A consensus-based classification of minor complications, major complications, and failure after anterior cruciate ligament reconstruction: A modified delphi study

INTRODUCTION: The aim of this study was to establish a consensus-based classification of postoperative events following anterior cruciate ligament reconstruction (ACLR), clearly distinguishing no complication/normal clinical course, minor complication, major complication, and failure, using a structured Delphi methodology among international experts in anterior cruciate ligament (ACL) surgery. METHODS: A three-round modified Delphi process was conducted involving international high-volume ACL surgeons. An initial set of statements addressing potential postoperative events after ACLR was developed by a working group based on clinical expertise and contemporary literature. Panelists classified each statement as no complication/normal clinical course, minor complication, major complication, or failure. Consensus was predefined as ≥75% agreement within a single category. Statements reaching consensus were retained, whereas non-consensus statements were revised and re-evaluated in subsequent rounds. RESULTS: Thirty-nine experts completed the first and second Delphi rounds, and 30 (76.9%) completed the third round. The initial 52 statements were expanded to 67 in round two and refined to 46 in round three. Consensus was achieved for 14 statements (26.9%) in round one, 21 statements (31.3%) in round two, and 20 statements (43.5%) in round three. Overall, consensus was reached for 55 statements, forming the final classification framework. The panel clearly distinguished graft failure-defined as graft insufficiency or symptomatic instability-from major complications requiring surgical intervention or associated with substantial morbidity, and from minor complications or expected postoperative findings. Notably, traumatic graft rupture following a clearly documented new injury was not considered a postoperative complication. CONCLUSIONS: This international Delphi consensus establishes a standardized and clinically meaningful classification of postoperative events following ACLR. By clearly distinguishing no complication, minor complication, major complication, and failure, this framework provides a shared language that may improve consistency in outcome reporting, facilitate comparison across studies, and enhance the interpretability of clinical research and registry data. LEVEL OF EVIDENCE: V, expert consensus.

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Journal
Journal of ISAKOS Joint Disorders & Orthopaedic Sports Medicine
Published
2026-03-31
DOI
https://doi.org/10.1016/j.jisako.2026.101104
Primary Topic
Knee injuries and reconstruction techniques
Type
article
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article

A consensus-based classification of minor complications, major complications, and failure after anterior cruciate ligament reconstruction: A modified delphi study

Adrian Deichsel, Erik Hohmann, Thomas Rudolf Pfeiffer, Rainer Siebold et al.
Journal of ISAKOS Joint Disorders & Orthopaedic Sports Medicine
Knee injuries and reconstruction techniques
article

A consensus-based classification of minor complications, major complications, and failure after anterior cruciate ligament reconstruction: A modified delphi study

Adrian Deichsel, Erik Hohmann, Thomas Rudolf Pfeiffer, Rainer Siebold, Natalie Mengis, Jakob Ackermann, Thore Zantop, Ralph Akoto, Christian Lattermann, Arasch Wafaisade, Dominic T. Mathis, Andrea Achtnich, Florian Dirisamer, Gergő Merkely, Andreas B. Imhoff, Johannes Zellner, David Henri Dejour, Julian Mehl, Matthias J. Feucht, Lukas Willinger, Georg Brandl, Daniel Guenther, Elisabeth Abermann, Christian Schoepp, Lena Eggeling, James H. Lubowitz, Christoph Kittl, Larissa Eckl, Sven Scheffler, Maiti Münchgesang, Martin Volz, Anton Ferdinand Schmidt, Andy Williams, Stefan Nehrer, Christian Fink, Riccardo D’Ambrosi, Peter Angele, Karl-Friederich Schüttler, Volker Mushal, Roland Becker, Tobias Jung, Elmar Herbst, Brenda Laky, Lukas Nawid Münch, Peter Philipp Koch, Björn H. Drews, Matthias Krause, Christian Egloff
article en

Abstract

INTRODUCTION: The aim of this study was to establish a consensus-based classification of postoperative events following anterior cruciate ligament reconstruction (ACLR), clearly distinguishing no complication/normal clinical course, minor complication, major complication, and failure, using a structured Delphi methodology among international experts in anterior cruciate ligament (ACL) surgery. METHODS: A three-round modified Delphi process was conducted involving international high-volume ACL surgeons. An initial set of statements addressing potential postoperative events after ACLR was developed by a working group based on clinical expertise and contemporary literature. Panelists classified each statement as no complication/normal clinical course, minor complication, major complication, or failure. Consensus was predefined as ≥75% agreement within a single category. Statements reaching consensus were retained, whereas non-consensus statements were revised and re-evaluated in subsequent rounds. RESULTS: Thirty-nine experts completed the first and second Delphi rounds, and 30 (76.9%) completed the third round. The initial 52 statements were expanded to 67 in round two and refined to 46 in round three. Consensus was achieved for 14 statements (26.9%) in round one, 21 statements (31.3%) in round two, and 20 statements (43.5%) in round three. Overall, consensus was reached for 55 statements, forming the final classification framework. The panel clearly distinguished graft failure-defined as graft insufficiency or symptomatic instability-from major complications requiring surgical intervention or associated with substantial morbidity, and from minor complications or expected postoperative findings. Notably, traumatic graft rupture following a clearly documented new injury was not considered a postoperative complication. CONCLUSIONS: This international Delphi consensus establishes a standardized and clinically meaningful classification of postoperative events following ACLR. By clearly distinguishing no complication, minor complication, major complication, and failure, this framework provides a shared language that may improve consistency in outcome reporting, facilitate comparison across studies, and enhance the interpretability of clinical research and registry data. LEVEL OF EVIDENCE: V, expert consensus.

Journal of ISAKOS Joint Disorders & Orthopaedic Sports MedicineVol. 18
Semmelweis University (HU), OTH Regensburg (DE), Universität für Weiterbildung Krems (AT), Institute of Contemporary Art (US), Winterthur Museum Garden and Library (US), Harvard University (US), Witten/Herdecke University (DE), Universität Hamburg (DE), University of Freiburg (DE), Atos (France) (FR), University of Basel (CH), Freddie Mac (United States) (US), TUM Klinikum (DE), Tumaini University (TZ), MicroPort Orthopedics (Netherlands) (NL), European Neuroendocrine Tumor Society (DE), Massachusetts General Hospital (US), Sana Klinikum Lichtenberg (DE), Communauté urbaine de Lyon (FR), Ravensburg University of Cooperative Education (DE), UPMC Health System (US), Istituto Clinico Sant'Ambrogio (IT), Raumedic (Germany) (DE), University Hospital Münster (DE), University Medical Center Hamburg-Eppendorf (DE), Schulthess-Klinik (CH), Universitätsklinik Balgrist (CH), St. Vinzenz Kliniken Pfronten im Allgäu (DE), Kliniken der Stadt Köln (DE), Lungenklinik Köln-Merheim (DE), Diakonissenkrankenhaus (DE), BG Klinikum Duisburg (DE), Medizinische Hochschule Brandenburg Theodor Fontane (DE), Kantonsspital Baselland Standort Bruderholz (CH), Universitätszahnklinik Wien (AT), Fortius Clinic (GB), Universitätsklinikum Brandenburg an der Havel (DE), Gelenkpunkt (AT), Allergiezentrum Wien West (AT), BG Klinikum Hamburg (DE), Technical University of Munich (DE), University of Pretoria (ZA), Medical University of Vienna (AT), Charité - Universitätsmedizin Berlin (DE)
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