Longitudinal effect of vigorous physical activity on patella cartilage morphology in people without clinical knee disease.

OBJECTIVE: There are few data concerning possible long-term effects of physical activity on cartilage change in the patellofemoral compartment. We examined the effect of participation in vigorous physical activity on changes to patella cartilage over 2 years.
METHODS: A total of 297 healthy adults ages 50-79 years with no history of knee injury or symptoms were recruited from an existing study. Physical activity data were obtained by questionnaire at baseline (2003-2004). Patella cartilage volume and defects were determined by magnetic resonance imaging at baseline (2003-2004) and followup (2006-2007).
RESULTS: Participation in vigorous physical activity at baseline was associated with a reduced rate of patella cartilage volume loss (-21.2 mm(3) per annum [95% confidence interval (95% CI) -41.5, -1.0; P = 0.04]) and a trend toward less risk of worsening patella cartilage defects (odds ratio 0.4; 95% CI 0.2, 1.1 [P = 0.07]) over the subsequent 2 years. In the subgroup with no significant patella cartilage defects at baseline (n = 192), participation in vigorous physical activity was associated with a reduced annual rate of patella cartilage volume loss (95% CI -53.8, -7.8; P = 0.03) and a trend for fewer new patella cartilage defects (95% CI 0.1, 1.1; P = 0.08). No significant relationships were found between vigorous physical activity and cartilage volume change or defect progression in the subgroup with prevalent patella cartilage defects at baseline.
CONCLUSION: These observations suggest that vigorous physical activity is beneficial to patellofemoral joints for people without preexisting cartilage damage. Weight-bearing vigorous physical activity might, therefore, be useful in the prevention of patellofemoral osteoarthritis.