Bone Abstracts

Only minor literature on histopathologic changes in Blount’s disease is available. This study presents the histologic findings of biopsies harvested from the medial and lateral part of the proximal tibia during the W/M serrated osteotomy in patients with infantile Blount’s disease, performed in Ghana. In this study it is hypothesized that the medial metaphyseal area in these children will present a different histological morphology compared to the lateral metaphyseal area.

During two unilateral and two bilateral W/M serrated osteotomies, biopsies of the medial and lateral cortex of the proximal part of the serrations were taken. Patients were included prospectively. The specimens were fixed in formalin, decalcified, embedded in paraffin, sectioned and stained with hematoxylin and eosin, and Safranine O. All specimens were evaluated by light microscopy.

From the medial obtained specimens, 50% showed presence of endochondreal ossification and 33% showed subperiosteal islands of hypertrophied chondrocytes (Figure 1 A–B). In the lateral aspect of the metaphyseal bone no abnormalities were observed.

In conclusion, in patients with infantile Blount’s disease disturbed endochondral ossification in the medial part of the proximal tibial metaphysis is observed.

Disclosure: The authors declared no competing interests.

Figure 1 A-B Islands of hypertrophied chondrocytes. A-B. Sections from the medial site of the tibia were stained by Safranin-O/Fast Green to determine the presence of cartilaginous tissue. Bar = 100 μm for first micrograph (A) and bar = 50 μm for second micrograph (B). These figures show islands of densely packed chondrocytes which colour orange like after the Safranine-O/Fast Green staining due to the presence of glycosaminoglycans in cartilaginous tissue.