title: Structural changes in the knee during weight loss maintenance after a significant weight loss in obese patients with osteoarthritis: a report of secondary outcome analyses from a randomized controlled trial.
abstract: OBJECTIVE
  To compare structural knee joint changes in obese patients with knee osteoarthritis (OA) that after an intensive weight loss therapy were randomized to continuous dietetic support, a specialized knee exercise program, or 'no attention' for 1 year.
  
  
  METHODS
  192 obese individuals with knee OA underwent an intensive 16-week weight loss program with subsequent randomization to one of the three treatment groups. Changes in cartilage loss, bone marrow lesions (BMLs), synovitis, and effusion were assessed using semi quantitative assessments of magnetic resonance imaging (MRI) obtained at weeks 0 and 68 applying the BLOKS score.
  
  
  RESULTS
  During the 52 weeks maintenance period the continuous dietary maintenance group support on average gained 1.1 kg (95% CI: -0.3:2.5) body mass, the exercise group gained 6.6 kg (95% CI 5.4:7.8) and the no-attention group gained 4.8 kg (95% CI: 2.9:6.7). There were no statistically significant between-group differences in changes in cartilage loss, synovitis or effusion at the follow-up (analysis of covariance; ANCOVA, P > 0.16), while there was an increased number of medial tibiofemoral BMLs in the exercise group (ANCOVA, P = 0.015) compared to both diet (difference: -0.21 [95%CI -0.40:-0.03]) and "no attention" (difference: -0.26 [95%CI -0.44:-0.07]) groups.
  
  
  CONCLUSIONS
  In this 1 year follow-up after weight-loss in obese knee OA patients, we found a potentially increased number of BMLs in the exercise group compared to the diet and no attention groups, with no between-group differences in changes in cartilage loss, synovitis or effusion. These findings should be interpreted with caution for exercise compliance, MRI methodology and follow-up time. (ClinicalTrials.gov identifier: NCT00655941).
authors.affiliation: The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals, Bispebjerg and Frederiksberg, DK-2000 Copenhagen F, Denmark. Electronic address: marius.henriksen@regionh.dk.
authors.forename: M
authors.initials: M
authors.lastname: Henriksen
authors.affiliation: The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals, Bispebjerg and Frederiksberg, DK-2000 Copenhagen F, Denmark; Institute of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, DK-5230 Odense, Denmark.
authors.forename: R
authors.initials: R
authors.lastname: Christensen
authors.affiliation: Kolling Institute, University of Sydney and Rheumatology Department, Royal North Shore Hospital, Sydney, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hunter
authors.affiliation: The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals, Bispebjerg and Frederiksberg, DK-2000 Copenhagen F, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Gudbergsen
authors.affiliation: The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals, Bispebjerg and Frederiksberg, DK-2000 Copenhagen F, Denmark; Department of Radiology, Copenhagen University Hospitals, Bispebjerg and Frederiksberg, DK-2000 Copenhagen F, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Boesen
authors.affiliation: Institute of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, DK-5230 Odense, Denmark; Department of Orthopedics, Clinical Sciences Lund, Lund University, Sweden.
authors.forename: L S
authors.initials: LS
authors.lastname: Lohmander
authors.affiliation: The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals, Bispebjerg and Frederiksberg, DK-2000 Copenhagen F, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Bliddal
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001853:Bone Marrow / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology; D004038:Diet, Reducing; D018450:Disease Progression; D005081:Exercise Therapy / Q000379:methods; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000628:therapy; D010003:Osteoarthritis / Q000209:etiology* / Q000473:pathology; D010349:Patient Compliance; D016896:Treatment Outcome; D015431:Weight Loss / Q000502:physiology*; D061217:Weight Reduction Programs / Q000379:methods*
keywords: Diet; Exercise; Magnetic resonance imaging; Weight loss; Weight loss maintenance