Physical activity is associated with magnetic resonance imaging–based knee cartilage T2 measurements in asymptomatic subjects with and those without osteoarthritis risk factors

Abstract

Objective To evaluate the association of exercise and knee-bending activities with magnetic resonance (MR)-based knee cartilage T2 relaxation times and morphologic abnormalities in asymptomatic subjects with and without osteoarthritis (OA) risk factors from the Osteoarthritis Initiative. Methods We studied 128 subjects with knee OA risk factors and 33 normal controls aged 45–55 years, with a body mass index of 18–27 kg/m2, and no knee pain. Subjects were categorized by exercise level, using the leisure activity component of the Physical Activity Scale for the Elderly, and by self-reported frequent knee-bending activities. Two radiologists graded the cartilage using the Whole Organ MR Imaging Score (WORMS) of right knee MR images. Cartilage was segmented and compartment specific T2 values were calculated. Statistical significance between the exercise groups and knee-bending groups was determined using multiple linear and logistic regression models. Results Among subjects with risk factors, light exercisers had lower T2 measurements than sedentary and moderate-strenuous exercisers (p=0.001); in women, moderate-strenuous exercise was associated with higher T2 values (p=0.001). Subjects without risk factors displayed no significant differences in T2 values by exercise. However, frequent knee-bending activities were associated with higher T2 values in both groups (p<0.02) and more severe cartilage lesions in the group with risk factors (p<0.001). Conclusions In subjects at risk for OA, light exercise was associated with low T2 measurements, whereas moderate-strenuous exercise in women was associated with high T2 values. Higher T2 values and WORMS grades were also found in frequent knee-benders and suggest greater cartilage degeneration in these individuals.

Imaging research results from the Osteoarthritis Initiative (OAI): a review and lessons learned 10 years after start of enrolment

“…A U-shaped association between physical activity levels and cartilage lesions was suggested: intermediate activity levels were associated with the lowest T2 (ie, the healthiest cartilage), suggesting a protective impact of moderate activity 89 91. T2 also differed between subjects with OA risk factors and those without; T2 was associated with Body Mass Index (BMI)92 93 and greater BMI also was associated with greater incidence and progression of cartilage lesions 94.…”

“…T2 also differed between subjects with OA risk factors and those without; T2 was associated with Body Mass Index (BMI)92 93 and greater BMI also was associated with greater incidence and progression of cartilage lesions 94. Further studies found trochlear dysplasia95 and ACL abnormalities associated with cartilage degenerative change 91. While T2 was found to have potential for monitoring early disease, it may be less useful in monitoring disease progression once cartilage defects have occurred 96…”

T2 mapping of the articular cartilage in the ankle: Correlation to the status of anterior talofibular ligament

“…9e11 These early changes are quantifiable through T2 value mapping, and include increases in water content and alterations in the collagen content and architecture. 11,12 T2 values have been shown in different studies to be sensitive to cartilage alterations, as seen in OA 9,10,13,14 or after surgical cartilage repair procedures. 15,16 Because the use of T2 value measurements allows the detection of early biochemical shifts in the cartilage matrix prior to irreversible morphological changes, it is a technique that may be well suited to evaluate the effects of risk factors, such as ligament injury, on ankle cartilage health.…”

Effects of Exercise on Patellar Cartilage in Women with Mild Knee Osteoarthritis

“…High T 2 values correlate with histological degeneration of cartilage, implying increased free water content and collagen disorientation (8,22). However, in subjects with high OA risk, light exercise has been associated with better cartilage quality (16).…”