The BTK Safety Score: A Novel Scoring System for Risk Stratifying Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty

Abstract

Selection of appropriate candidates for simultaneous bilateral total knee arthroplasty (si-BTKA) is crucial for minimizing postoperative complications. The aim of this study was to develop a scoring system for identifying patients who may be appropriate for si-BTKA. Patients who underwent si-BTKA were identified in the National Surgical Quality Improvement Program database. Patients who experienced a major 30-day complication were identified as high-risk patients for si-BTKA who potentially would have benefitted from staged bilateral total knee arthroplasty. Major complications included deep wound infection, pneumonia, renal insufficiency or failure, cerebrovascular accident, cardiac arrest, myocardial infarction, pulmonary embolism, sepsis, or death. The predictive model was trained using randomly split 70% of the dataset and validated on the remaining 30%. The scoring system was compared against the American Society of Anesthesiologists (ASA) score, the Charlson Comorbidity Index (CCI), and legacy risk-stratification measures, using area under the curve (AUC) statistic. Total 4,630 patients undergoing si-BTKA were included in our cohort. In our model, patients are assigned points based on the following risk factors: +1 for age ≥ 75, +2 for age ≥ 82, +1 for body mass index (BMI) ≥ 34, +2 for BMI ≥ 42, +1 for hypertension requiring medication, +1 for pulmonary disease (chronic obstructive pulmonary disease or dyspnea), and +3 for end-stage renal disease. The scoring system exhibited an AUC of 0.816, which was significantly higher than the AUC of ASA (0.545; p < 0.001) and CCI (0.599; p < 0.001). The BTK Safety Score developed and validated in our study can be used by surgeons and perioperative teams to risk stratify patients undergoing si-BTKA. Future work is needed to assess this scoring system's ability to predict long-term functional outcomes.

The impact of Charlson Comorbidity Index on surgical complications and reoperations following simultaneous bilateral total knee arthroplasty

“…In our study, the rates of 30-day and 90-day readmission were 2.11% and 2.88%, respectively. These rates were slightly lower than recent large-scale studies 23,24 . Hart et al included 1771 patients who underwent simultaneous bilateral TKA procedure and the 30-day readmission rate was 3.6% 23 .…”

“…The slightly lower readmission rate observed in our cohort (Taiwanese, Asian cohort) could be attributed to the lower incidence of symptomatic VTE. Symptomatic VTE events accounted for only 3% of the complications in our cohort, but for 38% and 60% of the complications recorded by Hart et al and Wang et al, respectively 23,24 . The 1-year reoperation rate (1.41%) in our study was low and consistent with the rates (1.2-1.48%) in two large-scale studies reported by Bolognesi et al and Bini et al 17,25 Notably, infection (including SSC and PJI) and trauma events (including fracture and tendon rupture) accounted for 86.4% of the reasons for early reoperation in our study.…”

“…Wang et al reviewed 4613 patients who received simultaneous bilateral TKA procedures as reported in the National Surgical Improvement Program database. The postoperative 30-day major complication rate was 2.59% 24 . The slightly lower readmission rate observed in our cohort (Taiwanese, Asian cohort) could be attributed to the lower incidence of symptomatic VTE.…”