Searching for subgroups of patients benefitting most from meniscal surgery – do they exist? PhD thesis Kenneth Pihl 2019 Research Unit for Musculoskeletal Function and Physiotherapy Department of Sports Science and Clinical Biomechanics Faculty of Health Sciences University of Southern Denmark Colophon PhD thesis: August 1, 2019 PhD defence: October 23, 2019 The PhD project was funded by the Independent Research Fund Denmark | Medical Sciences, and the Region of Southern Denmark. PhD supervisor Professor Jonas B. Thorlund, PhD University of Southern Denmark, Denmark Committee members Professor Ian Harris, MD, PhD University of New South Wales, Australia Professor Alma B. Pedersen, MD, PhD, Dr.Med. Aarhus University, Denmark Chairman: Professor Alice Kongsted, PhD University of Southern Denmark, Denmark Table of contents Preface ........................................................................................................................ 6 List of papers ............................................................................................................... 7 Thesis at a glance ....................................................................................................... 8 Description of contributions ......................................................................................... 9 List of tables and figures ............................................................................................ 10 Abbreviations ............................................................................................................. 11 Introduction ................................................................................................................ 12 Scope of the problem ......................................................................................................... 12 The menisci ........................................................................................................................ 13 Meniscus tears ................................................................................................................... 14 Indications for meniscal surgery ........................................................................................ 15 Mechanical symptoms ....................................................................................................... 15 Identifying patients improving most .................................................................................... 17 Aims of the thesis ...................................................................................................... 18 Specific aims ...................................................................................................................... 18 Methods ..................................................................................................................... 19 Study designs .................................................................................................................... 19 Data source and participants ............................................................................................. 19 Descriptive variables .......................................................................................................... 21 Outcomes ........................................................................................................................... 23 Surgery data ...................................................................................................................... 24 Statistics (paper I-III) .......................................................................................................... 24 Statistics paper IV .............................................................................................................. 26 Results ....................................................................................................................... 29 Mechanical symptoms ....................................................................................................... 29 Prognostic models ............................................................................................................. 32 Discussion ................................................................................................................. 34 Main findings ...................................................................................................................... 34 Mechanical symptoms – features of meniscal tears? ........................................................ 34 Subgroups of patients benefitting from APM – do they exist? ........................................... 36 Limitations .......................................................................................................................... 39 Clinical and research implications ...................................................................................... 40 Conclusion ................................................................................................................. 42 Summary ................................................................................................................... 43 4 Dansk resumé (Danish summary) ............................................................................. 44 Acknowledgements ................................................................................................... 45 References ................................................................................................................ 47 Appendices ................................................................................................................ 54 Paper I ............................................................................................................................... 55 Paper II .............................................................................................................................. 56 Paper III ............................................................................................................................. 57 Paper IV ............................................................................................................................. 58 5 Preface This thesis was completed at the Research Unit for Musculoskeletal Function and Physiotherapy at Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark. The sole supervisor was Associate Professor Jonas B. Thorlund (University of Southern Denmark). The thesis includes data on 641 patients who had a verified meniscal tear at knee arthroscopy and 176 patients who had knee arthroscopy on suspicion of a meniscal tear but where no meniscal tear was identified. Patients had surgery at either Odense University Hospital (Odense or Svendborg) or Lillebaelt Hospital (Kolding or Vejle) in the Region of Southern Denmark between February 1, 2013 and January 31, 2015. The single studies that the thesis comprises were conducted in collaboration with the Research Institute for Primary Care & Health Sciences, Keele University, Keele, United Kingdom, the Clinical Epidemiology Unit, Lund University, Lund, Sweden, Department of Orthopaedics and Traumatology, Odense University Hospital, Odense, Denmark, and Department of Orthopaedics, Lillebaelt Hospital, Kolding and Vejle, Denmark. The PhD project was funded by the Independent Research Fund Denmark | Medical Sciences, and the Region of Southern Denmark. 6 List of papers This thesis is comprised of the following four papers. The papers will be referred to by their roman numerals throughout the thesis. I. Pihl K, Turkiewicz A, Englund M, Lohmander LS, Jorgensen U, Nissen N, Schjerning J, Thorlund JB. Association of specific meniscal pathologies and other structural pathologies with self-reported mechanical symptoms: A cross- sectional study of 566 patients undergoing meniscal surgery. J Sci Med Sport 2019;22:151-57. II. Thorlund JB, Pihl K, Nissen N, Jorgensen U, Fristed JV, Lohmander LS, Englund M. Conundrum of mechanical knee symptoms: signifying feature of a meniscal tear? Br J Sports Med 2019;53:299-303. III. Pihl K, Turkiewicz A, Englund M, Lohmander LS, Jorgensen U, Nissen N, Schjerning J, Thorlund JB. Change in patient-reported outcomes in patients with and without mechanical symptoms undergoing arthroscopic meniscal surgery: A prospective cohort study. Osteoarthritis Cartilage 2018;26:1008-16. IV. Pihl K, Ensor J, Peat G, Englund M, Lohmander LS, Jorgensen U, Nissen N, Fristed JV, Thorlund JB. Wild-goose chase, no predictable patient subgroups who benefit from meniscal surgery: patient-reported outcomes of 641 patients 1 year after surgery. Br J Sports Med Epub ahead of print: 2019 Jun 11. 7 Thesis at a glance Paper I & II III IV Aim To investigate if specific To compare change in To develop a meniscal pathology (i.e. patient-reported prognostic model for tear type, location, etc.) outcomes from before predicting patients’ and other concurrent to 52 weeks after change in self- structural pathologies [I] arthroscopic meniscal reported outcomes and having a meniscal surgery between from before to 52 tear [II] are associated patients with and weeks after with self-reported without preoperative arthroscopic meniscal preoperative mechanical mechanical surgery. symptoms. symptoms. Design Cross-sectional studies. Prospective cohort Prognostic model study. study using cohort data. Participants 566 patients having 150 patients aged £40 641 patients having meniscal surgery [I]. years and 491 meniscal surgery.