Fat embolism and related effects during reamed and unreamed intramedullary nailing in a pig model

OBJECTIVES: To determine whether reamed or unreamed femoral intramedullary nailing is more adverse to pulmonary function, the authors compared three populations of healthy pigs, analyzing the biochemical and hemodynamic effects related to fat embolism. Likewise, the authors histologically evaluated the presence of bone marrow fat embolism in lungs, heart, kidney, brain, and retina. DESIGN: Randomized, experimental model. SETTING: Laboratory. PARTICIPANTS: Twenty-five male Duroc Jersey adult healthy pigs divided in three groups. INTERVENTION: Reamed and unreamed intramedullary nailing. OUTCOME MEASUREMENTS: Biochemical, hemodinamical, and histologic analysis. METHODS: In the first group of ten pigs, a reamed nail was inserted; in the second group of ten specimens, the authors placed an unreamed nail; and in the third group of five animals (control), only the surgical approach was made without opening the medullary cavity. RESULTS: The authors did not find statistically significant differences in pulmonary function between the reamed and unreamed group in the hemodynamic, biochemical, and histopathologic parameters evaluated. The histologic analysis of the lung tissue revealed a statistically significant difference between the nailed groups and the control (P < 0.04). CONCLUSIONS: In this animal model, the results indicate that pulmonary changes and fat embolization during intramedullary nailing occur to the same degree in reamed and in unreamed femurs.