Comprehensive investigation into the endothelium in Legg-Calvé-Perthes with clinical, molecular, and histopathological examinations reveals arteriolar wall thickening and proliferative synovitis: A preliminary report.

BACKGROUND AND STUDY AIMS: The exact cause of spontaneously healing idiopathic osteonecrosis in the Legg-Calvé-Perthes disease (LCPD) is still unknown. Although it is postulated that thrombotic processes that occur as a result of genetic, epigenetic and environmental factors are at the forefront, the root cause cannot be fully elucidated. The aim of this study is to investigate underlying endothelial inflammation as a trigger of these pathophysiological mechanisms leading to LCPD.

MATERIALS: The levels of ICAM-1 and E-selectin in the local blood vessels around the femoral neck and peripheral veins of seven surgically treated LCPD patients and similar age controls were compared. These were reviewed together with the clinical and histopathological findings of the LCPD patients.

RESULTS

There were no statistically significant differences between each group's ICAM-1 and E-selectin levels in the femoral neck region or the peripheral vessels (p>0.05). Histopathological examination revealed arterioles with thickened walls and luminal obliteration. Chronic synovitis with plasma cell and lymphocyte infiltration of different severity was detected in more than half of the patients. Proliferative synovitis with papillary proliferations was seen in two patients. The patients who had these histological findings also had endothelial marker levels above the cohort mean.

CONCLUSIONS

In summary, this study provided a comprehensive examination of LCPD patients. We observed arteriolar involvement and proliferative synovitis in multiple patients in the group.

CLINICAL RELEVANCE: This study provides important information about the pathophysiological basis of LCPD by combining clinical, molecular, and histopathological data. It is a comprehensive study in an uncommon population of surgically treated LCPD patients and similar age controls. To our knowledge, the findings of proliferative synovitis and arteriolar wall thickening have not been previously reported in the LCPD literature.