Knee cartilage loss in symptomatic knee osteoarthritis over 4.5 years

Anita E Wluka,Fahad Hanna,Andrew Forbes,Flavia M Cicuttini,Yuanyuan Wang,Graeme Jones

doi:10.1186/ar1962

Abstract

The objective of this study was to describe the rate of change in knee cartilage volume over 4.5 years in subjects with symptomatic knee osteoarthritis (OA) and to determine factors associated with cartilage loss. One hundred and five subjects were eligible for this longitudinal study. Subjects' tibial cartilage volume was assessed by magnetic resonance imaging (MRI) at baseline, at 2 years and at 4.5 years. Of 105 subjects, 78 (74%) completed the study. The annual percentage losses of medial and lateral tibial cartilage over 4.5 years were 3.7 ± 4.7% (mean ± SD; 95% confidence interval 2.7 to 4.8%) and 4.4 ± 4.7% (mean ± SD; 95% confidence interval 3.4 to 5.5%), respectively. Cartilage volume in each individual seemed to track over the study period, relative to other study participants. After multivariate adjustment, annual medial tibial cartilage loss was predicted by lesser severity of baseline knee pain but was independent of age, body mass index and structural factors. No factors specified a priori were associated with lateral cartilage volume rates of change. Tibial cartilage declines at an average rate of 4% per year in subjects with symptomatic knee OA. There was evidence to support the concept that tracking occurs in OA. This may enable the prediction of cartilage change in an individual. The only significant factor affecting the loss of medial tibial cartilage was baseline knee pain, possibly through altered joint loading.

Highlights

Clinicians, faced with a patient with osteoarthritis (OA), have taken a somewhat nihilistic approach with respect to the modification of structural disease progression
The objective of this study was to describe the rate of change in knee cartilage volume over 4.5 years in subjects with symptomatic knee osteoarthritis (OA) and to determine factors associated with cartilage loss
We have extended the observation of a cohort of community-dwelling subjects with predominantly mild symptomatic knee OA to determine the change in knee cartilage volume in subjects with knee OA over 4.5 years [10], and factors that may affect this

Summary

Introduction

Clinicians, faced with a patient with osteoarthritis (OA), have taken a somewhat nihilistic approach with respect to the modification of structural disease progression. Knee cartilage volume measured with MRI is one such approach, which shows promise as a method of quantifying disease severity in OA. It is a valid and reproducible measure of articular cartilage [5,7]. It correlates inversely with radiographic grade of disease, such that subjects with knee OA have less knee cartilage than normal healthy subjects [8]. It is possible to estimate normal cartilage volume to distinguish diseased knees from healthy ones [8,9]

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