Risk Factors of Loss of Cartilage Volume in Knee Osteoarthritis Patients
Risk Factors of Loss of Cartilage Volume in Knee Osteoarthritis Patients
The objective of this study was to identify, on a symptomatic knee osteoarthritis (OA) cohort, the risk factors associated with the progression of the disease. More specifically, we investigated the correlation between knee cartilage volume loss from subregions over the span of 24 months by means of quantitative magnetic resonance imaging (qMRI) with demographic, clinical, radiological, and MRI structural changes.
A cohort of 107 patients with knee OA selected from a large trial evaluating the effect of a bisphosphonate underwent x-rays and MRI of the knee at baseline and 24 months. Joint space width (JSW) and joint space narrowing (JSN) and cartilage volume loss over time in subregions of the tibial plateaus and femoral condyles were quantitated. Structural changes in the subchondral bone (hypersignal) and in the menisci (tear and extrusion) were also evaluated.
The greatest cartilage volume loss was found in the medial compartment, and risk factors included female gender, JSW, meniscal lesions, and bone changes at baseline. Subregion analysis revealed that the greatest cartilage volume loss at 24 months was found in the central area of the medial tibial plateau (15%; p < 0.0001) and of the medial femoral condyle (12%; p < 0.0001). These findings were associated with the presence at baseline of meniscal extrusion, particularly severe meniscal extrusion, medial and severe meniscal tear, bone hypersignal, high body mass index (BMI), smaller JSW, increases in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and patient global scores over time, and greater JSN. Parameters predicting medial central femoral condyle cartilage volume loss at 24 months were lateral meniscal tear, SF-36 and BMI at baseline, and JSN. At the medial central tibial plateau, the parameters were severe meniscal extrusion, severe lateral meniscal tear, and bone hypersignal in the lateral compartment at baseline, and WOMAC pain change.
Meniscal damage and bone changes are the features most closely associated with the greatest subregional cartilage volume loss. Interestingly, for the first time, JSN was strongly associated with cartilage loss in the central areas of plateaus and condyles. This study also further confirms the correlation between cartilage volume loss and JSN and symptomatic changes at 24 months.
The structural changes in knee osteoarthritis (OA) are characterized mainly by the progressive erosion and loss of articular cartilage. These changes are often associated with additional structural changes such as subchondral bone lesions, which include remodelling and cysts, and alterations in the menisci, which include degeneration, tear, and extrusion. Conventional x-rays have been used and continue to be used to assess some of these changes, particularly in the evaluation of disease progression. However, the use of x-rays to assess and quantify structural changes over time does present some serious limitations, including the fact that this technology does not permit direct visualization of cartilage).
In the last decade, remarkable progress in the development of imaging technology has been made. Magnetic resonance imaging (MRI) now allows not only the direct visualization of joint structure but also the quantitative assessment of changes over time. A number of semiquantitative scoring systems and quantitative technologies have been developed to achieve this goal. Most of the work has concentrated on the measurement of cartilage volume/thickness and the assessment of changes to evaluate the evolution of OA lesions in cross-sectional and longitudinal studies. Some of these studies have been highly instrumental in providing a significant amount of new information. For instance, they have shown that disease progression is not consistent among patients suffering from knee OA and that a number of factors are associated with a risk of more aggressive progression. These risk factors include higher body mass index (BMI), meniscal tear/extrusion, and subchondral bone marrow hypersignal or edema. To date, correlations between the global or regional loss of cartilage and disease symptoms or patient function have seldom been studied and correlations between x-ray and MRI data with respect to cartilage loss are recognized in general as not very strong). Studies using quantitative MRI (qMRI) have demonstrated that the loss of cartilage volume in patients with knee OA is generally progressive over time and is usually greater in the medial compartment than the lateral compartment. However, in these patients, very little information is available on the evolution of cartilage loss over time in the more focal regions, such as the subregions of the knee compartments, and on whether patients with rapid versus slow disease progression have the same evolution. Even less information is available on the relationship between these lesions and associated risk factors, disease signs and symptoms, and x-ray changes. Therefore, the main aim of this study was to identify the structural changes in OA, which could explain the progression of symptoms, and thereby provide a better understanding of the natural evolution of the disease. This information is essential to the design of clinical trials and the development of new therapeutic disease-modifying OA drug (DMOAD) strategies.
