EMBOLIC COMPLICATIONS OF CALF THROMBOSIS FOLLOWING TOTAL HIP-ARTHROPLASTY

The incidence of clinically significant pulmonary embolism following t otal hip arthroplasty is reported in patients with venographically doc umented deep venous thrombosis. One hundred seventy-four patients who enrolled in a prospective evaluation of deep venous thrombosis prophyl axis underwent contrast venography 7-10 days after operation. Ten pati ents with proximal and 12 patients with isolated deep calf thrombosis were identified on routine venogram reading and received appropriate a nticoagulant therapy, including a 6-12-week course of warfarin. There were no clinically evident embolic events and no bleeding complication s in this group. A secondary blinded review of venograms several weeks later identified isolated deep calf thrombi in 13 other patients, non e of whom had received warfarin after discharge. Four of the 13 patien ts (P < .02) subsequently presented with pulmonary embolism at a mean of 33.5 days after operation. Asymptomatic deep calf venous thrombosis following total hip arthroplasty is associated with a significant ris k of developing clinically evident pulmonary embolism within the first 8 weeks after operation. Once identified, these thrombi were effectiv ely managed with outpatient warfarin anticoagulation, and both embolic and bleeding complications were avoided. This study documents the nee d for more prolonged routine prophylaxis against venous thrombosis tha n has heretofore been the rule, extending beyond the time of discharge from the hospital. Alternatively, the authors' experience supports th e use of routine screening venography following total hip arthroplasty to allow detection and selective anticoagulant treatment of deep veno us thrombosis in both the thigh and calf.