Global Research for Advanced Visualization and Enabling Technologies Lab (GRAV-ET)

Principal Investigator

Cesar de Cesar Netto

Associate Professor of Orthopaedic Surgery

Principal Investigator

Cesar de Cesar Netto

Associate Professor of Orthopaedic Surgery

Principal Investigator

Cesar de Cesar Netto

Associate Professor of Orthopaedic Surgery

About the Lab

The GRAV-ET Orthopaedics Lab, led by Dr. Cesar De Cesar Netto, MD, PhD, is dedicated to advancing foot and ankle care through cutting-edge translational and clinical research. Our work integrates state-of-the-art imaging, computational modeling, and advanced analytics to study lower extremity biomechanics during functional, weight-bearing activities. Using Weight-Bearing CT (WBCT) and 3D reconstructions, we accurately characterize alignment and deformity, complemented by tools such as plantar pressure mapping, dynamic gait analysis, and 3D printing for preoperative planning and patient-specific orthotics.

We also apply machine learning and predictive modeling to enhance diagnostic precision and identify markers of deformity progression. Clinically, our research spans retrospective and prospective studies on conditions such as Progressive Collapsing Foot Deformity (PCFD), multidirectional ankle instability, sports-related injuries, Hallux Valgus, midfoot and ankle arthritis, and other complex pathologies. By uncovering patient- and treatment-related factors that influence outcomes, we aim to inform evidence-based decisions and enable personalized care.

Our international, multidisciplinary team of surgeons, trainees, and scientists collaborates to bridge biomechanical modeling with clinical applications, delivering innovative solutions that elevate standards of care worldwide.

Research

Progressive Collapsing Foot Deformity (PCFD)

Progressive Collapsing Foot Deformity—formerly known as adult-acquired flatfoot or PTTD—is a complex, three-dimensional condition marked by collapse of the medial longitudinal arch, hindfoot valgus, forefoot abduction, and midfoot varus. This deformity results from failure of the posterior tibial tendon and key supporting ligaments, including the spring, deltoid, and talocalcaneal interosseous ligaments. PCFD affects approximately 5 million people in the U.S. and is staged based on flexibility and severity. Early stages may respond to orthoses, bracing, and physical therapy, while advanced cases often require surgical reconstruction or fusion. Weight-bearing CT and MRI are essential for accurate diagnosis and staging.

Multidirectional Ankle Instability

This condition involves symptomatic instability in two or more directions of ankle motion, often due to combined laxity of the medial and lateral ligaments and/or chronic syndesmotic injury. Unlike isolated lateral instability, surgical treatment typically addresses medial, lateral, and syndesmotic insufficiency. Patients commonly report persistent “giving way,” recurrent sprains, and functional limitations despite conservative care. Functional instability may also involve proprioceptive or neuromuscular deficits, even in the absence of mechanical laxity.

Hallux Valgus (Bunions)

Hallux valgus—commonly called a bunion—is a progressive deformity of the first ray, characterized by medial deviation of the first metatarsal and lateral rotation/pronation of the hallux. It presents as a painful prominence at the medial MTP joint and may be associated with hammertoes, calluses, and sesamoid shift. Risk factors include narrow or high-heeled footwear, genetics, abnormal biomechanics, and inflammatory conditions such as rheumatoid arthritis. Diagnosis relies on a clinical examination and weight-bearing radiographs to measure the hallux valgus angle (HVA) and intermetatarsal angle (IMA). Treatment ranges from footwear modifications and orthoses to surgical correction, tailored to the severity of the deformity.

Research Techniques

Weight-Bearing CT (WBCT)
WBCT is a transformative imaging technology that captures accurate 3D measurements of the lower limb in a natural weight-bearing stance. At GRAV-ET, WBCT is central to our research, enabling precise assessment of alignment and deformity. Our lab utilizes the CurveBeamAI HiRise scanner, which provides comprehensive lower-limb imaging from toe tips to hips, supporting advanced modeling and surgical planning.

Advanced Visualization
Advanced visualization enhances the diagnostic capabilities of WBCT combined with sophisticated 3D techniques in Computer Science to offer new insights into bone and joint physiology and pathology. Techniques such as Artificial Intelligence (AI) and Machine Learning (ML) are utilized. The Grav-ET lab is equipped with Disior software (https://www.disior.com/), which provides the research team with segmentation and advanced visualization tools, including distance measurement, coverage mapping, and automated 3D measurements. Hounsfield Unit (HU) analysis allows the study of local variations in Bone Mineral Density (BMD), named after Sir Godfrey Hounsfield, Nobel Prize winner for the invention of CT.

3D Printing

Our lab leverages 3D printing technology to create precise, patient-specific models of complex foot and ankle deformities. These models support preoperative planning, intraoperative guidance, and educational training, allowing surgeons to rehearse intricate procedures and improve surgical accuracy.

Surgical Planning

We provide clinicians and researchers with advanced visualization tools and 3D measurements to enable patient-specific surgical planning, ensuring tailored and effective treatment strategies.

Custom 3D-Printed Insoles

Custom orthotic insoles—developed from pressure mapping and 3D scanning—are designed to correct biomechanical abnormalities, redistribute plantar pressures, and relieve pain in conditions such as PCFD and hallux valgus.Our lab uses technology from T-Soles, which uniquely integrates pressure scan data with WBCT imaging to create insoles customized to each patient’s bony anatomy. Research evaluates their effectiveness through quantitative gait and pressure analysis.

Pressure Scans

Pressure scanning provides detailed insights into plantar load distribution, identifying abnormal pressure zones and gait asymmetries. This technique facilitates the diagnosis of functional impairments, planning of surgical corrections, and evaluation of postoperative outcomes.

3D Gait Analysis

Three-dimensional gait analysis precisely measures foot and ankle motion during walking, revealing subtle biomechanical deviations linked to deformities or instability. It helps tailor treatment strategies and objectively evaluate surgical outcomes.

Anatomical Specimens Lab

Our cadaveric specimen lab enables biomechanical testing and anatomical validation of new surgical techniques and implant designs. By replicating clinical scenarios in a controlled setting, we generate critical evidence to support innovation in foot and ankle surgery.