Study on the mechanical strength of the medial tibial condyle of the rheumatoid knee

Abstract

The distribution of mechanical strength in the medial tibial condyle of frozen rheumatoid arthritis (RA) knees was investigated. Specimens were taken from 17 medial tibial condyle sites and the compressive strength was measured. The compressive strength distribution for the normal human knee was investigated using the same method. The results for the normal and RA knees were compared.The compressive strength of the RA knee varied with the medial tibial condyle site. The greatest compressive strength occurred slightly anterior to the center. The compressive strength distribution of the RA knee was very similar to that of the normal knee, but the maximum value was only about 73% of the normal knee's. Involvement of RA activity, reduced activity in daily living (ADL) and especially disuse atrophy were suspected. Correlations of the patients' ages, RA duration, ADL, steroid use and load bearing with the compressive strength were further studied.