A CT-based method to compute femur remodelling after total hip arthroplasty

ABSTRACT

Bone remodelling after total hip arthroplasty has been largely observed and investigated. Most studies rely on projective images and only few obtain 3D information with limited spatial resolution. This study proposes a method to provide quantitative, 3D high-resolution data about femur bone density variations, by means of CT volume processing. This would offer a tool for further research and clinical studies. Five patients subjected to primary, cementless total hip arthroplasty were considered. Calibrated CT volumes were acquired before, just after surgery and 1 yr later. Bone remodelling hinders accurate alignment of femur volumes acquired after a year; instead, prosthesis stem remains unchanged. Thus, after metal artefact reduction, prosthesis was segmented, and stem-based accurate alignment was obtained. A test to exclude prosthesis migration was performed by considering specific femur anatomical landmarks. Bone density error due to artefact reduction and realignment was estimated. Quantitative differences in bone mineral density were computed for each voxel, providing a resolution of about 1 mm. Preliminary results showed that the femur underwent consistent remodelling after a year. Widespread bone density losses appeared in those areas where strain-adaptive remodelling is normally expected, particularly about the calcar. Conversely, distal areas with clear stem-bone contact showed considerable density gains.

KEYWORDS:

• Total hip arthroplasty
• femur bone remodelling
• CT image processing
• prosthesis rigid realignment

Acknowledgments

Authors are thankful to Dr Jonathan Pitocchi and Dr Andrea Menichetti who contributed to some stages of this project.

Ethical approval

VSN 13-127-S1

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

L. Iuppariello

Luigi Iuppariello background is in Biomedical Engineering comprising a BSc and MSc in Biomedical Engineering cum laude from University of Naples, Federico II.  Moreover, he is Ph.D. degree in Electronics and telecommunication engineering at University of Naples, Federico II. Now he is a biomedical engineer at the Santobono-Pausilipon Children’s Hospital. His principle research interests regard the Clinical Engineering, the application of 3D printing in the surgical planning, the kinematic and dynamic models for the motor control in healthy and pathological children, algorithms for the assessment of the muscles activation during walking, reaching movements and robot-mediated therapy.  He was teaching assistant for the course of Health Management and Elaboration of Biomedical Images, Signals and Data and tutor in the development of degree theses. He has been speaker in many scientific national and international conferences, as documented from the scientific publications.

Luca Esposito

Luca Esposito took PhD in Structural Engineering in 2013 at the University of Napoli “Federico II” (Italy). He was 4 years post-doctoral research fellow at the Department of Structures for Engineering and Architecture at the University of Napoli “Federico II”. Since 2013, he was an adjunct professor at the master degree of Materials Engineering, and teaching assistant at the master degrees of Structural Engineering and Biomedical Engineering at the University of Napoli “Federico II”. In 2018, he was an invited professor at the University of Reykjavik. He works currently as a Researcher at the Department of Engineering of the University of Campania “Luigi Vanvitelli” (Italy). He participated in different national and international research projects and is author of more than 50 scientific papers, presented at Conferences, or published into specialised journals.

P. Gargiulo

Paolo Gargiulo is a full Professor and works at center of Medical Technology Center - Reykjavik University /University Hospital Landspitali. He studied at TU Wien and finished his PhD in 2008. Paolo interests and expertise are mostly in: Medical Image processing, Neuroengineering, 3-D printing and Medical technologies. He developed at Landspitali a 3D-Printing service to support surgical planning with over 200 operation planned with a significant impact on the Icelandic health care system and he currently cooperate with institutions in Italy and UK to establish similar infrastructures. He has been a consultant for MedEl (from 2010 to 2016) for the development of larynx pacemaker. Since December 2013 Paolo Gargiulo is the director of the Institute of Biomedical and Neural Engineering

M. K. Gíslason

Dr. Gislason obtained is PhD in computational biomechanics, focussing on finite element analysis of the load transmission through wrist joint, from Strathclyde Univeristy in 2008. In 2013 he was appointed an Assistant Professor at Reykjavik Univeristy and Associate Professor at the same university in 2018. Throughout his research carried, Dr. Gislason has focussed on research in biomechanics, ranging from bone material assessment in osteoporotic SCI subjects and biomechanical assessment of total hip arthroplasty patients to kinematic measurements on head and neck movements.

