Aim: To determine retrospectively the post-operative mortality and fatal pulmonary embolism (PE) rates in 936 consecutive primary total knee replacements (TKR) in the three month period after surgery where chemical thromboprophylaxis was not routinely used.

Methods: Operations were performed over a period of eleven years by eight different senior orthopaedic surgeons on 248 men and 525 women. One hundred and sixty three patients had bilateral TKRs and the mean age at the time of operation was similar (69.4 and 72.2 years respectively). Patients were traced by out-patient appointments, telephone and through their general practitioners (GPs). Post-mortem examinations were used to verify cause of death in all save three of the cases. All but one of the patients were followed up.

Results: There were no deaths from PE confirmed by post-mortem examinations. As three patients were certified dead without post-mortem examination and one patient could not be traced this meant that, at worst, our fatal PE rate was 0.43% (4/936; CI 0.14%–1.17%). The all-cause mortality rate was 0.64% (6/936; CI 0.26%–0.46%) (Table 1). The patient mortality was compared with the population mortality of England and Wales using standardised mortality ratios (SMRs). The SMR for both sexes combined was 0.74 (CI 0.29–1.52). We observed a lower mortality in females SMR = 0.67 and males SMR = 0.84 during the first three post-operative months than compared to the general population.

Conclusion: Fatal pulmonary embolism after total knee replacement without routine chemical thromboprophylaxis is uncommon. The overall death rate in this series of patients undergoing total knee replacement appears to be lower than that in the general population.