BACKGROUNDDuring the process of bone cement joint replacement, some patients show a series of complications, such as a sudden drop in blood pressure or dyspnea. The cause of the complication is considered to be due to emboli caused by the femur prosthesis insertion. The purpose of the present study was to detect the pulmonary embolism in rabbits after bone cement perfusion by radioimmunoimaging, and to explore its protective measures.

METHODSForty rabbits, 2.5 - 3.0 kg weight, were randomly assigned to four groups, with ten rabbits in each group. Group I (no intervention): Bone cement perfusion was done after medullary cavity reaming and pressurizing. Group II (epinephrine hydrochloride intervention): The medullary cavity was rinsed with a 1:10 000 normal saline-diluted epinephrine hydrochloride solution followed by bone cement perfusion after medullary cavity reaming and pressurizing. Group III (fibrin sealant intervention): The medullary cavity was precoated with fibrin sealant followed by bone cement perfusion after medullary cavity reaming and pressurizing. Group IV (blank control group): The medullary cavity was not perfused with bone cement after reaming. In each group, the rabbits underwent femoral head resection and medullary cavity reaming. Before bone cement perfusion, 2 ml of developing tracer was injected through the ear vein. Radionuclide imaging was performed at 60, 120, and 180 minutes after bone cement perfusion, and the pulmonary radioactivity in vivo was measured. The rabbits were immediately sacrificed, and the pulmonary tissue was removed and its radioactivity was measured in vitro. Pulmonary tissue was then fixed and the pulmonary embolism and the associated pathological changes were observed.

RESULTSThe pulmonary radioactivity in vivo was measured at 60, 120, and 180 minutes after bone cement perfusion. The radioactivities of the four groups were 11.67 ± 2.16, 14.59 ± 2.92 and 18.43 ± 4.83 in group I; 8.37 ± 3.05, 10.35 ± 2.24 and 11.48 ± 2.96 in group II; 3.91 ± 1.19, 5.53 ± 2.95 and 7.25 ± 1.26 in group III; 1.04 ± 0.35, 1.14 ± 0.87 and 1.43 ± 0.97 in group IV. The radioactivities of groups I, II, III at 60, 120 and 180 minutes were significantly higher than group IV (P < 0.05). The pulmonary embolism could be detected. Pretreatment with epinephrine hydrochloride and fibrin sealant significantly decreased the pulmonary radioactivity in group II and group III, but it was still higher than in the group IV.

CONCLUSIONSRadioimmunoimaging is an alternative method for the dynamic observation of rabbit pulmonary embolism after bone cement perfusion. Radioimmunoimaging is the optional way to evaluate the effect of pretreatment with epinephrine hydrochloride or fibrin sealant on pulmonary embolism after bone cement perfusion.