History of total knee arthroplasty is associated with increased risk of revision following subsequent lumbar fusion.

Abstract

The prevalence of degenerative knee and lumbar spine pathologies has been rising given the aging population. It is increasingly common for patients to undergo both total knee arthroplasty (TKA) and lumbar fusion (LF). The purpose of this study is to determine whether there is a disparate risk of and time to revision lumbar fusion (rLF) in patients with a history of TKA. We retrospectively queried the national <i>Premier Healthcare Database</i> ® for individuals who received a LF from 2016 to 2022. Patients with a history of TKA prior to their lumbar fusion were noted (TKA + LF). Patient characteristics were compared using chi-squared for categorical variables and t-tests for continuous variables. Multivariate logistic regression was used to determine odds of rLF using these covariates: age, gender, race, inpatient/outpatient status, primary lumbar fusion diagnosis, obesity status, osteoporosis status, and Elixhauser comorbidity count. 1:1 propensity-score-matched Cox Proportional Hazards models and Kaplan-Meier curves were created to assess time-based risk for rLF. The TKA + LF cohort was composed of 11,696 patients (mean age = 69.2 years, male = 40.6%, white = 85.5%). The LF cohort was composed of 117,688 patients (mean age = 60.9 years, male = 46.6%, white = 83.1%). The TKA + LF cohort had a higher proportion of patients with obesity (34.7% vs. 23.0%, p < 0.001) and osteoporosis (8.1% vs. 4.4%, p < 0.001). The TKA + LF cohort had a higher rate of rLF (10.8% vs. 6.5%, p < 0.001). There was no difference in time to revision between cohorts (512.18 ± 455.86 vs. 499.05 ± 470.45 days, p = 0.356). Multivariate logistic regression found increased odds of rLF in the TKA + LF cohort (OR = 1.695, 95% CI = 1.588-1.809, p < 0.001), and propensity-matched Cox models (n = 11,696 patients) found a higher time-based risk for rLF in the TKA + LF cohort (HR = 1.685, 95% CI = 1.541-1.844, p < 0.001). This study demonstrates increased odds and time-based risk for rLF in the TKA + LF cohort. Future research is needed to clarify the mechanisms driving this association between TKA history and rLF. These results highlight a need for comprehensive treatment of knee and spine pathology to achieve maximal outcomes.