Monitoring of 140 patients after hip-replacement arthroplasty using both
impedance plethysmography and 125I fibrinogen scanning of the lower
extremities showed that half had no evidence of thrombosis, one-quarter had
moderate or extensive thrombosis, and one-quarter had abnormal scans only.
In the patients with only abnormal scans the process appeared to resolve
spontaneously. The findings by impedance plethysmography therefore appeared
to differentiate non-invasively between thromboses that would and would not
resolve, and it is suggested that for some patients a monitoring regimen
may be preferable to routine prophylaxis.