Abstract
The purpose this prospective, randomized clinical trial was to determine if unilateral or bilateral simultaneous total hip arthroplasty procedures resulted in a differing incidence of fat embolization, degree of hemodynamic compromise, levels of hypoxemia or mental status changes. Also, the incidence of fat embolization was compared between the cemented and cementless total hip arthroplasty in the patients with a unilateral- and bilateral simultaneous total hip arthroplasty.
One hundred and fifty-six consecutive patients undergoing primary total hip arthroplasty were enrolled prospectively in the study after giving informed consent. The group consisted of fifty patients undergoing bilateral simultaneous total hip arthroplasty and 106 patients undergoing unilateral total hip arthroplasty. One hundred and three hips were cemented and 103 hips were cementless. To determine the hemodynamic changes and to detect the fat and bone marrow embolization, arterial and right atrial blood samples were obtained before implantation (baseline) and at one, three, five and ten minutes after implantation of the acetabular component. Also, arterial and right atrial blood samples were obtained at one, three, five and ten minutes after implantation of the femoral component. And then blood samples were obtained at twenty-four and forty-eight hours after the operation. Arterial blood pressure, right atrial pressure, arterial oxygen tension and carbon-dioxide tension were monitored at corresponding times. The presence of lipid was determined with oil red O fat stain and the presence of cellular contents of bone marrow was determined with Wright-Giemsa stain.
The incidence of fat embolism was not statistically different (P=1.000) between the patients with a bilateral total hip arthroplasty (twenty seven patients or 54 per cent) and the patients with a unilateral total hip arthroplasty (fifty-two patients or 49 per cent). In the semiquantitative analysis of fat globules in both groups, there was no tendency to have a higher number of fat globules in the bilateral group than in the unilateral group. Also, the incidence of bone marrow embolization was not statistically different (P=0.800) between the patients with a bilateral total hip arthroplasty (eight patients or 16 per cent) and the patients with a unilateral total hip arthroplasty (fourteen patients or 13 per cent). There was no statistical difference (P=0.800) in the incidence of the presence of fat globule between the cemented total hip (thirty-four patients or 34 per cent) and the cementless total hip arthroplasty (forty-seven patients or 44 per cent). Also, there was no statistical difference (P=0.627) in the incidence of the presence of bone marrow cells between the cemented total hip arthroplasty (thirteen patients or 13 per cent) and the cement-less total hip arthroplasty (twelve patients or 11 per cent). Four patients with positive bone marrow cells had neurological manifestation. All of these four patients developed diffuse encephalopathy with confusion and agitation for about twenty-four hours.
The present study confirmed that the incidence of fat and bone marrow embolization is similar in the patients with a bilateral simultaneous-and unilateral total hip arthroplasty as well as in the patients with cemented and cementless total hip arthroplasty. The patients with bone marrow cell emboli had a significantly lower arterial oxygen tension (p=0.022) and oxygen saturation (p=0.017) than the patients without bone marrow cell emboli. On the contrary, the number of fat globules did not affect the perioperative hemodynamic changes. Encephalopathy is related to the biochemical and/or mechanical changes by bone marrow cells.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
