PURPOSE:

To investigate the effects of exercise on patellar cartilage using T2 relaxation time mapping of MRI in postmenopausal women with mild patellofemoral joint osteoarthritis (OA).

METHODS:

Eighty postmenopausal women (mean age: 58 y (SD 4.2)) with mild knee osteoarthritis were randomized to either a supervised progressive impact exercise program three times a week for 12 months (n = 40) or to a non-intervention control group (n = 40). The biochemical properties of cartilage were estimated using T2 relaxation time mapping, a parameter sensitive to collagen integrity, collagen orientation and tissue hydration. Leg muscle strength and power, aerobic capacity and self-rated assessment by the Knee Injury and Osteoarthritis Outcome Score (KOOS) were also measured.

RESULTS:

Post intervention the full-thickness patellar cartilage T2 values had medium size effect (d= 0.59; 95% CI: 0.16 to 0.97, p=0.018), the change difference was 7% greater in the exercise group compared to the control group. In the deep half of tissue, the significant exercise effect was in medium size (d= 0.56; 95% CI: 0.13 to 0.99, p=0.013), the change difference was 8% greater in the exercise group compared to the controls. Also, significant medium size T2 effects were found in the total lateral segment, lateral deep and lateral superficial zone in favor of the exercise group. Extension force increased by 11% (d=0.63, p=0.006) more and maximal aerobic capacity by 4% (d=0.55, p=0.028) more in the exercise group than controls. No changes in KOOS emerged between the groups.

CONCLUSIONS:

Progressively implemented high-impact and intensive exercise created enough stimuli and had favorable effects both on patellar cartilage quality and physical function in postmenopausal women with mild knee OA.