What Factors Influence Operative Time in Total Knee Arthroplasty? A 10-Year Analysis in a National Sample

Changes in reimbursement in total knee arthroplasty (TKA) by Centers for Medicare and Medicaid Services (CMS) have been tied to a perceived decrease in the total surgical time required to perform these operations. However, little information is available to CMS about recorded surgical times for TKA across the United States and the variables that drive these values. Therefore, the purpose of our study, is to evaluate (1) changes in operative time over time and (2) factors associated with variations in operative time.

The National Surgical Quality Improvement Program database was queried to identify all primary TKAs conducted between January 1, 2008, and December 31, 2017. All TKAs conducted within our study period that had operative time data available were included. Multivariable linear models were created to assess factors that influence operative time over the study period.

Our final analysis included 140,890 TKAs. The mean operative time across the study period was found to be 92.60 minutes. Examining quarterly values, operative time stayed within 5 minutes of this mean (range, 89.80-97.51 minutes). Age, sex, functional status, anesthesia type, body mass index, operative year, transfusion requirements, and preoperative laboratory findings significantly influenced operative time (P < .05 for all).

Our analysis indicates that while there are numerous factors that influence procedure duration, operative times have remained stable. This information should be heavily considered in regard to physician reimbursement, because providers are maintaining operative times and work effort while mitigating factors that influence outcomes in the perioperative period.