Association of prevalent and incident knee cartilage defects with loss of tibial and patellar cartilage: a longitudinal study.

OBJECTIVE

To describe the association between prevalent and incident knee cartilage defects and loss of knee cartilage in male and female adults.

METHODS

A convenience sample of 325 subjects (mean age 45 years; age range 26-61 years) was evaluated at baseline and approximately 2 years later. Knee cartilage volume, cartilage defect scores (0-4 scale), and joint surface area were determined using T1-weighted fat-suppression magnetic resonance imaging techniques. Height, weight, and radiographic evidence of osteoarthritis were measured by standard protocols.

RESULTS

Multivariable analysis revealed that baseline cartilage defect scores at the medial tibia, lateral tibia, and patella had a dose-response association with the annual rate of change in knee cartilage volume at the corresponding site (beta = -1.3% to -1.2% per grade; P < 0.05 for all comparisons). In addition, an increase in knee cartilage defect score (change of > or =1) was associated with higher rates of knee cartilage volume loss at all sites (beta = -1.9% to -1.7% per year; P < 0.01 for all comparisons). Furthermore, a decrease in the knee cartilage defect score (change of less than or equal to -1) was associated with an increase in knee cartilage volume at all sites (beta = 1.0% to 2.7% per year; P < 0.05 for all comparisons).

CONCLUSION

Prevalent knee cartilage defects are predictive of compartment-specific cartilage loss over 2 years. Both increases and decreases in knee cartilage defects are associated with changes in knee cartilage volume, which implies a potential for reversal of knee cartilage loss.