Failure to Optimize Before Total Knee Arthroplasty: Which Modifiable Risk Factor is the Most Dangerous?

Abstract

Background: Complications after total knee arthroplasty (TKA) are devastating for patients, and surgeons are held accountable in alternative payment models. Optimization of modifiable risk factors has become a mainstay in the preoperative period. We sought to evaluate the consequence of failure to optimize key risk factors in a modern cohort of patients who underwent TKA.

Methods: The American College of Surgeons National Surgical Quality Improvement Program database was searched to identify patients who underwent TKA in 2017-2018. Patients were considered optimized if they had a body mass index <40kg/m², had albumin >3.5g/dL, were nonsmokers, and were nondiabetic. Patients were then grouped based on the previous 4 risk factors. Thirty-day readmission, infection, general complications, and mortality were analyzed and compared between the groups.

Results: Overall, 84,315 patients were included in the study. A total of 31.6% of patients were not considered optimized. Body mass index >40kg/m², albumin <3.5, smoking, and insulin-dependent diabetes were all found to be associated with postoperative infection, readmission, mortality, and complication in general (P < .05). When compared, the nonoptimized group was found to have significantly higher risk of readmission (5 vs 3%), infection (2 vs 1%), general complications (8 vs 5%), and mortality (0.35 vs 0.1%) (all P < .001). Logistic regression showed that those with albumin less than 3.5g/dL had 3.7-fold higher odds of infection and 7.2-fold higher odds of 30-day mortality.

Conclusion: Despite knowledge that modifiable risk factors significantly influence postoperative outcomes, surgeons continue to operate on patients who are not optimized. Among the modifiable risk factors analyzed, hypoalbuminemia appears to be the strongest risk factor for all complications evaluated. Special attention should be paid to preoperative nutritional optimization.

Level of evidence: Retrospective cohort study, level IV.

Keywords: albumin; arthroplasty; complications; knee; optimization.