Caspase-3 may be employed as an early predictor for fracture-induced osteonecrosis of the femoral head in a canine model

The aim of the current study was to investigate the local expression of caspase-3 following femoral neck fractures in a canine model and to investigate its effect on the occurrence of fracture-induced osteonecrosis of the femoral head (ONFH). Eight dogs had surgically-induced femoral neck fractures on the left side which remained untreated. Radiological and histological examinations were employed to detect morphological changes of the femoral head. Immunohistochemical staining of caspase-3 was used to evaluate cell apoptosis, which may play an important role in ONFH. The results were compared to the normal side for statistical analysis. As a result, all eight dogs had ONFH, with non-union in five and malunion in three on radiological examination. Histologically, the untreated femoral heads developed osteonecrosis with an accumulation of bone marrow cell debris, empty lacunae and/or ghost nuclei in the lacunae, and an increase in the number of fat cells. Immunohistochemical staining of caspase-3 indicated that it was upregulated in fracture-induced ONFH two weeks postoperatively, which showed a statistical difference when compared to the normal side. In conclusion, the local expression of caspase-3 was upregulated in fracture-induced ONFH, suggesting that cell apoptosis is crucial in traumatic ONFH. Caspase-3 may therefore be employed as an effective and early predictor for fracture-induced ONFH.