Abstract and Introduction
Abstract
The objective of this study was to identify, on a symptomatic knee osteoarthritis (OA) cohort, the risk factors associated with the progression of the disease. More specifically, we investigated the correlation between knee cartilage volume loss from subregions over the span of 24 months by means of quantitative magnetic resonance imaging (qMRI) with demographic, clinical, radiological, and MRI structural changes.
A cohort of 107 patients with knee OA selected from a large trial evaluating the effect of a bisphosphonate underwent x-rays and MRI of the knee at baseline and 24 months. Joint space width (JSW) and joint space narrowing (JSN) and cartilage volume loss over time in subregions of the tibial plateaus and femoral condyles were quantitated. Structural changes in the subchondral bone (hypersignal) and in the menisci (tear and extrusion) were also evaluated.
The greatest cartilage volume loss was found in the medial compartment, and risk factors included female gender, JSW, meniscal lesions, and bone changes at baseline. Subregion analysis revealed that the greatest cartilage volume loss at 24 months was found in the central area of the medial tibial plateau (15%; p < 0.0001) and of the medial femoral condyle (12%; p < 0.0001). These findings were associated with the presence at baseline of meniscal extrusion, particularly severe meniscal extrusion, medial and severe meniscal tear, bone hypersignal, high body mass index (BMI), smaller JSW, increases in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and patient global scores over time, and greater JSN. Parameters predicting medial central femoral condyle cartilage volume loss at 24 months were lateral meniscal tear, SF-36 and BMI at baseline, and JSN. At the medial central tibial plateau, the parameters were severe meniscal extrusion, severe lateral meniscal tear, and bone hypersignal in the lateral compartment at baseline, and WOMAC pain change.
Meniscal damage and bone changes are the features most closely associated with the greatest subregional cartilage volume loss. Interestingly, for the first time, JSN was strongly associated with cartilage loss in the central areas of plateaus and condyles. This study also further confirms the correlation between cartilage volume loss and JSN and symptomatic changes at 24 months.
Introduction
The structural changes in knee osteoarthritis (OA) are characterized mainly by the progressive erosion and loss of articular cartilage. These changes are often associated with additional structural changes such as subchondral bone lesions, which include remodelling and cysts, and alterations in the menisci, which include degeneration, tear, and extrusion. Conventional x-rays have been used and continue to be used to assess some of these changes, particularly in the evaluation of disease progression. However, the use of x-rays to assess and quantify structural changes over time does present some serious limitations, including the fact that this technology does not permit direct visualization of cartilage).
In the last decade, remarkable progress in the development of imaging technology has been made. Magnetic resonance imaging (MRI) now allows not only the direct visualization of joint structure but also the quantitative assessment of changes over time. A number of semiquantitative scoring systems and quantitative technologies have been developed to achieve this goal. Most of the work has concentrated on the measurement of cartilage volume/thickness and the assessment of changes to evaluate the evolution of OA lesions in cross-sectional and longitudinal studies. Some of these studies have been highly instrumental in providing a significant amount of new information. For instance, they have shown that disease progression is not consistent among patients suffering from knee OA and that a number of factors are associated with a risk of more aggressive progression. These risk factors include higher body mass index (BMI), meniscal tear/extrusion, and subchondral bone marrow hypersignal or edema. To date, correlations between the global or regional loss of cartilage and disease symptoms or patient function have seldom been studied and correlations between x-ray and MRI data with respect to cartilage loss are recognized in general as not very strong). Studies using quantitative MRI (qMRI) have demonstrated that the loss of cartilage volume in patients with knee OA is generally progressive over time and is usually greater in the medial compartment than the lateral compartment. However, in these patients, very little information is available on the evolution of cartilage loss over time in the more focal regions, such as the subregions of the knee compartments, and on whether patients with rapid versus slow disease progression have the same evolution. Even less information is available on the relationship between these lesions and associated risk factors, disease signs and symptoms, and x-ray changes. Therefore, the main aim of this study was to identify the structural changes in OA, which could explain the progression of symptoms, and thereby provide a better understanding of the natural evolution of the disease. This information is essential to the design of clinical trials and the development of new therapeutic disease-modifying OA drug (DMOAD) strategies.
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