title: Physical Activity Is Related with Cartilage Quality in Women with Knee Osteoarthritis.
abstract: To study the relationship between 12-month leisure-time physical activity (LTPA) level and changes in estimated biochemical composition of tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis (OA).
  
  
  
  Originally, 87 volunteer postmenopausal women, age 60 to 68 yr, with mild knee OA (Kellgren Lawrence I/II and knee pain) participated in a randomized controlled, 4-month aquatic training trial (RCT), after which 76 completed the 12-month postintervention follow-up period. Self-reported LTPA was collected along the 12-month period using a diary from which MET task hours per month were calculated. Participants were divided into MET task hour tertiles: 1, lowest (n = 25); 2 = middle (n = 25) and 3 = highest (n = 26). The biochemical composition of the cartilage was estimated using transverse relaxation time (T2) mapping sensitive to the properties of the collagen network and delayed gadolinium-enhanced magnetic resonance imaging of the cartilage (dGEMRIC index) sensitive to the cartilage glycosaminoglycan content. Secondary outcomes were cardiorespiratory fitness, isometric knee extension and flexion force, and the knee injury and OA outcome questionnaire.
  
  
  
  During the 12-month follow-up period, there was a significant linear relationship between higher LTPA level and increased dGEMRIC index changes in the posterior region of interest (ROI) of the lateral (P = 0.003 for linearity) and medial (P = 0.006) femoral cartilage. Furthermore, these changes were seen in the posterior lateral femoral cartilage superficial (P = 0.004) and deep (P = 0.007) ROI and in the posterior medial superficial ROI (P < 0.001). There was no linear relationship between LTPA level and other measured variables.
  
  
  
  These results suggest that higher LTPA level is related to regional increases in estimated glycosaminoglycan content of tibiofemoral cartilage in postmenopausal women with mild knee OA as measured with dGEMRIC index during a 12-month period.
authors.affiliation: 1Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, FINLAND; 2Department of Physical Medicine and Rehabilitation, Central Finland Central Hospital, Jyväskylä, FINLAND; 3Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, FINLAND; 4Department of Diagnostic Radiology, Oulu University Hospital, Oulu, FINLAND; 5Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, FINLAND; 6Department of Surgery, Central Finland Central Hospital, Jyväskylä, FINLAND; 7Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, FINLAND; 8Unit of Primary Health Care, Kuopio University Hospital, Kuopio, FINLAND; and 9Department of Orthopaedics and Traumatology, University of Helsinki, and Helsinki University Hospital, Helsinki, FINLAND.
authors.forename: Matti
authors.initials: M
authors.lastname: Munukka
authors.forename: Benjamin
authors.initials: B
authors.lastname: Waller
authors.forename: Arja
authors.initials: A
authors.lastname: Häkkinen
authors.forename: Miika T
authors.initials: MT
authors.lastname: Nieminen
authors.forename: Eveliina
authors.initials: E
authors.lastname: Lammentausta
authors.forename: Urho M
authors.initials: UM
authors.lastname: Kujala
authors.forename: Juha
authors.initials: J
authors.lastname: Paloneva
authors.forename: Hannu
authors.initials: H
authors.lastname: Kautiainen
authors.forename: Ilkka
authors.initials: I
authors.lastname: Kiviranta
authors.forename: Ari
authors.initials: A
authors.lastname: Heinonen
mesh_terms: D000072599:Cardiorespiratory Fitness / Q000502:physiology; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D015444:Exercise / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006025:Glycosaminoglycans / Q000378:metabolism*; D006801:Humans; D007719:Knee Joint / Q000378:metabolism* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000378:metabolism* / Q000473:pathology; D012647:Self-Assessment
chemical_list: D006025:Glycosaminoglycans