Fig. 3

Sampling sites and normal ligament structure versus metaplastic tenocytes / chondroid metaplasia. Caudal view 3D reconstruction of a barium perfused en block preparation of the patella; the patellar ligaments; and the tibial tuberosity of case no. 2; perfused vessels are seen in white; the ligament outline is seen in blue. Red boxes illustrate the location for the tissue blocks harvested from each ligament, here illustrated for the intermediate patellar ligament. B-D Photomicrographs illustrating normal ligament structure at 2.5x, 10 × and 40 × magnification, respectively. Polygonal fascicles consisting of collagen bundles with scattered tenocytes are seen separated by connective tissue septa (endotenon) carrying blood vessels, lymph vessels and nerves. Tenocyte nuclei are spindle shaped (type 1). E–G Photomicrographs illustrating metaplastic tenocytes / chondroid metaplasia at 2.5x, 10 × and 40 × magnification, respectively. The normal extracellular matrix has been replaced by chondroid matrix (asterisks), and tenocyte nuclei are rounded, located in semi-lacunae