Research article

Relationship of compartment-specific structural knee status at baseline with change in cartilage morphology: a prospective observational study using data from the osteoarthritis initiative

Felix Eckstein^1,2 , Wolfgang Wirth^1,2 , Martin I Hudelmaier^1,2 , Susanne Maschek^1,2 , Wolfgang Hitzl³ , Bradley T Wyman⁴ , Michael Nevitt⁵ , Marie-Pierre Hellio Le Graverand⁵ , David Hunter⁶ and the OA Initiative Investigator Group

¹  Institute of Anatomy and Musculoskeletal Research, Paracelsus Medical University, Strubergasse 21, A5020 Salzburg, Austria

²  Chondrometrics GmbH, Ulrichshöglerstrasse 23, D83404 Ainring, Germany

³  Research Office, Paracelsus Medical University, Strubergasse 21, A 5020 Salzburg, Austria

⁴  Pfizer Global Research and Development, 50 Pequot Ave, New London, CT 06320, USA

⁵  University of California and OA Initiative Coordinating Center, 185 Berry Street, San Francisco, CA 94107, USA

⁶  Division of Research, New England Baptist Hospital, 125 Parker Hill Avenue, Boston, MA 02120, USA

author email corresponding author email

Arthritis Research & Therapy 2009, 11:R90doi:10.1186/ar2732

Published:	17 June 2009

Abstract

Introduction

The aim was to investigate the relationship of cartilage loss (change in medial femorotibial cartilage thickness measured with magnetic resonance imaging (MRI)) with compartment-specific baseline radiographic findings and MRI cartilage morphometry features, and to identify which baseline features can be used for stratification of fast progressors.

Methods

An age and gender stratified subsample of the osteoarthritis (OA) initiative progression subcohort (79 women; 77 men; age 60.9 ± 9.9 years; body mass index (BMI) 30.3 ± 4.7) with symptomatic, radiographic OA in at least one knee was studied. Baseline fixed flexion radiographs were read centrally and adjudicated, and cartilage morphometry was performed at baseline and at one year follow-up from coronal FLASH 3 Tesla MR images of the right knee.

Results

Osteophyte status at baseline was not associated with medial cartilage loss. Knees with medial joint space narrowing tended to show higher rates of change than those without, but the relationship was not statistically significant. Knees with medial femoral subchondral bone sclerosis (radiography), medial denuded subchondral bone areas (MRI), and low cartilage thickness (MRI) at baseline displayed significantly higher cartilage loss than those without, both with and without adjusting for age, sex, and BMI. Participants with denuded subchondral bone showed a standardized response mean of up to -0.64 versus -0.33 for the entire subcohort.

Conclusions

The results indicate that radiographic and MRI cartilage morphometry features suggestive of advanced disease appear to be associated with greater cartilage loss. These features may be suited for selecting patients with a higher likelihood of fast progression in studies that attempt to demonstrate the cartilage-preserving effect of disease-modifying osteoarthritis drugs.