To clarify the normal range of articular cartilage volumes of the patella and femur in the human knee joints of healthy adults using three-dimensional magnetic resonance imaging and to analyze the correlation of the articular volumes with the background characteristics.

Fifty seven knees of 57 healthy volunteers aged from twenties to forties (30 males and 27 females), who had no past history of joint disease or trauma in the legs, were imaged by a fat-suppressed three-dimensional sequence (SPGR; 1.5T GE; Horizon LX 8.2.5) The obtained data were analyzed by 4 examiners independently with a computer workstation, and a average of the four was adopted as the articular volume. Analyzed characteristics factors of the volunteers were: age, body weight, height, leg length, foot size, circumference of the thigh and lower leg, quadriceps angle, foot angle, body-mass index, and general laxity.

The mean articular cartilage volume was 7.2 +- 1.6 ml. It was significantly larger in males than in females. Concerning the relationship between the volume and the characteristic factors, there was a significant correlation of the cartilage volume with the foot size in males (r=0.47), and with height, leg length and foot size in females (r=0.53, 0.60, 0.60, respectively), but no significant correlation with the other factors.

Conclusion. The articular cartilage volumes of the patella and femur was 7.2+- 1.6 ml. The size of skeletal structure, especially the skeletal size of the lower extremity, were assumed to be important factors in estimating cartilage volume.