Aim: To identify the local and systemic morbidity of simultaneous sequential bilateral total knee arthroplasty in a large patient population and to undertake a comparative statistical analysis with a group of matched patients who underwent staged bilateral total knee replacement during the same period.

Methods: Theatre records at two regional district general hospitals were scrutinised to identify all patients who had undergone simultaneous sequential and staged bilateral total knee arthroplasty over a three year period. Patient case notes and hospital charts were retrospectively reviewed to obtain several outcome measures to allow subsequent risk factor assessment.

Results: 134 patients with 268 primary knee arthroplasties undergoing a simultaneous procedure were identified. The average age was 70 with a minimum follow up of 12 months. The study results revealed 1.5% mortality, 5.2% local complication and 14.9% systemic complication rates and this increased with age. During the same period 34 patients (68 knees) who had undergone staged procedures at least 3 months apart were also identified. Statistically significant findings between both groups included the reduced length of hospital stay, a 3-fold increase in the requirement for banked blood (particularly when either suction drainage or low molecular weight heparin thromboprophylaxis was used) and a higher degree of intra operative instability in those undergoing simultaneous bilateral total knee replacement.

Conclusions: Patients can continue to enjoy the benefits of simultaneous bilateral knee arthroplasty, however, extreme caution must be taken in selection of patients over 75 years, high dependency facilities must be available and an acceptable alternative to banked blood transfusion needs to be used.