Morphological and morphometrical alterations of the osteochondral junction in perinatal necropsies.

Infants who die during the perinatal period could present the following upon examination of the ribs: alterations of the osteochondral junction (OCJ) that could be related to intrauterine growth restriction, placental alterations, maternal disorders, and congenital abnormalities. The aim of this study was to identify the morphological alterations of the OCJ in the autopsied infants and the factors associated with its pathogenesis. The OCJ from 254 infants were sequentially autopsied and analyzed. Hematoxylin-eosin and blue Masson's trichrome stains were used for examination. The expression in the chondrocytes of the cartilage oligomeric matrix protein (COMP) was measured using a polyclonal antibody. There were 199 (78.3%) cases with normal OCJ and 55 (22%) cases with alterations; among these, 38 (14.9%) cases have an increased cartilage matrix at the free bone marrow zone of the OCJ (ICM), 10 (3.9%) cases have a bizarre pattern (BZ), 5 (2%) cases have a bone tissue formation closing de growth channels (MCO) of the OCJ, and 2 (0.8%) cases have bone marrow cells encroaching the free bone marrow zone. The length of the proliferative zone was different in the groups with alterations of the OCJ (P < .001), being higher in the group of patients with MCO and ICM (P < .05). In the group with BZ, the length was smaller (P < .05). The analysis of the OCJ is important in the autopsies performed at the perinatal period, and this study contributes for a better understanding of the mechanisms related to the etiology of these alterations.