The relative safety of one-stage bilateral total knee arthroplasty.

Patients with osteoarthritis of the knee often require bilateral knee replacement before fulfilling their full ambulatory potential. Despite extensive research there is considerable debate about the risks of performing simultaneous bilateral knee replacements under the same anaesthetic. Our aim was to compare the relative short-term morbidity of one-stage bilateral with unilateral total knee arthroplasty in a retrospective, consecutive cohort of patients. Seventy-two bilateral knee replacements were case-matched for age and gender with 144 unilateral knees. One-stage bilateral arthroplasty was associated with increased morbidity with respect to wound (6.0 vs 0.7%; p = 0.003) and deep prosthetic (3.5% vs 0.7 %; p = 0.02) infections, cardiac complications (3.5% vs 0.7%; p = 0.04) and chest infections (7.0% vs 1.4%; p = 0.04). No differences were observed in the mortality rates (p = 0.30) and risk of thrombo-embolism (p = 0.70). We conclude that one-stage bilateral total knee arthroplasty is associated with increased morbidity compared with unilateral knee replacement.