Bilateral total knee replacement under a single anaesthetic, using a cementless implant is not unsafe.

Bilateral knee replacement under single anaesthetic is not a common procedure. There is a general agreement that this is associated with greater morbidity and mortality. However, there is a suggestion in literature that using a cementless implant could reduce this risk. We wanted to make a prospective comparison of safety and clinical results, between unilateral and bilateral cementless knee replacements performed under a single anaesthetic. A prospective non-randomised matched cohort study on 87 consecutive patients who had bilateral simultaneous/sequential knee replacement and 174 consecutive patients who had unilateral knee replacement between the period of 1997 and 2002 were included in this study. All patients had a cementless mobile-bearing implant. All patients had an independent objective assessment at follow-up. There was no significant difference between the two groups in terms of age, sex, primary diagnosis (osteoarthritis or rheumatoid arthritis), co-morbidity, ASA grade, average range of motion and average American knee society score and post-operative surgical complications. There was one early death in the bilateral group, and three in the unilateral group. The clinical results of bilateral group were as good as the unilateral group. Our study showed that in terms of postoperative medical and surgical complications, bilateral simultaneous/sequential knee replacement using a cementless mobile-bearing implant is as safe as a unilateral knee replacement. With careful patient selection, bilateral knee replacement under a single anaesthetic would be a suitable option for patients who present with bilateral symptomatic arthritis of the knee.