fifth Metatarsal Principal Strains During Simulated Level Walking. Am J Sports Med. 2022 May;50(6):1659-1667. doi: 10.1177/03635465221079652. Epub 2022 Mar 18. PMID: 35302902.
• Kim J, Hoffman J, Steineman B, Eble SK, Roberts LE, Ellis SJ, Drakos MC. Kinematic Analysis of Sequential Partial-Midfoot Arthrodesis in Simulated Gait Cadaver Model. Foot Ankle Int. 2022 Dec;43(12):1587-1594. doi: 10.1177/10711007221125226. Epub 2022 Oct 14. PMID: 36239404.
• Henry JK, Hoffman J, Kim J, Steineman B, Sturnick D, Demetracopoulos C, Deland J, Ellis S. The Foot and Ankle Kinematics of a Simulated Progressive Collapsing Foot Deformity During Stance Phase: A Cadaveric Study. Foot Ankle Int. 2022 Dec;43(12):1577-1586. doi: 10.1177/10711007221126736. Epub 2022 Oct 19. PMID: 36259688.
• Kim J, Hoffman JW, Ellis SJ, Deland JT, Steineman BD. 2022 J. Leonard Goldner Award Winner: Passive Eversion Assessment for Progressive Collapsing Foot Deformity after Lateral Column Lengthening: A Cadaveric Biomechanical Study. Foot & Ankle Orthopaedics. 2022;7(4). doi:10.1177/2473011421S00724

Julianna Villella graduated from Stevens Institute of Technology with a Bachelor of Engineering in biomedical engineering. She works with Dr. Carl Imhauser in the Biomechanics Department, focusing on developing and validating a TKA-specific patient-reported outcome measure (PROM) to improve patient satisfaction following Total Knee Arthroplasty (TKA). She is also involved in a study using a novel knee tester to understand the correlation between objective knee laxity and patient perceptions of instability. Julianna collaborates closely with Dr. Brian Chalmers, who leads the clinical component of this research.

About Kalle Chastain

Kalle grew up near Seattle, Washington where she received her B.S. in Mechanical Engineering at University of Washington in 2018. While at UW, she worked at the Center for Limb Loss and Mobility with Dr. William Ledoux as an undergraduate assistant. She made her way to the Center for Applied Biomechanics at the University of Virginia working with Dr. Jason Kerrigan. During her graduate work, she assisted on projects regarding automotive injury research, with an emphasis on reclined occupants of highly automated vehicles. Her thesis, Characterization of the Mechanical Response of the Lumbar Spine: The Effect of a Compressive Axial Load, focused on characterizing the human lumbar spine for the purpose assessing the fidelity of human body models in motor vehicle crashes. After graduating with her M.S. in Mechanical and Aerospace Engineering in 2021, she found HSS and was hired as a Research Engineer in the Biomechanics department, under Dr. Suzanne Maher.

Kalle’s work is primarily in experimental and robotic work, focusing on contact mechanics of the knee joint. Kalle’s current projects include researching the change in contact mechanics following a partial meniscectomy, and the change in contact mechanics following a tibial osteotomy to realign the tibial plateau. She has previously worked on investigations of contact mechanical changes following a meniscal leaflet tear, and meniscal root tear. She is a member of the Orthopedic Research Society (ORS) and recently attended her first in-person ORS conference.

Education

• Master’s of Science in Mechanical and Aerospace Engineering, 2021; University of Virginia, Charlottesville, VA
• Bachelor’s of Science in Mechanical Engineering, 2018; University of Washington, Seattle, WA

Awards

Best Poster in Meniscus Section, Orthopedic Research Society (ORS) Conference, 2023

Selected Publications

• Chastain, K., Wach, A., Pekmezian, A., Wimmer, M. A., Warren, R. F., Torzilli, P. A., ... & Maher, S. A. (2022). ACL transection results in a posterior shift and increased velocity of contact on the medial tibial plateau. Journal of Biomechanics, 144, 111335.
• Richardson, R., Jayathirtha, M., Chastain, K., Donlon, J. P., Forman, J., Gepner, B., ... & Kerrigan, J. (2020). Thoracolumbar spine kinematics and injuries in frontal impacts with reclined occupants. Traffic injury prevention, 21(sup1), S66-S71.

About Kate Meyers

Kate Meyers works in the dual role of Research Engineer and Lab Manager. She joined HSS after receiving her BS and MS in Biomechanical Engineering from Syracuse University.

