The Use of Advanced Semiautomated Bone Segmentation in Hallux Rigidus.



Weightbearing computed tomography (WBCT) measurements allow evaluation of several anatomical points for a correct clinical-radiographic diagnosis of pathologies, such as hallux rigidus (HR). In addition, a new semiautomatic segmentation software obtains automated 3D measurements from WBCT scan data sets, minimizing errors in reading angular measurements. The study's objective was (1) to evaluate the reliability of WBCT semiautomatic imaging measures in HR, (2) to evaluate correlation and agreement between manual and semiautomatic measures in the setting of HR, and (3) to compare semiautomatic measurements between pathologic (HR) and standard control groups.


A retrospective study of HR patients was performed including 20 feet with HR. WBCT manual and semiautomatic 3D measurements were performed using the following parameters: (1) first metatarsal-proximal phalanx angle (1stMPP), (2) hallux valgus angle (HVA), (3) first to second intermetatarsal angle (IMA), (4) hallux interphalangeal angle (IPA), (5) first metatarsal length (1stML), (6) second metatarsal length (2ndML), (7) first metatarsal declination angle (1stMD), (8) second metatarsal declination angles (2ndMD), and (9) metatarsus primus elevatus (MPE). The differences between pathologic and control cases were assessed with a Wilcoxon test.


Interobserver and intraobserver agreement for manual vs semiautomatic WBCT measurements demonstrated excellent reliability. According to the Pearson coefficient, there was a strong positive linear correlation between both methods for the following parameters evaluated: HVA (ρ = 0.96), IMA (ρ = 0.86), IPA (ρ = 0.89), 1stML (ρ = 0.96), 2ndML (ρ = 0.91), 1stMD (ρ = 0.86), 2ndMD (ρ = 0.95), and MPE (ρ = 0.87). Comparison between the pathologic group with HR and the control (standard) group allowed for the differentiating of the pathologic (HR) from the non-pathologic conditions for MPE (p < 0.05).


Semiautomatic measurements are reproducible and comparable to measurements performed manually, showing excellent interobserver and intraobserver agreement. The software used differentiated pathologic from nonpathologic conditions when submitted to semiautomatic MPE measurements.

Level of evidence

Level III, retrospective comparative study.





Published Version (Please cite this version)


Publication Info

de Carvalho, Kepler Alencar Mendes, Vineel Mallavarapu, Amanda Ehret, Kevin Dibbern, Hee Young Lee, Nacime Salomao Barbachan Mansur, Matthieu Laleveé, Cesar de Cesar Netto, et al. (2022). The Use of Advanced Semiautomated Bone Segmentation in Hallux Rigidus. Foot & ankle orthopaedics, 7(4). p. 24730114221137597. 10.1177/24730114221137597 Retrieved from

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de Cesar Netto

Cesar de Cesar Netto

Instructor in the Department of Orthopaedic Surgery

The desire to explore, research, and understand things in great detail has been the driving force throughout my career. This passion drew me to Foot and Ankle, a subspecialty expanding in orthopedic knowledge with many unsolved mysteries. After completing my Medical School, Orthopedic Residency, and Foot and Ankle Fellowship at the renowned University of Sao Paulo, ranked number one in Latin America for several years, and after five years of clinical practice in Brazil, this desire to explore and understand also brought me to the United States. As part of my Ph.D. program with the University of Sao Paulo, I joined as a visiting scientist and research fellow for Dr. Lew Schon at the traditional MedStar Union Memorial Hospital in Baltimore-MD, where I developed an animal model of induced Achilles tendinopathy. 

As a practicing physician in Brazil, I achieved multiple goals in my early career. Academics have been a large component of my practice, allowing me to participate in young physicians' education and challenge my understanding of orthopedic fundamentals. As the elected Chief of Orthopaedic Residents from 2011 to 2013, I presented 245 lectures to orthopedic surgeons and in multidisciplinary conferences. My practice as an orthopedic surgeon in Sao Paulo allowed me to combine the Brazilian enthusiasm for soccer, serving as the team physician and Foot and Ankle advisor for the professional soccer team Sport Club Corinthians Paulista for almost five years.

As a Foot and Ankle surgeon, I constantly sought to confront the unsolved questions in our orthopedic practices. During my Ph.D. studies with the University of Sao Paulo, I aimed to maximize my research experience and clinical exposure. During my time in Maryland, I have engaged in multiple research projects, collaborating with MedStar Union Memorial and Johns Hopkins University to evaluate and clinically implement innovative imaging techniques, including weight-bearing CT, dynamic CT, 3D MRI, and metal artifact reduction sequence (MARS) MRI.

I was also amazed by the American medical system's resources that create opportunities for motivated physicians to excel in clinical work, educational teaching endeavors, and research investigations. While this balance requires dedication and precise time management, I have been fortunate to work with a variety of mentors who demonstrated to me how great it could be to practice in the US. With that in mind, I ended up deciding to pursue the Academic Pathway of the ABOS Certification. I have completed a total of three Orthopedic Foot and Ankle Fellowships in the US. The first was at the University of Alabama at Birmingham (UAB), the second at the Hospital for Special Surgery (HSS) in New York City, and the third and final at MedStar Union Memorial Hospital in Baltimore-MD. It was a long but very pleasant and rewarding pathway that allowed me to grow as a person, as a clinician, and as a surgeon while being fortunate to create lifetime bonds with several mentors. Once I was done with my fellowships, my objective was to combine my unique background with my innovative and instructive training and apply the acquired knowledge as an Academic Assistant Professor at the Department of Orthopedics of the Carver College of Medicine at the University of Iowa.

The almost four years in Iowa City have been a blast! The leadership of the Orthopedic Department entirely and constantly supported me, and together, we achieved a lot in a relatively short amount of time. I utilized my academic start-up grant to acquire the first Weight-Bearing CT scanner in the Country that allows the hip, knee, foot, and ankle to be scanned under load simultaneously. With the scanner, I founded and served as the Director of the University of Iowa Orthopedic Functional Imaging Research Laboratory (OFIRL), which rapidly achieved an established, recognized position in the research and orthopedic foot and ankle community. I also had the unique opportunity to care for the State of Iowa community suffering from orthopedic foot and ankle problems, always excelling in providing high-quality and passionate clinical and surgical care. I’ll be forever grateful to my leadership, partners, and colleagues in Iowa City, as well as my patients, who gave me the utmost opportunity to care for them.

As an Associate Professor in the Department of Orthopedics at Duke University, I hope to contribute further to the American society and North Carolina Community, taking excellent care of patients, teaching and mentoring medical students, residents, and fellows, and helping the orthopedic foot and ankle surgery research to excel.

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