THE DISTRIBUTION OF CARTILAGE THICKNESS IN THE KNEE-JOINTS OF OLD-AGED INDIVIDUALS - MEASUREMENT BY A-MODE ULTRASOUND

Objective. To provide data on the normal distribution of cartilage thi ckness in the knee joints of old-aged individuals. Design. The accurac y and reproducibility of cartilage thickness measurements were evaluat ed with A-mode ultrasound, and the cartilage thickness distribution wa s examined throughout both knee joints of nine individuals aged betwee n 62 and 94 yr. Background. Data on the variation of cartilage thickne ss in the joint surfaces are relevant for the design of computer model s of diathrodial joints and for surgical and arthroscopic procedures, particularly the calculation of cartilage material properties from ind entation tests. Methods. A 12.5 MHz A-mode ultrasound transducer was u sed, and after determining the accuracy and reproducibility of the sys tem in comparison with CT arthrography and anatomical sections, the ca rtilage thickness was measured throughout the knee at 256 coordinate p oints. Results. A-mode ultrasound yields results consistent with estab lished methods. The cartilage thickness is distributed regularly in th e knee-joint of older individuals. However, the absolute values are co nsiderably lower than those previously reported for younger people, th e mean (and maximal) thickness being 2.0 mm (3.3 mm) in the patella, 1 .9 mm (3.3 mm) in the femur, and 1.9 mm (3.5 mm) in the tibia. Conclus ion. If the results of computer models or surgical strategies are to b e applied to the demographically important group of older individuals, the typical distribution of articular cartilage thickness in this gro up should be taken into consideration. Relevance No quantitative data with regard to the typical distribution of knee joint cartilage thickn ess of older individuals have been reported in the literature: These d ata are, however, relevant for the design of computer models of diarth rodial joints, operative strategies, and the calculation of cartilage material properties from arthroscopic indentation tests. (C) 1998 Else vier Science Ltd. All rights reserved.