Purpose: To determine mortality and morbidity for bilateral total knee replacment compared to unilateral knee replacement and revision total knee replacement using the National National Hospital Discharge Survey to include large numbers of patients and look at outcomes.

Method: We analyzed nationally representative data to elucidate the demographics, comorbidities, hospital stay, in-hospital complications and mortality of patients undergoing BTKA and compared them with those of patients undergoing UTKA and revision TKA (RTKA). Data in the National Hospital Discharge Survey on hospital discharges with procedure codes for BTKA, UTKA and RTKA between 1990 and 2004 was analyzed. The demographics, comorbidities, in-hospital stay, complications and mortality were studied. We identified 4,169,489 discharges (153,259 BTKAs; 3,677,161 UTKAs; and 339,069 RTKAs).

Results: Patients undergoing BTKA were younger (1.5 years) and had a lower prevalence of comorbidities for hypertension (vs. UTKA), diabetes, lung disease, and coronary artery disease (vs. UTKA and RTKA). The length of hospitalization was 5.8 days for BTKA, 5.28 for UTKA, and 5.41 for RTKA. Despite similar length of hospitalization, the prevalence of procedure related complications was higher for BTKA (14.17%+/−0.76 (SE)) than for UTKA (9.01%+/−0.17) and RTKA (9.84%+/−0.57). In hospital mortality was highest for BTKA patients (BTKA: 0.47%+/−0.15%; UTKA: 0.30%+/−0.03; RTKA: 0.27%+/−0.09).

Conclusion: Despite younger age and lower comorbidity burden, patients undergoing BTKA had an approximately 1.6 times higher rate of procedure related complications and mortality compared to those undergoing UTKA. Outcomes for RTKA patients for most variables were similar to those for UTKA. In a multivariate analysis, BTKA, advanced age and male gender were independent risk factors for complications and mortality following TKA surgery.