Patients aged 80 and above face higher critical systemic complication rates after single-stage bilateral versus...

Single-stage bilateral total knee arthroplasty (SB-TKA) offers several benefits for patients with bilateral knee diseases, including reduced cumulative hospitalisation periods and costs. However, it is associated with increased mortality and postoperative complications. Patient selection criteria to minimise these risks remain unclear. This study aimed to identify age groups with increased risk of critical systemic complications after SB-TKA compared with unilateral TKA (U-TKA) using a nationwide database.

Data from inpatients undergoing TKA between 2010 and 2022 were obtained from the Diagnosis Procedure Combination database. The primary outcome was a composite of in-hospital death and systemic complications requiring additional procedures or interventions following TKA. To compare outcomes between the SB-TKA and U-TKA groups, stabilised inverse probability of treatment weighting (IPTW) using propensity scores was applied to balance baseline covariates. Subgroup analyses were conducted based on age categories (≤69, 70-79, and ≥80 years).

During the study period, 25,161 SB-TKA patients and 317,037 U-TKA patients were identified. Stabilised IPTW analysis showed that the composite outcome during hospitalisation occurred more frequently after SB-TKA than after U-TKA (0.65 % vs. 0.44 %; risk ratio, 1.47; 95 % confidence interval, 1.21-1.78). Subgroup analysis revealed a significantly higher risk of the composite outcome in the SB-TKA group among patients aged ≥80 years (1.02 % vs. 0.59 %; risk ratio, 1.72; 95 % confidence interval, 1.28-2.31), while no significant differences were observed in patients aged ≤69 or 70-79 years.

SB-TKA is associated with higher risk of critical systemic complications compared with U-TKA in patients aged ≥80 years.

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