Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Change in Knee Cartilage Volume and Incident Meniscal Extrusion As Predictors of Change in Joint Space Width of the Tibiofemoral Joint: 5 Year Longitudinal Study.

Hall1,  Joanna, Laslett1,  Laura, Pelletier2,  Johanne M., Pelletier2,  Jean Pierre, Abram3,  François, Ding4,  Chang-Hai, Cicuttini5,  Flavia

University of Tasmania, Hobart, Australia
Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Notre-Dame Hospital, Montreal, QC
ArthroVision Inc., Montreal, QC
University of Tasmania & Monash University, Hobart, Australia
Monash University, Central and Eastern Clinical School, Melbourne, Australia

Background/Purpose:

Joint space width (JSW) on X-ray is the current gold standard for assessing osteoarthritis disease modification. Recently, concerns have been raised about this measure. However, there are limited longitudinal data comparing the predictive validity of MRI cartilage volume change and incident meniscal extrusion (IME) for X-ray change. The aim of this study was to determine whether change in these MRI indices over 2.6 years predicted change in JSW over 5 years in randomly selected community dwelling older adults.

Methods:

Participants (N=180) had X-rays and MRI's of the right knee at baseline and after 2.6 years for MRI and 5 years for X-ray. IME as well as articular cartilage volumes at baseline and 2.6 years were determined at the medial and lateral tibial and femoral compartments by MRI. Sagittal T1-weighted fat-suppressed MR images were obtained and processed on an independent computer work station. X-ray was performed using a standard fixed semi-flexed view and scored only on those with adequate alignment (N=150).

Results:

Participants were aged 50–80 years (mean 62 years, range 51–78), 49% were male. Medial and lateral cartilage volume reduced over time (medial -612 mL/year, p=<0.001, lateral -392mL/year, p<0.001), as did JSW (medial -0.048 mm/year, p=0.0043, lateral -0.12 mm/year, p<0.001). IME occurred in 7% (primarily medial). In multivariate analysis, change in compartment specific cartilage volume was a weak but significant predictor of change in JSW in both the medial (R25%, p=0.008) and lateral compartments (R22%, p=0.05). In the medial compartment, IME was a stronger predictor of change in JSW than cartilage volume loss (R2=14%, p<0.001).

In subgroup analysis by cartilage measurement site, change in tibial cartilage volume was not a significant predictor of change in JSW at the medial or lateral compartments (R20.4%, p=0.37; R22%, p=0.056). Change in femoral cartilage volume was weakly predictive of change in JSW in the medial (R22.5%, p=0.05) but not lateral compartments (R21.2%, p=0.17). In patients with prevalent radiographic osteoarthritis (n=84), change in cartilage volume had a better goodness of fit but was not significantly predictive of JSW change at the medial or lateral compartments, (R29.6%, p=0.132; R22.6%, p=0.16).

Conclusion:

Despite both outcome measures decreasing significantly from baseline, change in JSW was only weakly predicted by change in cartilage volume. This provides some evidence of face validity for X-ray. However, incident meniscal extrusion was a stronger contributor to change in JSW than cartilage volume loss at the medial compartment while over 80% of the variation in JSW change remains unexplained. Given that MRI examines cartilage directly while radiographs examine it indirectly, these results cast doubt on the validity of radiographs as a proxy measure of cartilage loss, suggesting it is time for a re-evaluation of the choice of key outcome measure for disease modifying trials.

To cite this abstract, please use the following information:
Hall, Joanna, Laslett, Laura, Pelletier, Johanne M., Pelletier, Jean Pierre, Abram, François, Ding, Chang-Hai, et al; Change in Knee Cartilage Volume and Incident Meniscal Extrusion As Predictors of Change in Joint Space Width of the Tibiofemoral Joint: 5 Year Longitudinal Study. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1625
DOI:

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