The cartilage thickness distribution in the tibiofemoral joint and its correlation with cartilage-to-cartilage contact.

OBJECTIVE: The objective of this study was to investigate whether regions of cartilage in the tibiofemoral joint where cartilage-to-cartilage contact occurred was thicker than other regions.
DESIGN: In vivo human subjects.
BACKGROUND: The thickness of the cartilage in the knee has been investigated in various studies. However, the factors that influence the thickness distribution within the joint remain unclear.
METHODS: Six healthy living knees (5 male, 1 female, average age = 27) were scanned using magnetic resonance imaging. Three-dimensional models of the tibial and femoral cartilage layers were created. The cartilage thickness distribution was compared between regions where cartilage-to-cartilage contact was observed during in vivo weightbearing flexion and regions with no contact.
RESULTS: The regions with cartilage-to-cartilage contact were significantly thicker than the regions without cartilage-to-cartilage contact (P < 0.05). On the medial condyle, the cartilage-to-cartilage contact regions were up to 40% thicker than regions with no contact. On the lateral femoral condyle, the maximum difference between these regions was 20%. On the tibial plateau, the maximal differences between regions with and without cartilage-to-cartilage contact were found to be 40% on the medial side and 50% on the lateral side.
CONCLUSIONS: The data suggested that in normal knees, the cartilage was thicker in regions where cartilage-to-cartilage contact was present. Future studies should investigate the effects of in vivo loading on cartilage maintenance and growth. Relevance Injuries that alter knee kinematics might load regions of the joint where the cartilage is thinner. This might alter the stress distributions within the cartilage.