She collaborates with clinicians, residents, and fellows across all surgical services to bolster their biomechanics acumen while furthering their research interests. Kate’s expertise is in experimental design with recent research focused on spine and hip kinematics, hip arthroplasty, and wrist and elbow stability. 

As the Lab Manager, she explores new technologies to further the capabilities of the research group, trains engineers and students on both equipment and experimental methods, directs core mechanical testing needs for the department, and acts as a primary contact for surgeon-driven research.

Kate has been a member of the Orthopedic Research Society since 2006 and reviews for various journals including Journal of Orthopaedic Surgery and Research.

Selected Publications

• Meyers KN, Middleton KK, Fu MC, Dines JS. Comparison of a Novel Anatomic Technique and the Docking Technique for Medial Ulnar Collateral Ligament Reconstruction. Am J Sports Med. 2022 Mar;50(4):1061-1065. [PMID:35188812]
• Quevedo González FJ, Meyers KN, Schraut N, Mehrotra KG, Lipman JD, Wright TM, Ast MP. Do Metaphyseal Cones and Stems Provide Any Biomechanical Advantage for Moderate Contained Tibial Defects in Revision TKA? A Finite-Element Analysis Based on a Cadaver Model. Clin Orthop Relat Res. 2021 Nov 1;479(11):2534-2546. [PMID: 34351312]
• Burnier M, Jethanandani R, Pérez A, Meyers K, Lee S, Wolfe SW. Comparative Analysis of 3 Techniques of Scapholunate Reconstruction for Dorsal Intercalated Segment Instability. J Hand Surg Am. 2021 Nov;46(11):980-988 [PMID: 34332817]
• Virk S, Meyers KN, Lafage V, Maher SA, Chen T. Analysis of the influence of species, intervertebral disc height and Pfirrmann classification on failure load of an injured disc using a novel disc herniation model. Spine J. 2021 Apr;21(4):698-707. [PMID: 33157322]

For more publications, please see the PubMed listing.

About Sara Sacher

Sara Sacher joined the Biomechanics Department at HSS in 2023. She is currently managing the implant retrieval system and overseeing subsequent research projects. Research focus areas include mechanical characterization of implant materials, failure analysis, and clinical implications of such findings. 

Prior to this role, Sara was a research engineer in the MRI Lab in the department of Radiology at HSS. In the MRI lab, the focus of Sara’s research was the development of novel quantitative imaging techniques to evaluate tissue pathology after total joint arthroplasty. Prior to joining HSS, Sara earned her B.S. and M.S. degrees in materials science and engineering from Virginia Tech and Cornell University, respectively. At Cornell, Sara worked under the guidance of Dr. Eve Donnelly, where she investigated the mechanisms behind skeletal fragility in patients with type II diabetes. At Virginia Tech, Sara worked in an additive manufacturing research lab evaluating the effects of thermal and morphological characteristics on material printability. 

Education

Virginia Tech, B.S. in Materials Science and Engineering, 2019
Cornell University, M.S. in Materials Science and Engineering, 2021

Awards

HSS 1st Annual Research Day Presentation Award, 2023
Kappa Delta / American Academy of Orthopaedic Surgeons Travel Award, 2020

Selected Publications

Sacher SE, Koff MF, Tan ET, Burge A, Potter HG. The role of advanced metal artifact reduction MRI in the diagnosis of periprosthetic joint infection. Skeletal Radiol. 2023 Oct 24. doi: 10.1007/s00256-023-04483-5. PMID: 37875571.

Sacher SE, Neri JP, Gao MA, Argentieri EC, Potter HG, Koch KM, Koff MF. MAVRIC based T2 mapping assessment of infrapatellar fat pad scarring in patients with total knee arthroplasty. J Orthop Res. 2023 Jun;41(6):1299-1309. doi: 10.1002/jor.25472. Epub 2022 Nov 6. PMID: 36262013; PMCID: PMC10113607.

Sacher SE, Hunt HB, Lekkala S, Lopez KA, Potts J, Heilbronner AK, Stein EM, Hernandez CJ, Donnelly E. Distributions of Microdamage Are Altered Between Trabecular Rods and Plates in Cancellous Bone From Men With Type 2 Diabetes Mellitus. J Bone Miner Res. 2022 Apr;37(4):740-752. doi: 10.1002/jbmr.4509. Epub 2022 Feb 15. PMID: 35064941; PMCID: PMC9833494.

