title: Functional ankle instability as a risk factor for osteoarthritis: using T2-mapping to analyze early cartilage degeneration in the ankle joint of young athletes.
abstract: OBJECTIVE
  The aim of this study was to investigate, using T2-mapping, the impact of functional instability in the ankle joint on the development of early cartilage damage.
  
  
  METHODS
  Ethical approval for this study was provided. Thirty-six volunteers from the university sports program were divided into three groups according to their ankle status: functional ankle instability (FAI, initial ankle sprain with residual instability); ankle sprain Copers (initial sprain, without residual instability); and controls (without a history of ankle injuries). Quantitative T2-mapping magnetic resonance imaging (MRI) was performed at the beginning ('early-unloading') and at the end ('late-unloading') of the MR-examination, with a mean time span of 27 min. Zonal region-of-interest T2-mapping was performed on the talar and tibial cartilage in the deep and superficial layers. The inter-group comparisons of T2-values were analyzed using paired and unpaired t-tests. Statistical analysis of variance was performed.
  
  
  RESULTS
  T2-values showed significant to highly significant differences in 11 of 12 regions throughout the groups. In early-unloading, the FAI-group showed a significant increase in quantitative T2-values in the medial, talar regions (P = 0.008, P = 0.027), whereas the Coper-group showed this enhancement in the central-lateral regions (P = 0.05). Especially the comparison of early-loading to late-unloading values revealed significantly decreasing T2-values over time laterally and significantly increasing T2-values medially in the FAI-group, which were not present in the Coper- or control-group.
  
  
  CONCLUSIONS
  Functional instability causes unbalanced loading in the ankle joint, resulting in cartilage alterations as assessed by quantitative T2-mapping. This approach can visualize and localize early cartilage abnormalities, possibly enabling specific treatment options to prevent osteoarthritis in young athletes.
authors.affiliation: Department of Trauma Surgery, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Golditz
authors.affiliation: Institute of Sport Science and Sport, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Steib
authors.affiliation: Institute of Sport Science and Sport, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Pfeifer
authors.affiliation: Department of Radiology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Uder
authors.affiliation: Department of Trauma Surgery, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Gelse
authors.affiliation: Department of Radiology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Janka
authors.affiliation: Department of Trauma Surgery, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: F F
authors.initials: FF
authors.lastname: Hennig
authors.affiliation: Department of Trauma Surgery, University of Erlangen-Nuremberg, Erlangen, Germany; MR Center of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria. Electronic address: goetz.welsch@uk-erlangen.de.
authors.forename: G H
authors.initials: GH
authors.lastname: Welsch
mesh_terms: D000328:Adult; D016512:Ankle Injuries / Q000473:pathology*; D000843:Ankle Joint / Q000473:pathology*; D056352:Athletes; D002357:Cartilage Diseases / Q000453:epidemiology / Q000473:pathology*; D002358:Cartilage, Articular / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007593:Joint Instability / Q000453:epidemiology / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010003:Osteoarthritis / Q000453:epidemiology / Q000473:pathology*; D012307:Risk Factors; D013180:Sprains and Strains / Q000453:epidemiology / Q000473:pathology; D055815:Young Adult
keywords: Functional ankle instability; Magnetic resonance imaging; Osteoarthritis; Sports medicine; T2-mapping