# Clinical safety and efficacy of simultaneous bilateral total knee arthroplasty in an Asian population: a propensity score-matched analysis

## TL;DR

The study finds that simultaneous bilateral knee replacement is as safe as single knee surgery in Asian patients, despite higher blood loss and transfusion rates.

## Contribution

This is the first propensity score-matched analysis of BTKA safety and efficacy in an Asian population.

## Key findings

- BTKA and UTKA had similar 30-day complication and ICU admission rates.
- BTKA resulted in longer hospital stays, more transfusions, and greater blood loss.
- Patient-reported outcomes were comparable at one year post-surgery.

## Abstract

Clear clinical guidelines on performing simultaneous bilateral total knee arthroplasty (BTKA) are lacking. We compare the clinical outcomes between BTKA and unilateral total knee arthroplasty (UTKA) using propensity score matching to assess safety and clinical efficacy, hypothesizing no difference in clinical safety.

Among 1,665 BTKA and UTKA cases, patients were matched in a 1:1 ratio by age, sex, body mass index, follow-up, and comorbidities, resulting in 653 patients per group. Primary outcomes included 30-day complication rates and intensive care unit (ICU) admission rates. Secondary outcomes included length of stay (LOS), transfusion rate, estimated blood loss, hemoglobin (Hb) levels (preoperative and two days postoperative), Hb decrease, and 1-year mortality rate. The patient-reported outcomes (PROMs) was measured preoperatively and at 3, 6, and 12 months postoperatively using the American Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index, and EuroQol 5-Dimension.

There were no differences in the 30-day complication rates and ICU admission rate between the BTKA and UTKA groups after matching (1.4% vs. 0.9%; p = 0.60, 0.5% vs. 0.6%; p = 1.00). However, patients who underwent BTKA had a longer LOS, a higher incidence of transfusion (7.2% vs. 2.1%; p < 0.001), greater blood loss (128.6 ± 75.5 vs. 72.5 ± 45.6 mL; p < 0.001), and a more pronounced decrease in Hb levels (3.1 vs. 2.9 g/dL; p < 0.001) than those who underwent UTKA. No significant differences were observed in PROMs at one year postoperatively.

Patients who underwent BTKA reported similar 30-day complication rates, ICU admissions, and PROMs compared to UTKA. Despite higher LOS, transfusion rates, blood loss, and Hb decrease, BTKA remains a safe, effective option. It should be performed cautiously, considering patient comorbidities and overall health in treating bilateral knee OA.

The online version contains supplementary material available at 10.1186/s13018-025-05933-7.