Introduction: Whether participation in long-term vigorous physical activity affects knee cartilage is unclear and may depend on the state of knee health. We examined the association between vigorous physical activity during a decade and the subsequent changes in knee cartilage among healthy adults. We then examined whether this effect differed in those with and without bone marrow lesions (BMLs), as an indicator of preclinical joint damage.
Methods: A total of 297 healthy adults age 50–79 yr were recruited. Physical activity was assessed via questionnaire at baseline (1990–1994) and at follow-up (2003–2004), and a score for persistence of vigorous physical activity score was determined. Each subject underwent knee magnetic resonance imaging in 2003–2004 and in 2006–2007. Cartilage volume, defects, and BMLs were measured using validated methods.
Results: Persistent participation in vigorous physical activity was associated with worsening of medial knee cartilage defects (odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.0–2.3). In the subgroup with BMLs, but not in those without BML, persistent vigorous physical activity was associated with a significant worsening of medial knee cartilage defects (OR = 3.4, 95% CI = 1.0–16.5) and a trend toward an increased rate of loss of medial knee cartilage volume (21.6 mm3·yr−1, 95% CI = −0.4 to 43.6).
Conclusions: In knees with BMLs, persistent participation in vigorous physical activity was associated with adverse cartilage changes in the medial compartment. This suggests that the long-term effects of vigorous physical activity may depend on the preexisting health of the joint.
1Department of Epidemiology and Preventive Medicine, Monash University Medical School, Alfred Hospital, Prahran, Victoria, AUSTRALIA; 2Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, School of Population Health, University of Melbourne, Carlton, Victoria, AUSTRALIA; and 3Cancer Epidemiology Centre, The Cancer Council Victoria, Carlton, Victoria, AUSTRALIA
A. J. Teichtahl and A. E. Wluka are joint first authors.
Address for correspondence: Flavia M. Cicuttini, M.B.B.S., F.R.A.C.P., Ph.D., Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, Vic 3004, Australia; E-mail: firstname.lastname@example.org.
Submitted for publication May 2011.
Accepted for publication November 2011.