Quantitative structural organization of normal adult human articular cartilage.
OBJECTIVE
Data pertaining to the quantitative structural features and organization of normal articular cartilage are of great importance in understanding its biomechanical properties and in attempting to establish this tissue's counterpart by engineering in vitro. A comprehensive set of such baseline data is, however, not available for humans. It was the purpose of the present study to furnish the necessary information.


METHODS
The articular cartilage layer covering the medial femoral condyle of deceased persons aged between 23 and 49 years was chosen for the morphometric analysis of cell parameters using confocal microscopy in conjunction with unbiased stereological methods. The height of the hyaline articular cartilage layer, as well as that of the calcified cartilage layer and the subchondral bone plate, were also measured.


RESULTS
The mean height of the hyaline articular cartilage layer was found to be 2.4mm, the volume density of chondrocytes therein being 1.65%, the number of cells per mm(3) of tissue 9626 and the mean cell diameter 13 microm. Other estimators (including matrix mass per cell and cell profile density) were also determined.


CONCLUSIONS
A comparison of these normal human quantitative data with those published for experimental animals commonly used in orthopaedic research reveals substantial differences, consideration of which in tissue engineering strategies destined for human application are of paramount importance for successful repair.
M. E. Müller-Institute for Biomechanics, University of Bern, Murtenstrasse 35, P.O. Box 30, Switzerland. hunziker@mem.unibe.ch
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D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology* / Q000166:cytology; D002452:Cell Count; D048429:Cell Size; D019902:Chondrocytes / Q000166:cytology; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D012016:Reference Values