Abstract
Many studies have compared outcomes in total knee arthroplasty (TKA) versus unicompartmental
knee arthroplasty (UKA); however, to the authors' knowledge, there is no study evaluating
complication rates in patients with significant comorbidities. The purpose of this
retrospective study was to compare the incidence of postoperative complications, readmission
and reoperation rates, length of stay (LOS), and discharge location for patients with
significant medical comorbidities undergoing TKA versus UKA. Using the NSQIP database
from 2008 to 2018, patients were identified by CPT code (27447 or 27446) and admission
diagnostic code of primary osteoarthritis and included in the study if they had an
American Society of Anesthesia score greater than or equal to 3. Chi-square test was
used to compare categorical variables and t-test for continuous variables. Multivariate regression was used to compare outcomes
of interest between groups. A total of 167,054 patients were analyzed with 97.3% undergoing
TKA. TKA patients had a greater overall complication rate than those undergoing UKA
(p < 0.001). Readmission rates were approximately 1.5 times higher in TKA compared with
UKA (p = 0.002), while no statistically significant difference was discovered in reoperation
rates (p = 0.868). TKA was also associated with decreased rates of same day discharge, discharge
within 24 hours of surgery, and discharge home (p < 0.001, <0.001, and <0.001, respectively). This study found an increase in complication
rates, readmission rates, and LOS, along with a lower likelihood of discharge home
when undergoing a TKA. These findings suggest that patients with significant medical
comorbidities at baseline may benefit from UKA over TKA when anatomically indicated.
Keywords
unicompartmental knee arthroplasty - total knee arthroplasty - complication rates
