Longer Hospital Length of Stay After Total Knee Arthroplasty is an Independent Risk Factor for Increased Complication Rates

Longer Hospital Length of Stay After Total Knee Arthroplasty is an Independent Risk Factor for Increased Complication Rates

Logan Finger, MD, UNITED STATES Kelly A Murphy, BS, UNITED STATES Kenneth Urish, MD, PhD Michael O'Malley, MD, UNITED STATES Brian Klatt, MD, UNITED STATES Johannes F. Plate, MD, PhD, UNITED STATES

University of Pittsburgh, pittsburgh, PA, UNITED STATES


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Summary: When controlling for sex, age, race, ethnicity and Elixhauser Comorbidity Index Score, increased LOS after TKA is associated with greater odds of complications, readmissions, and revisions.


Introduction

Hospital length of stay (LOS) following total knee arthroplasty (TKA) continues to decrease due to enhanced recovery pathways and patient selection. However, despite improved patient pre-optimization and education, there remain patients that require longer LOS. While increased LOS following TKA may be function of patient selection, it remains unclear if postoperative complications rates and patient-reported outcomes (PROMS) are related to LOS. The purpose of this study was to evaluate the influence of LOS on complication rates and PROMS following TKA patients to allow for appropriate hospital resource allocation during hospital recovery.

Methods

All patients who underwent TKA at a large healthcare system between 2015-2024 were identified and included in this study. Patients were separated based on length of hospital stay after surgery: same calendar day discharge (SDD; n=2,327), discharge within 1 day (1DD; n=9,680), discharge after 2-4 days (2-4DD; n=15,586), and discharge after 5 or more days (5DD; n=900). Data collection included demographic data, complications, revisions, and additional clinical outcome data. Statistical analysis was performed using Chi-square test of independence, one-way ANOVA, and multiple logistic and linear regression analysis.

Results

A total of 28,493 patients were included in the analysis. Between 2016-2024, the mean LOS decreased from 2.75 days to 1.26 days. Overall, 5DD patients had 6.693 times higher odds of having a NQF 1550 complication (acute myocardial infarction, pneumonia, sepsis, surgical site bleeding, pulmonary embolism, death, mechanical complications, periprosthetic infection, wound infection) compared to SDD patients (p<0.01). SDD patients had the lowest readmission rate (0.258%), with 1DD having 2.48 (p=0.03), 2-4DD 3.72 (p<0.01) and 5+DD 7.94 (p<0.01) greater odds of readmission within 7 days. SDD patients also had the lowest revision rates (0.258%), with 1DD having 3.49 (p<0.01), 2-4DD 4.27 (p<0.01) and 5+DD having 4.82 (p<0.01) greater odds of requiring revision surgery. KOOS scores, on average, were 2.34 points higher in 1DD patients (p<0.01) and 1.58 points higher in 2-4DD patients compared with SDD patients (p=0.05). There was no significant difference in KOOS scores between 5DD and SDD patients. PROMIS10 Global Physical scores were mean 0.66 points higher in 1DD patients (p=0.03) and 0.73 points higher in 2-4DD patients than in SDD patients (p=0.02). There was no significant difference in PROMIS10 Global Physical scores between 5DD and SDD patients. PROMIS10 Global Mental Health Scores, surgical site infections, and in-house mortality rates were not associated with longer LOS.

Conclusions

When controlling for sex, age, race, ethnicity and Elixhauser Comorbidity Index Score, increased LOS after TKA is associated with greater odds of complications, readmissions, and revisions. While KOOS and PROMIS10 Global Physical scores were statistically different in some groups, these differences were clinically significant. Patients with shorter LOS had lower complication and revision rates while surgical site infection rates, mental health scores and in-house mortality were not associated with LOS. Patient preoptimization and education as well as in-hospital resources should be directed toward decreasing patient LOS as even patients with higher comorbidity classes may benefit from earlier discharge if medically and functionally possible.