For more publications, please see the Pubmed Listing

Department of Biomechanics
AMT Center
510 East 73rd Street, Room 202-A
New York, NY 10021

Tel: 646.797.8532
Email: mountcastles@hss.edu

About Sydney Mountcastle

Sydney joined the Biomechanics department at HSS in August 2025. The focus of her work is primarily the development and implementation of a new gait analysis pipeline using a Markerless motion capture system. This pipeline will allow for large volumes of patients to receive gait analysis in the clinical setting, so that gait kinematics and kinetics can be more easily understood and evaluated for patient care. For this project, Sydney collaborates with clinicians in the Adult Reconstruction & Joint Replacement services, and researchers in the Biomechanics Department.

Prior to joining HSS, Sydney received her bachelor’s and master’s degrees in Biomedical Engineering at Case Western Reserve University. At CWRU, Sydney worked at the Advanced Platform Technology Center at the Louis Stokes Cleveland VA Medical Center, focusing on the development of wearable exoskeletons for restoring mobility in stroke survivors and individuals with spinal cord injury. As an undergraduate intern, she worked under Dr. Sandra Hnat on the design, manufacturing, and testing of an exoskeleton model to be used for crash testing. For her graduate work, Sydney worked under Dr. Nathaniel Makowski on her thesis, A Characterization of the Effects of Exoskeleton Misalignment. Her thesis involved gait analysis, and exoskeleton design recommendations and implementation to improve fitment and alignment of exoskeleton devices.

Education

• Master’s of Science in Biomedical Engineering, 2025; Case Western Reserve University, Cleveland, OH
• Bachelor’s of Science in Biomedical Engineering, 2024; Case Western Reserve University

Department of Biomechanics
AMT Center
510 East 73rd Street, Room 202-H
New York, NY 10021

TEL: 212.606.1420
Email: lipmanj@hss.edu

After receiving and undergraduate and master’s degree in mechanical engineering from Tufts University, Mr. Lipman joined the Biomechanics Department as a Design Engineer.

He has over 33 years of medical research and device development experience and has been the Director of Device Development since 2000.  He has worked with multiple services at HSS including Adult Hip and Knee Replacement, Foot and Ankle, Hand and Upper Extremity, Hip Preservation, Spine and Sports Medicine.  In working with these services and the Biomechanics department, he’s contributed to the development of implants for the knee, hip, elbow, wrist and spine. These implants have been licensed to several orthopaedic companies and are sold worldwide. He is a named inventor on twenty-six US patents and has multiple publications in the medical device area. In addition, he is a registered US Patent Agent.

He is the recipient of the 2019 AAOS Orthopaedic Video Theater Award – Adult Reconstruction Hip, the 2011 AOSSM Excellence in Research Award and the 1998 ASB Clinical Biomechanics Award. He is a reviewer for JOR, CORR, JBJS, Scientific Reports and the HSS journal. 

Selected Publications

Scifert CF, Brown TD, Lipman JD. Finite element analysis of a novel design approach to resisting total hip dislocation. Clin Biomech (Bristol, Avon). 1999 Dec;14(10):697-703.

Maher SA, Lipman JD, Curley LJ, Gilchrist M, Wright TM. Mechanical performance of ceramic acetabular liners under impact conditions. J Arthroplasty. 2003 Oct;18(7):936-41.

Huang RC, Wright TM, Panjabi MM, Lipman JD. Biomechanics of nonfusion implants. Orthop Clin North Am. 2005 Jul;36(3):271-80.

Holley KG, Furman BD, Babalola OM, Lipman JD, Padgett DE, Wright TM. Impingement of acetabular cups in a hip simulator: Comparison of highly cross-linked and conventional polyethylene. J Arthroplasty. 2005 Oct;20(7 Suppl 3):77-86.

Maher SA, Lipman JD. Influence of acetabular rim profile on hip dislocation. Proceedings of the I MECH E Part H Journal of Engineering in Medicine. 2006;220(8):881-6.

For more publications, please see the PubMed listing.

Recent Presentations

Lipman JD, Padgett DE, Robie BH. How total hip component design influences range of motion and dislocation rate. Trans Orthop Res Soc. 1998:830.

Furman BD, Holley K, Babalola OM, Lipman JD, Haywood AM, Padgett DE, et al. Acetabular component impingement increases wear and damage of elevated crosslinked and conventional UHMWPE. Trans Orthop Res Soc. 2004:7-10.

Gortner MR, Lipman JD, Wright TM, Bartel DL. Finite element analysis of anterior post impingement on posterior stabilizing total knee prostheses. Trans Orthop Res Soc. 2006.

