Oxford consensus on primary cam morphology and femoroacetabular impingement syndrome: part 1-definitions, terminology, taxonomy and imaging outcomes

H Paul Dijkstra; Sean Mc Auliffe; Clare L Ardern; Joanne L Kemp; Andrea Britt Mosler; Amy Price; Paul Blazey; Dawn Richards; Abdulaziz Farooq; Andreas Serner; Eugene McNally; Vasco Mascarenhas; Richard W Willy; Jason L Oke; Karim M Khan; Sion Glyn-Jones; Mike Clarke; Trisha Greenhalgh; Young Athlete’s Hip Research (YAHiR) Collaborative

doi:10.1136/bjsports-2022-106085

Oxford consensus on primary cam morphology and femoroacetabular impingement syndrome: part 1-definitions, terminology, taxonomy and imaging outcomes

Br J Sports Med. 2022 Dec 6;57(6):325-341. doi: 10.1136/bjsports-2022-106085. Online ahead of print.

Authors

H Paul Dijkstra^{1

2}, Sean Mc Auliffe^{3

4}, Clare L Ardern^{5

6}, Joanne L Kemp⁶, Andrea Britt Mosler⁶, Amy Price⁷, Paul Blazey⁸, Dawn Richards⁹, Abdulaziz Farooq¹⁰, Andreas Serner¹¹, Eugene McNally¹², Vasco Mascarenhas¹³, Richard W Willy¹⁴, Jason L Oke¹⁵, Karim M Khan¹⁶, Sion Glyn-Jones¹⁷, Mike Clarke¹⁸, Trisha Greenhalgh¹⁵; Young Athlete’s Hip Research (YAHiR) Collaborative

Collaborators

Young Athlete’s Hip Research (YAHiR) Collaborative:
Rintje Agricola, Thor Einar Andersen, Olufemi Ayeni, Ian Beasley, Mario Bizzini, Marco Cardinale, Tafadzwa Chiokwindo, Richard de Villiers, Lars Engebretsen, Tom Entwisle, Emin Ergen, Scott Fernquest, Celeste Geertsema, Mo Gimpel, Fares Haddad, David Hanff, Joshua Heerey, Per Holmich, Franco Milko Impellizzeri, Julie Sandell Jacobsen, Christa Janse van Rensburg, Ara Kassarjian, Vikas Khanduja, Stephanie Kliethermes, Cara Lewis, Travis Maak, Susan Mayes, Inger Mechlenburg, Nonhlanhla Mkumbuzi, Sofie Nelis, Antony Palmer, Theodora Papadopoulou, Marc Philippon, Lauren Pierpoint, Lindsey Plass, Noel Pollock, Michael Reiman, Nia Roberts, Nikki Rommers, Nisrine Sawaya, Toni-Jane Snoxell, Jomar Souza, Louise Strickland, Tina Taseska, Kristian Thorborg, Jane Thornton, Johannes Tol, Larissa Trease, Pim van Klij, Pieter Volcke, Adam Weir, Fiona Wilson, Mara Yamauchi

Affiliations

¹ Department of Medical Education, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar Paul.Dijkstra@aspetar.com.
² Department for Continuing Education, University of Oxford, Oxford, UK.
³ Department of Physical Therapy & Rehabilitation Science, Qatar University, Doha, Qatar.
⁴ Department of Physiotherapy, School of Medicine, Trinity College Dublin, Dublin, Ireland.
⁵ Department of Family Practice, The University of British Columbia, Vancouver, British Columbia, Canada.
⁶ La Trobe Sport and Exercise Medicine Research Centre; Australian IOC Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Victoria, Australia.
⁷ Department of Anesthesia, Informatics and Media Lab, Stanford University School of Medicine, Stanford, California, USA.
⁸ Center for Hip Health and Mobility, The University of British Columbia, Vancouver, British Columbia, Canada.
⁹ Five02 Labs Inc, Toronto, Ontario, Canada.
¹⁰ FIFA Medical Centre of Excellence, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
¹¹ FIFA Medical, Federation Internationale de Football Association, Zurich, Switzerland.
¹² Oxford Musculoskeletal Radiology, Oxford, UK.
¹³ Advanced Imaging Research Consortium UIME, Hospital da Luz, Lisboa, Portugal.
¹⁴ Physical Therapy and Movement Science, University of Montana, Missoula, Montana, USA.
¹⁵ Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
¹⁶ Family Practice & Kinesiology, The University of British Columbia, Vancouver, British Columbia, Canada.
¹⁷ Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
¹⁸ Northern Ireland Methodology Hub, Queen's University Belfast, Belfast, UK.

Abstract

Introduction: Primary cam morphology is a mostly benign bony prominence that develops at the femoral head-neck junction of the hip, but it is highly prevalent in many athlete populations. In the small proportion of athletes for whom it is not benign, the resulting hip osteoarthritis can be debilitating. Clinicians, athletes, patients and researchers do not yet agree on important primary cam morphology elements. We aimed to ascertain and improve the level of agreement on primary cam morphology definitions, terminology, taxonomy and imaging outcome measures.

Methods: To collect and aggregate informed opinions, an expert panel-the Young Athlete's Hip Research Collaborative-rated primary cam morphology definition, terminology, taxonomy and imaging outcome statements through an online Delphi exercise followed by an online meeting to explore areas of tension and dissent. Reporting followed Conducting and REporting DElphi Studies.

Results: A diverse and inclusive Delphi panel (n=65 for rounds 1 and 2, representing 18 countries; 6 stakeholder groups; 40% women) agreed on 35 of 47 statements in 4 domains, while surfacing areas of tension and dissent. This Delphi panel agreed on four key issues essential to moving research and clinical care forward around primary cam morphology. They agreed on: (1) definition, confirming its conceptual attributes (tissue type, size, location, shape and ownership); (2) terminology-use 'morphology' and not terms with a negative connotation like 'lesion', 'abnormality' or 'deformity'; (3) taxonomy, distinguishing between primary and secondary cam morphology, and (4) imaging outcomes, a continuous bone/cartilage alpha angle on radial femoral head-neck MRI for primary cam morphology aetiology research.

Conclusion: This consensus provides athletes, patients, clinicians and researchers with a strong foundation to guide more precise communication, better clinical decision-making and higher value research about primary cam morphology and its natural history.

Keywords: Athletes; Consensus; Hip; Osteoarthritis; Sports medicine.