Procedure length is independently associated with overnight hospital stay and 30-day readmission following anterior cruciate ligament reconstruction

The purpose was to characterize the independent effect of procedure length on the rates of 30-day perioperative complications, hospital readmissions, and overnight hospital stay in patients undergoing arthroscopic anterior cruciate ligament reconstruction (ACLR). We hypothesized that longer procedure length in primary ACLR increases the risk for post-operative complications. Primary ACLR cases from 2005 to 2015 were identified in the American College of Surgeons National Surgical Quality Improvement Program registry. Patients were categorized into two cohorts based on procedure length, either less than or greater than 90 min. Two equal-sized propensity-matched cohorts were generated to account for differences in baseline and operative characteristics. Thirty-day clinical outcomes were compared using bivariate analyses between propensity-matched groups that controlled for patient-specific factors and concurrent meniscal repair. Multivariate logistic regression models were used to identify independent predictors of hospital readmission and overnight hospital stay. In total, 12,077 ACLR cases were identified. The rate of any 30-day complication was increased in longer procedures relative to shorter procedures (1.6% vs 0.9%, p = 0.006), as were the rates of returning to the operating room (0.6% vs 0.3%, p = 0.03), hospital readmission (1.0% vs 0.3%, p = 0.001), and overnight hospital stay (16.2% vs 6.0%, p < 0.001). Obesity was a risk factor for both hospital readmission and overnight hospital stay, while hypertension, diabetes, chronic obstructive pulmonary disease, and a smoking history were associated with increased rates of overnight hospital stay. The most common reasons for hospital readmission were deep vein thrombosis or pulmonary embolism (25.0% of all readmitted patients), surgical site infection (25.0%), and post-operative pain (14.1%). In this propensity-matched analysis adjusting for baseline patient characteristics and operative factors, procedure length of greater than or equal to 90 min in ACLR was independently associated with an increased risk of hospital readmission and overnight hospital stay. As a surrogate measure of surgical complexity, operative time may be a useful perioperative variable for post-operative risk stratification and patient counseling. III