Reduction of fat embolic risks in total hip arthroplasty using cannulated rasps for preparation of femoral canal / 中华骨科杂志

ABSTRACT

Objective To describe the effect of cannualted rasps in reduc in g the fat embolic risks during preparation for femoral canal in experimental tot al hip arthroplasty. Methods Twelve mongrels were used to perform resection of b ilateral femoral heads, and randomly assigned to one of two groups with six each . In experiment group, impacting cannulated rasp was used in preparing femoral c anal; while, in control group, impacting traditional rasp was used. Both the ras ps were of same shape; however, there was a 4 mm diameter canal inside the cannu lated rasp connecting its two ends. A bone hole was made through the lateral fem oral cortex to the femoral canal at a point 12 cm distal to the greater trochant er in order to measure the intramedullary pressure of femoral canal when the fem oral canal was prepared with either rasp. The pathology of the postmortem pulmon ary tissue was analyzed. Using quantitative morphometry, the size of fat embolus in the lung tissues and the volume proportion of lung tissues occluded by fat w ere measured respectively. The statistical differences between the two groups we re analyzed using t test. Results In control group, the intramedullary pressure during preparation of femoral canal with traditional rasp increased with a peak of (34.5?10.2)kPa, pulmonary fat emboli were found in all mongrels, the volum e proportion of postmortem lung tissue occluded by fat was 0.64%, and pulmonary arterial pressure increased to (2.2?0.4)kPa[the normal value was (0.8?0.3 )kPa]; while in the experiment group, the intramedullary pressure peak increas ed to (22.4?7.7)kPa, significantly lower than that of the control group; the volume proportion of lung tissue occluded by fat was 0.21% which was also signif icantly lower than that of the control group, and pulmonary arterial pressure wa s (1.7?0.4)kPa. The differences between the two groups were significant in al l measured values. Conclusion The present study suggests that conventional prepa ration of canal can cause an increase of intramedullary pressure, which may lead to pulmonary fat embolism and cardiopulmonary impairment. However, the cannulat ed rasp can decrease the volume proportion of lung tissue occluded by fat and al leviate the influence of preparation of canal on cardiopulmonary function.