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Ann Rheum Dis 72:707-714 doi:10.1136/annrheumdis-2011-201164
  • Clinical and epidemiological research
  • Extended report

Quantitative MRI measures of cartilage predict knee replacement: a case–control study from the Osteoarthritis Initiative

  1. for the OAI investigators
  1. 1Institute of Anatomy, Paracelsus Medical University, Salzburg, Austria
  2. 2Chondrometrics GmbH, Ainring, Germany
  3. 3Division of Rheumatology and Clinical Immunology, University of Pittsburgh and Pittsburgh VAHS, Pittsburgh, Pennsylvania, USA
  4. 4Department of Epidemiology, Grad. Sch. of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
  5. 5Department of Radiology, Boston University School of Medicine and Boston Imaging Core Lab (BICL), LLC, Boston, Massachusetts, USA
  6. 6Department of Epidemiology and Biostatistics, OAI Coordinating Ctr., University of California, San Francisco (UCSF), San Francisco, California, USA
  7. 7Novartis Pharma AG, Basel, Swizerland
  8. 8Department of Rheumatology, Royal North Shore Hospital and Northern Clinical School, University Sydney, Sydney, New South Wales, Australia
  1. Correspondence to Professor Felix Eckstein, Institute of Anatomy and Musculoskeletal Research, PMU, Strubergasse 21, Salzburg A5020, Austria; felix.eckstein{at}pmu.ac.at
  • Received 9 December 2011
  • Accepted 19 May 2012
  • Published Online First 23 June 2012

Abstract

Objective Knee osteoarthritis commonly requires joint replacement, substantially reduces quality of life and increases healthcare utilisation and costs. This study aimed to identify whether quantitative measures of articular cartilage structure predict knee replacement, and to establish their utility as outcomes in clinical trials of disease-modifying therapy.

Methods A nested case–control study was performed in Osteoarthritis Initiative participants, a multicentre observational cohort of 4796 participants with or at risk of knee osteoarthritis. 127 knees were replaced between baseline and 4 years follow-up, and one control knee per case matched for baseline radiographic disease stage (Kellgren–Lawrence grade; KLG), gender and age. Quantitative cartilage measures were obtained from 3 T magnetic resonance images at the exam before knee replacement, and longitudinal change during the previous 12 months when available (n=110).

Results Cartilage thickness loss in the central and total medial femorotibial compartment (primary and secondary predictor variables) was significantly greater in case than control knees (AUC=0.59/0.58). Differences in cartilage loss were greater at earlier than later radiographic disease stages (p<0.01 for interaction with KLG). Cartilage thickness loss in the central tibia was the most predictive longitudinal measure (AUC=0.64). Denuded bone areas in the medial femur were the most predictive and discriminatory cross-sectional measure between case and control knees (AUC=0.66).

Conclusions This study demonstrates the predictive value of quantitative, MRI-based measures of cartilage for the clinically relevant endpoint of knee replacement, providing support for their utility in clinical trials to evaluate the effectiveness of structure-modifying intervention.