Abstract
Aim
To investigate the incidence, types and trends in diagnosis of venous thromboembolic events (VTE) in patients undergoing total knee arthroplasty (TKA) over a ten-year period.
Methods
Data from 5100 consecutive TKAs performed in our unit between April 1996 and March 2006 were prospectively collected by the Scottish Arthroplasty Project (SAP). This database contains data on 100% of arthroplasty cases in Scotland. We retrospectively reviewed casenotes of these patients to identify thromboprophylaxis given, the diagnosis of VTE, treatment and adverse outcomes.
Results
The SAP data identified 123 (2.4%) patients as having been admitted with or died from a VTE episode. There were 2 (0.04%) deaths from pulmonary embolism (PE). Of the 123 VTEs identified, 55 had PE, 17 had above knee deep vein thrombosis (DVT), 28 had calf DVT and 14 had no evidence of VTE though were incorrectly coded as such in the database. Data were unavailable for 9 patients. Of the 28 patients with calf only DVT, 18 were given therapeutic anticoagulation: five developed haemorrhagic complications. The VTE rate fell steadily from 2.26% in 1996-7 to 1.05% in 2002-3 but increased to 1.8% from 2003-2006. This increase was due to PE diagnosed between days 1 and 5 post-surgery. This increase corresponds with the introduction of a more sensitive CT scanner and it is postulated that this increase may be due to detection of embolic debris from the time of surgery rather than post-operative thromboembolism.
Conclusions
Death due to PE is a very rare event following TKA. There was a decline in the rate of VTE over the first seven years of the study but an increase in early post-operative PE in the last 3 years. There is considerable overdiagnosis and treatment of calf DVT with significant resultant morbidity. PE is probably also overdiagnosed and overtreated.
