My research focuses on biomechanics, tissue engineering, and quantitative analysis of medical devices and biomaterials.

Accepted Conference Presentation · 2027

Quadriceps Tendon Autograft Donor-Site Closure Increases Patellofemoral Contact Pressures: A Cadaveric Study

Badin D, Nicholls L, Le Y, Elsabbagh Z, Glenn E, Middendorf JM, Lee RJ.

Johns Hopkins University
Department of Mechanical Engineering & Department of Orthopaedic Surgery

Conference Presentations
PRiSM 2027, 14th Annual Meeting
Biomechanics Session, Abstract #31
January 28, 2027 | Orlando, FL

Maryland Orthopaedic Association Annual Meeting
Accepted for poster presentation

View Research Paper
Cadaveric patellofemoral biomechanics experimental setup
Experimental setup for evaluating patellofemoral contact mechanics using cadaveric knee specimens and thin-film pressure sensors.

Research Overview

Quadriceps tendon autografts are increasingly used in anterior cruciate ligament (ACL) reconstruction, but postoperative anterior knee pain remains a concern. This study investigated how quadriceps tendon graft harvesting and subsequent donor-site closure affect patellofemoral joint biomechanics.

Using eight fresh-frozen cadaveric lower-extremity specimens, we measured patellofemoral contact pressure and contact area across five knee flexion angles (0°, 30°, 60°, 90°, and 110°). Thin-film Tekscan sensors were used to quantify changes between the native knee, post-harvest condition, and loose and tight donor-site closure.

Patellofemoral contact pressure heat maps
Representative patellofemoral contact pressure distributions demonstrating increased joint loading following loose and tight donor-site closure, particularly at higher knee flexion angles.

Key Findings

Quadriceps tendon harvesting alone did not increase patellofemoral contact pressures. However, both loose and tight closure of the donor-site defect significantly increased joint contact pressures, particularly at higher flexion angles.

At 110° of knee flexion, median peak contact pressure increased from 47.2 PSI at baseline to 82.0 PSI following tight closure, a roughly 74% increase. Contact area did not significantly change across experimental conditions.

These findings suggest that donor-site closure may alter patellofemoral loading following ACL reconstruction and could contribute to postoperative anterior knee symptoms. Further clinical research is needed to establish the relationship between these biomechanical changes and patient outcomes.

My Contributions

As a mechanical engineering researcher, I contributed to the development and execution of the experimental biomechanics testing methodology, including:

  • Preparation and calibration of Tekscan thin-film pressure sensors using mechanical testing equipment.
  • Development and refinement of experimental setups for cadaveric knee testing.
  • Collection and analysis of patellofemoral contact pressure measurements across knee flexion angles and surgical conditions.
  • Troubleshooting experimental loading, sensor alignment, and measurement consistency to support reliable biomechanical testing.

Technical Skills

Experimental Biomechanics Cadaveric Testing Tekscan Pressure Mapping Instron Testing Sensor Calibration Data Analysis Orthopaedic Research

Conference Citation

Badin D, Nicholls L, Le Y, Elsabbagh Z, Glenn E, Middendorf JM, Lee RJ. Quadriceps tendon autograft donor-site closure increases patellofemoral contact pressures: a cadaveric study. Podium presentation (Abstract #31), Biomechanics Session. PRiSM 2027, 14th Annual Meeting; January 28, 2027; Orlando, FL.

Bioinspired Structural Heterogeneity Directs Host Remodeling and Limits Intimal Hyperplasia in Small-Diameter Vascular Grafts

Accepted for publication · Journal information coming soon

Marianna Barbuto, Arianna Adamo, Beatrice Di Caccamo, Laura Modica De Mohac, Taro Fujii, Keishi Kohyama, William D'Angelo, Tara Richards, Carlo Mannina, Amber Wish, Lance Nicholls, Salma O. El-Mossier, Seungil Kim, George Hussey, Stephen F. Badylak, William R. Wagner, Julie A. Phillippi, and Antonio D'Amore

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Overview of three-layer vascular graft configurations
Featured figure showing the ACR and ICR three-layer vascular graft configurations, including schematic design, macroscopic evaluation, microscopic evaluation, and suture retention testing.

Project Overview

Small-diameter vascular grafts are used to replace damaged blood vessels, but current synthetic grafts often fail because they are susceptible to thrombosis, intimal hyperplasia, and poor long-term patency. This project developed a biomimetic three-layer vascular graft designed to recreate the layered architecture of native arteries and direct host cell infiltration during healing.

The graft combined electrospun polymers with decellularized extracellular matrix to create structural gradients that encouraged healthy tissue remodeling. When implanted in a rat abdominal aorta model, the bioinspired design demonstrated improved endothelialization, greater collagen deposition, enhanced microvascular formation, and maintained 100% patency through eight weeks.

My Contributions

I developed computational tools that enabled quantitative evaluation of both the biological remodeling and mechanical performance of the tissue-engineered vascular grafts.

  • Developed and optimized custom MATLAB scripts to automate quantitative analysis of more than 2,700 histological images.
  • Quantified scaffold remodeling, calcification, cell infiltration, and tissue composition from microscopy images.
  • Developed MATLAB analysis tools to compare the mechanical compliance of tissue-engineered grafts with native rat vessels.
  • Supported quantitative data analysis used to evaluate relationships between scaffold architecture and in vivo remodeling outcomes.

Engineering Skills

MATLAB Image Processing Histological Image Analysis Biomechanics Tissue Engineering Mechanical Characterization Quantitative Data Analysis

Why This Research Matters

One of the greatest challenges in tissue engineering is designing biomaterials that actively guide the body's natural healing process rather than simply replacing damaged tissue. This work demonstrates that engineering structural gradients within vascular grafts can influence how cells repopulate implanted materials, ultimately improving long-term performance.