H. Jónsson

Halldór Jónsson jr. is Head of Orthopaedic Department Landspitali University Hospital Reykjavík and Professor and Chairman of Orthopaedics, Medical Faculty, University if Iceland, Reykjavik. Also Chairman and Head Surgeon for Sarcoma and Central Registry – IceSG (Icelandic Sarcoma Group) Reykjavík and Chairman Orthopaedic Working Group SSG (Scandinavian Sarcoma Group) - Lund, Sweden. Graduated from Uppsala University with PhD in Orthopaedics 1992 on “Soft-Tissue Injuries and Fractures of the Cervical Spine”. Post doctoral researcher at the Department of Orthopaedics, Academic Hospital in Uppsala on pathoanatomy of the metastatic spine and post-operative findings in spine specimens using the Uppsala cryoplaning technique. Morover clinical research on soft tissue injuries and fractures of the cervical spine in cooperation with the University of Iceland and Brisbane in Australia. During the last 15 years cooperation with the University of Reykjavik, School of Science and Engineering on computational orthopaedics and biomechanics in 3D modelling of orthopaedic problems, mostly soft tissue and bone tumors and also on muscle and bone form, size and strength. Over 25 publications in the field of pathoanatomy and clinical research on the spine for both metastasis and trauma,  over 15 publications in the field of clinical research on hip arthrosis and arthroplasty and over 20 publications in the field of computational orthopaedics and biomechanics on the hip with a total citations according to Google of 2291, h-index 25 and i10-index 36. Granted several student awards for teaching and member of the Orthopaedic Societies and Institutes in both Uppsala Sweden and Reykjavík Iceland. The two main goals to day are firstly to find a device to measure the strength of the proximal femur bone for more secure results in future hip arthroplasty and secondly, in cooperation with GENIS (which is a biotechnology company, headquartered in Siglufjörður, Iceland, producing chitosan for two decades), to discover and hopefully develop life changing products, a medical device, with the intention of providing life altering benefits in terms of better bone quality in the elderly population. 

A. Sarno

Antonio Sarno received his master degree in Biomedical Engineering at University of Naples “Federico II” (Italy) in 2013, and his PhD in Physics in 2017 University of Naples “Federico II” (Italy). Actually, he has a post-doc grant funded by the Italian Institute of Nuclear Physics. His research work is related to the development and evaluation of innovative x-ray based imaging technologies. In particular, he has large expertise in medical images evaluation and elaboration, with particular focus on technologies for 2D and 3D breast imaging. Lately, his research work mainly focused on the in-silico reproduction of x-ray breast imaging technologies for their evaluation and development with reduced costs and patient risks.

L. Cristofolini

Luca Cristofolini is a Full  Professor of Biomechanics at the University of Bologna since 2012. Formerly he was an Associate Professor of Biomechanics,  and Research Assistant in Experimental Mechanics. Luca earned his PhD in Biomedical Engineering in 1996,  and his Master in Mechanical Engineering cum laude in 1992.  His research field covers experimental stress analysis and in vitro biomechanical simulations. His research focuses on orthopaedic biomechanics, topics: (1) design and validation of implantable devices (trauma, joint replacement, and spine); and (2) multiscale mechanical testing of bone structures.  While his expertise is on experimental mechanics,  his work is strongly integrated with finite element (FE) modelling (identification of model parameters, experimental validation, exploitation of models to optimize in vitro experiments).  He is in the Editorial Board of J. Biomechanics, of Medical Engineering & Physics and of Strain. He served in the Council of the ESB from 2012 to 2020.  He published over 200 journal papers,  500+ conference papers and 3 patents (Google Scholar: 10681 Citations, h-index=46).

P. Bifulco

Paolo Bifulco received the M.Sc. degree in Electronics Engineering, in 1993, and the Ph.D. degree in Bioengineering, in 1998. Currently, he is currently Associate Professor with the Dept. of Electrical Engineering and Information Technology at the University “Federico II” of Naples, Italy. He teaches Biomedical  Instrumentation and Clinical Engineering topics. His research activity is mainly in the fields of biomedical signal and image processing, medical devices and clinical engineering. He is author of more than 80 peer-reviewed articles on international journals and more than 140 conference papers.