title: Knee Arthroscopy Cohort Southern Denmark (KACS): protocol for a prospective cohort study.
abstract: BACKGROUND
  Meniscus surgery is a high-volume surgery carried out on 1 million patients annually in the USA. The procedure is conducted on an outpatient basis and the patients leave the hospital a few hours after surgery. A critical oversight of previous studies is their failure to account for the type of meniscal tears. Meniscus tears can be categorised as traumatic or non-traumatic. Traumatic tears (TT) are usually observed in younger, more active individuals in an otherwise 'healthy' meniscus and joint. Non-traumatic tears (NTT) (ie, degenerative tears) are typically observed in the middle-aged (35-55 years) and older population but the aetiology is largely unclear. Knowledge about the potential difference of the effect of arthroscopic meniscus surgery on patient symptoms between patients with traumatic and NTT is sparse. Furthermore, little is known about the natural time course of patient perceived pain, function and quality of life after meniscus surgery and factors affecting these outcomes. The aim of this prospective cohort study is to investigate the natural time course of patient-reported outcomes in patients undergoing meniscus surgery, with particular emphasis on the role of type of symptom onset.
  
  
  METHODS
  This prospective cohort study enrol patients assigned for meniscus surgery. At the baseline (PRE surgery), patient characteristics are assessed using an email-based questionnaire also comprising several validated questionnaires assessing general health, knee-specific characteristics and patient's expectations of the surgery. Follow-up will be conducted at 12 and 52 weeks after meniscus surgery. The major outcomes will be differences in changes, from before to 52 weeks after surgery, in each of the five domains on the Knee injury and Osteoarthritis Outcome Score (KOOS) between patients undergoing surgery for traumatic compared with non-traumatic meniscus tears.
  
  
  RESULTS
  The study findings will be disseminated in peer-reviewed journals and presented at national and international conferences.
  
  
  BACKGROUND
  ClinicalTrials.gov Identifier: NCT01871272.
authors.affiliation: Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Jonas Bloch
authors.initials: JB
authors.lastname: Thorlund
authors.forename: Robin
authors.initials: R
authors.lastname: Christensen
authors.forename: Nis
authors.initials: N
authors.lastname: Nissen
authors.forename: Uffe
authors.initials: U
authors.lastname: Jørgensen
authors.forename: Jeppe
authors.initials: J
authors.lastname: Schjerning
authors.forename: Jens Christian
authors.initials: JC
authors.lastname: Pørneki
authors.forename: Martin
authors.initials: M
authors.lastname: Englund
authors.forename: L Stefan
authors.initials: LS
authors.lastname: Lohmander
keywords: Arthroscopy; Cohort study; Meniscus; Prospective study