Incidence of embolic events during acetabular prosthesis insertion in total hip arthroplasty, and effect of intramedullary decompression in preventing embolism: higher risk of embolism with one-piece type prosthesis.

PURPOSE

In total hip arthroplasty (THA), there is a high risk of bone marrow embolism during femoral prosthesis insertion. However, the incidence during acetabular prosthesis insertion has received less attention. The first goal of this study was to determine the incidence of bone marrow embolism associated with acetabular prosthesis insertion. The second goal was to evaluate the effects of intramedullary decompression of the acetabulum in suppressing bone marrow embolism.

METHODS

To achieve the first goal, we evaluated the effects of prosthesis insertion on the incidence of bone marrow embolism, and on respiratory and cardiovascular dynamics. For the evaluation of bone marrow embolism, images obtained by transesophageal echocardiography were rated using Pitto's classification. To achieve the second goal, patients undergoing THA with a one-piece type acetabular prosthesis were divided into a control group and an acetabulum-decompression group, and the effects of insertion were analyzed in the same fashion.

RESULTS

In the 150 patients in the study, bone marrow embolism was rated as grade 0 in 9, grade 1 in 46, grade 2 in 61, and grade 3 in 34 patients. Patients rated as grade 2 and 3 exhibited significant reductions in blood pressure and Pa(O) (2) 5 min after acetabular prosthesis insertion. The results of multivariate analysis suggested that the incidence of bone marrow embolism was higher for the one-piece type prosthesis than for the two-piece type. Among the 60 patients who underwent THA with a one-piece type prosthesis, the incidence of bone marrow embolism was significantly lower in the decompression group.

CONCLUSION

As there are increasing indications for one-piece type acetabular prostheses in Japan, we must pay attention to the possibility of bone marrow embolism, not only during femoral prosthesis insertion but also during acetabular prosthesis insertion.