Keegan Hovis, Presenter: Nothing to Disclose

Christoph Stehling, Abstract Co-Author: Nothing to Disclose

Jean-Baptiste Pialat, Abstract Co-Author: Nothing to Disclose

Michael Nevitt, Abstract Co-Author: Nothing to Disclose

Charles McCulloch, Abstract Co-Author: Nothing to Disclose

Thomas M. Link MD, Abstract Co-Author: Consultant, General Electric Company

To evaluate the effects of exercise, strength training and knee-bending activities on knee cartilage T2 values and morphologic abnormalities in asymptomatic subjects from the Osteoarthritis Initiative (OAI) incidence and normal cohorts.

We analyzed 133 subjects with knee osteoarthritis (OA) risk factors (incidence cohort) and 33 age and BMI-matched controls. The leisure activity component of the Physical Activity Scale for the Elderly (PASE) was stratified by exercise and strength training levels. Exercise groups included E1: sedentary, E2: light exercisers and E3: moderate-strenuous exercisers. Strength training groups included S1: none, S2: minimal and S3: frequent. Knee-bending activities were also analyzed. MRI at 3T was performed using intermediate-weighted fast spin-echo and T2 mapping sequences. Five cartilage compartments – patella, medial femur/tibia (MF/MT), lateral femur/tibia (LF/LT) – were segmented on T2 maps. Two radiologists analyzed all images and graded cartilage and meniscus using a modified whole organ MRI score (WORMS). Statistical significance between the groups was determined using a multiple linear regression model, chi-square and independent t-tests.

Incidence cohort light exercisers had lower T2 values than sedentary and moderate-strenuous exercisers, most consistently in LT (38.0±3.1 vs. 39.7±3.4 and 40.2±3.3 ms, p<0.001). Subjects with minimal strength training had lower T2 values than those with none or frequent strength training in the patella (42.1±3.1 vs. 44.3±4.3 and 45.0±3.0 ms, p=0.022) and also in males in MF (p=0.044). Moderate-strenuous exercise in females who participated in any level of strength training was correlated with higher T2 values in MF (p<0.001). The normal cohort showed no significant differences when analyzed by these activities. Knee-bending activities were correlated with higher T2 values in both cohorts and higher WORMS in the incidence cohort (p<0.02).

Light exercise appears to protect against cartilage degeneration in subjects with OA risk factors, and moderate-strenuous exercise in females seems to be detrimental. Exercise and strength training levels, however, do not seem to affect subjects without OA risk factors. Frequent knee-bending activities appear to be detrimental to knee cartilage in both cohorts.

Modifying physical activity may be an effective intervention to prevent cartilage degeneration.

Hovis, K, Stehling, C, Pialat, J, Nevitt, M, McCulloch, C, Link, T, Association of Exercise, Strength Training, and Knee-bending Activities with Knee Cartilage T2 Values and WORMS Using 3 T MRI in Asymptomatic Subjects with and without Osteoarthritis Risk Factors.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9003905.html