Subchondral bone tissues in osteoarthritis of knee joint: a tetracycline labelling study

The patients with late osteoarthritis of the knee joint were given oral tetracycline to label the newly formed bone tissues before they were subjected to high tibial osteotomies or knee replacements. During the operation, the sclerotic subchondral bone tissue of the tibia and/or femur were procured. The bone specimens were processed into undecalcified sections and studied under fluorescence microscope. Apart from the autofluorescence of the trabeculae, strips of golden green labelled fluorescence of high intensity were noted along their peripheries, indicating that there were formatting and deposition of new bone along the periphery of the trabeculae. These new bone tissues were produced by the osteoblasts abutting the trabecular periphery. In the fatty tissues of the marrow interstices between the trabeculae, scattered dots and small flakes of golden green labelled fluorescence emerged at first. Then the labelled-fluorescent dots and flakes agglomerated into large pieces of more intense fluorescence with con