title: Pre-Osteoarthritis: Definition and Diagnosis of an Elusive Clinical Entity.
abstract: OBJECTIVE
  An attempt to define pre-osteoarthritis (OA) versus early OA and definitive osteoarthritis.
  
  
  METHODS
  A group of specialists in the field of cartilage science and treatment was formed to consider the nature of OA onset and its possible diagnosis.
  
  
  RESULTS
  Late-stage OA, necessitating total joint replacement, is the end stage of a biological process, with many previous earlier stages. Early-stage OA has been defined and involves structural changes identified by arthroscopy or radiography. The group argued that before the "early-stage OA" there must exist a stage where cellular processes, due to the presence of risk factors, have kicked into action but have not yet resulted in structural changes. The group suggested that this stage could be called "pre-osteoarthritis" (pre-OA).
  
  
  CONCLUSIONS
  The group suggests that defining points of initiation for OA in the knee could be defined, for example, by traumatic episodes or surgical meniscectomy. Such events may set in motion metabolic processes that could be diagnosed by modern MRI protocols or arthroscopy including probing techniques before structural changes of early OA have developed. Preventive measures should preferably be applied at this pre-OA stage in order to stop the projected OA "epidemic."
authors.affiliation: Medical Management Centre, LIME, Karolinska Institute, Stockholm, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Ryd
authors.affiliation: Cartilage Research Unit, University of Gothenburg. Department of Orthopaedics, Kungsbacka Hospital, Kungsbacka, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Brittberg
authors.affiliation: Department of Orthopedics, Southern Hospital, Stockholm, Sweden.
authors.forename: Karl
authors.initials: K
authors.lastname: Eriksson
authors.affiliation: Faculty of Science and Forestry, University of Eastern Finland, Kuopio, Finland.
authors.forename: Jukka S
authors.initials: JS
authors.lastname: Jurvelin
authors.affiliation: Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Lindahl
authors.affiliation: Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Marlovits
authors.affiliation: Episurf Medical, Stockholm, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Möller
authors.affiliation: Keele University, RJAH, Oswestry, UK.
authors.forename: James B
authors.initials: JB
authors.lastname: Richardson
authors.affiliation: Sport Clinic Zürich, Klinik Hirslanden, Zürich, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Steinwachs
authors.affiliation: Cartilage Engineering + Regeneration Laboratory, Zürich, Switzerland.
authors.forename: Marcy
authors.initials: M
authors.lastname: Zenobi-Wong
keywords: diagnosis; diagnostics; epidemiology; general; posttraumatic arthritis