About Ritvik Sarkar

Ritvik Sarkar studied in Cornell University with an interest in medical device design. While working in Christopher Hernandez’s lab to design a platform to test the mechanical properties of bacterial cell walls, Ritvik became interested in the lab’s other work in orthopedics. After graduating from Cornell in 2017 with a B.S. and M.Eng. in Mechanical Engineering, he joined the Device Development group within Hospital for Special Surgery’s Department of Biomechanics.

Ritvik works closely with both HSS surgeons and orthopedic implant manufacturers to design patient specific implants for complex primary and revision hip and knee replacements. He also designs and develops new implant systems that address challenging clinical problems in the hip and upper extremity.

Education

Masters of Engineering in mechanical engineering, Cornell University, 2017
Bachelors of Science in mechanical engineering, Cornell University, 2016

About Ryan Helbock

Ryan Helbock joined HSS in 2022 as a Design Engineer in the Device Development group, where he works on patient-specific preoperative planning and custom implant design for complex joint arthroplasty. He is also involved in computational research studying how implant design and bone quality can contribute to early failure of total hip replacements. 

Prior to joining HSS, Ryan received his BE and MS degrees in Biomedical Engineering at Stony Brook University in 2020 and 2022, respectively. During his graduate studies, he conducted research on cardiovascular implants and designed a novel transcatheter aortic valve replacement via patient-specific computational modeling. His interest in solving complex problems involving the human body is what drew him to the multifaceted and bustling Biomechanics Department at HSS

Education

2022, Master of Science in biomedical engineering, Stony Brook University
2020, Bachelor of Engineering in biomedical engineering, Stony Brook University

Selected Publications

• Helbock RT, Anam SB, Kovarovic BJ, Slepian MJ, Hamdan A, Haj-Ali R, Bluestein D. Designing a Novel Asymmetric Transcatheter Aortic Valve for Stenotic Bicuspid Aortic Valves Using Patient-Specific Computational Modeling. Ann Biomed Eng. 2023 Jan;51(1):58-70. doi: 10.1007/s10439-022-03039-3. Epub 2022 Aug 30. PMID: 36042099.
• Kovarovic B, Helbock R, Baylous K, Rotman OM, Slepian MJ, Bluestein D. Visions of TAVR Future: Development and Optimization of a Second Generation Novel Polymeric TAVR. J Biomech Eng. 2022 Jun 1;144(6):061008. doi: 10.1115/1.4054149. PMID: 35318480; PMCID: PMC8990719.

For more publications, please see the PubMed listing.

About Yupin Shi

Yupin Shi joined Hospital for Special Surgery (HSS) Department of Biomechanics in August 2021 as a design engineer in the device development group. Her work focuses on patient implant design including total hip, knee, and elbow replacement. She also uses finite element methods (FEM) to study implants and bone-implant interactions. In addition, she helps with the development of implant systems that will be licensed to orthopaedic companies.

Yupin was born and raised in China. She received her B.S. degree from Lehigh University in Pennsylvania and M.S. degree from Johns Hopkins University (JHU) in Maryland both in Mechanical Engineering. At Lehigh, she was a research assistant in Dr. Natasha Vermaak’s lab where she simulated wear motion and thermal effect on different bi-material composites with FEM. During her study at JHU, she joined Dr. Vicky Nguyen’s lab and numerically simulated the locomotion of a thermo-reactive bilayer soft gel robot with non-linear FEM. In the last semester of her graduate study, she worked as a R&D Mechanical Engineering intern at Relavo, a JHU student startup medical device company that is developing a disinfection device for home peritoneal dialysis treatment. 

Yupin wants to use her expertise in implant design and biomechanics to contribute to the healthcare industry.

Education

2019, Bachelor of Science, Mechanical Engineering, Lehigh University.
2021, Master of Science, Mechanical Engineering, Johns Hopkins University.

Selected Publications

• Pantula A, Datta B, Shi Y, Wang M, Liu J, Deng S, Cowan NJ, Nguyen TD, Gracias DH. Untethered unidirectionally crawling gels driven by asymmetry in contact forces. Science Robotics. 2022 Dec 14;7(73):eadd2903.
• Grejtak T, Jia X, Feppon F, Joynson SG, Cunniffe AR, Shi Y, Kauffman DP, Vermaak N, Krick BA. Topology Optimization of Composite Materials for Wear: A Route to Multifunctional Materials for Sliding Interfaces. Advanced Engineering Materials. 2019 Aug 1;21(8).
• Grejtak T, Jia X, Cunniffe AR, Shi Y, Babuska TF, Pack RC, Vermaak N, Compton BG, Krick BA. Whisker orientation controls wear of 3D-printed epoxy nanocomposites. Additive Manufacturing. 2020 Dec 1;36:101515.