The histological features of Anteromedial Gonarthrosis — The comparison of two grading systems in a human phenotype of osteoarthritis

Rajesh Rout, Stephen McDonnell, Richard Benson, Nicholas Athanasou, Andrew Carr, Helen Doll, Harinderjit S. Gill, David W. Murray, Philippa A. Hulley, Andrew J. Price

Research output: Contribution to journalArticle

21 Citations (Scopus)


Anteriorly there is a full thickness cartilage defect, with transition to a partial thickness defect, becoming full thickness cartilage in the posterior third of the tibial plateau. The retained posterior cartilage is macroscopically normal. This study characterises the histological changes of AMG and examines the usefulness of two histological assessment tools.
Sixteen unicompartmental resection specimens of patients with primary AMG were assessed. Samples were stained with Haematoxylin and Eosin and Safranin-O stains and scored using the modified Mankin grade, and the OOCHAS assessment tool. Each specimen was assessed at five regions along the antero-posterior axis starting from the exposed bone to the region of macroscopically normal cartilage.

From anterior to posterior the staining showed a consistent increase in structural integrity and cellularity of the cartilage, matched by a qualitative increase in GAG content. Mean modified Mankin and OOCHAS scores showed a progressive decrease in grade (p<0.001). The OOCHAS grade had a good correlation with the modified Mankin grade (ρ=0.886) and there was good intra- and inter-observer variability with both assessment tools.

We conclude that there is progressive decrease in histological score from anterior to posterior in AMG and that the macroscopically normal cartilage seen posteriorly is histologically normal. Both the modified Mankin and OOOCHAS assessment tools are useful in histological grading but we found the OOCHAS easier and quicker to use. We propose that AMG represents a spatial model of progressive cartilage damage.
Original languageEnglish
Pages (from-to)172-176
Number of pages5
JournalThe Knee
Issue number3
Publication statusPublished - Jun 2011

Cite this