Cell columns in articular cartilage physes questioned: a review

Objective: To report the outcome of a search of the literature for evidence in support of the published [Brown RA, Blunn GW, Salisbury JR, Byers PD. Two patterns of calcification in primary (physeal) and secondary (epiphyseal) growth cartilage. Clin Orthop 1993;294:318-24] observation that there are differences in the cellular organisation and ossification between the articular growth cartilage and the metaphyseal physis, i.e., dual patterns of ossification. Method: The search of the journal literature was by Medline. Many references came from found articles, and from textbooks. The source texts were at the libraries of the Royal Society of Medicine, The Wellcome Trust and the British Library. Results: (1) The search produced nine authors whose observations make up the bulk of the paper, which support the dual pattern of physes. (2) But there were also articles in favour of the single pattern of cellular organisation and ossification, in which, nevertheless, there were illustrations which were inconsistent with this, and favoured the duality. (3) The third section of the results mainly concerns the role of osteoclasts in the ossification process in articular physes. They are generally regarded as insufficient in number to play a solo part. Quantitative data about osteoclasts are limited; mathematical modelling is proposed as a more objective test. Conclusion: Objective, assessable criteria are presented in favour of a modification in our understanding of articular cartilage, and could, and should be augmented by further testing of the hypothesis. Some lines of enquiry are suggested. (C) 2005 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.