[Study on the mechanical strength of the medial tibial condyle at the knee]

The purpose of this investigation was to disclose the detailed distribution of the compressive strength of the medial tibial condyle at the normal human knee. Specimens of cancellous bone were taken from 19 locations on the medial tibial plateaus. The compressive strength was measured by a testing machine of Instron type and compared with the ash weight. The compressive strength varied with the tested positions. The maximum strength was found in an area a little anterior to the center of the medial plateau. The strength was less in the center and decreased further in the exposed cartilage area other than the above two areas. The portion covered with meniscus showed the least strength. The ash weight was closely related to the compressive strength. These results indicate the functional adaptation of the internal structure of the subchondral bone to the load bearing. The changes in the compressive strength, according to age, were discussed. The 40-49 year age group showed the most strength, followed by the 20-39 year group. The compressive strength decreased considerably in the over 49-year group.