title: Organisation of the motor cortex differs between people with and without knee osteoarthritis.
abstract: BACKGROUND
  The aim of this study was to investigate possible differences in the organisation of the motor cortex in people with knee osteoarthritis (OA) and whether there is an association between cortical organisation and accuracy of a motor task.
  
  
  METHODS
  fMRI data were collected while 11 participants with moderate/severe right knee OA (6 male, 69 ± 6 (mean ± SD) years) and seven asymptomatic controls (5 male, 64 ± 6 years) performed three visually guided, variable force, force matching motor tasks involving isolated isometric muscle contractions of: 1) quadriceps (knee), 2) tibialis anterior (ankle) and, 3) finger/thumb flexor (hand) muscles. fMRI data were used to map the loci of peak activation in the motor cortex during the three tasks and to assess whether there were differences in the organisation of the motor cortex between the groups for the three motor tasks. Root mean square of the difference between target and generated forces during muscle contraction quantified task accuracy.
  
  
  RESULTS
  A 4.1 mm anterior shift in the representation of the knee (p = 0.03) and swap of the relative position of the knee and ankle representations in the motor cortex (p = 0.003) were found in people with knee OA. Poorer performance of the knee task was associated with more anterior placement of motor cortex loci in people with (p = 0.05) and without (p = 0.02) knee OA.
  
  
  CONCLUSIONS
  Differences in the organisation of the motor cortex in knee OA was demonstrated in relation to performance of knee and ankle motor tasks and was related to quality of performance of the knee motor task. These results highlight the possible mechanistic link between cortical changes and modified motor behavior in people with knee OA.
authors.affiliation: Department of Physiotherapy, The University of Melbourne, Melbourne, Australia. c.shanahan@student.unimelb.edu.au.|The Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, 30 Royal Parade, Parkville, VIC, 3052, Australia. c.shanahan@student.unimelb.edu.au.
authors.forename: Camille J
authors.initials: CJ
authors.lastname: Shanahan
authors.affiliation: Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, The University of Queensland, Brisbane, Australia. p.hodges@uq.edu.au.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Hodges
authors.affiliation: Department of Physiotherapy, The University of Melbourne, Melbourne, Australia. timw@unimelb.edu.au.
authors.forename: Tim V
authors.initials: TV
authors.lastname: Wrigley
authors.affiliation: Department of Physiotherapy, The University of Melbourne, Melbourne, Australia. k.bennell@unimelb.edu.au.
authors.forename: Kim L
authors.initials: KL
authors.lastname: Bennell
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, 30 Royal Parade, Parkville, VIC, 3052, Australia. michael.j.farrell@monash.edu.|Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Australia. michael.j.farrell@monash.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Farrell
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000378:metabolism* / Q000473:pathology*; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000378:metabolism*; D011597:Psychomotor Performance / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology