A biochemical analysis of subchondral bone of the medial tibial condyle in the normal state and in osteoarthritis and rheumatoid arthritis

Abstract

A chemical analysis has been carried out on specimens from the subchondral weightbearing area of the medial tibial condyle from 22 normal individuals, 14 individuals with osteoarthritis and 12 individuals with rheumatoid arthritis. In the normal group there was a decrease in density with advancing age. Over the age of 50 there was no significant difference between the groups. The content of collagen, calcium, phosphorus and magnesium in each bone specimen was calculated. When expressed in per cent of dry fat free bone there was no significant difference between the three groups. When calculations were made on the basis of content per volume tissue wet bone some differences were found. There was a tendency for a higher content of collagen in rheumatoid bone than in normal and osteoarthritic bone. The content of calcium was significantly higher in rheumatoid arthritis than in osteoarthritis; the same result was found in the analysis of phosphorus. In the normal group there was a decrease in phosphorus content with advancing age, this was also seen in the magnesium analysis.