Utilization of Autologous Chondrocyte Implantation in the Knee Is Increasing While Reoperation Rates Are Decreasing Despite Increasing Preoperative Comorbidities

Abstract

Purpose: The primary purpose of this study was to assess the use of autologous chondrocyte implantation (ACI) procedures in the knee during last decade, and the secondary aims of the study were to determine reoperation rates after ACI and to identify associated risk factors.

Methods: A retrospective cohort study from 2010-2020 was performed using the PearlDiver database. The database was queried for the Current Procedural Terminology (CPT) code for ACI performed in any knee location, including the patellofemoral and tibiofemoral joints. Reoperation was defined as interventional knee procedures or total knee arthroplasty after ACI. Reoperations were identified using CPT and International Classification of Diseases codes. Univariate and multivariate logistic regression were used to identify risk factors for reoperation. Significance was defined as P < .05.

Results: Among the 2010 patients included in this study, there were 90-day and overall reoperation rates of 2.24% and 30.4%, respectively, with an average follow up of 4.8 ± 3.3 years. The most common reoperations included chondroplasty, meniscectomy, and microfracture. There was an increased rate of ACI performed from 2017-2019 (5.53/100,000) compared to 2014-2016 (4.16/100,000; P < .001). ACI surgeries performed in 2017-2019 were associated with decreased risk of reoperation within 2 years relative to 2014-2016 (odds ratio [OR] = 0.70; 95% confidence interval [CI], 0.52-0.94; P = .019). In the entire ACI cohort, older age (OR = 1.07; 95% CI, 1.05-1.09; P < .001) and tobacco use (OR = 2.13; 95% CI, 1.06-3.94; P = .022) were associated with increased risk of conversion to arthroplasty. Male sex was associated with decreased overall reoperation rates (OR = 0.73; 95% CI, 0.60-0.89; P = .002).

Conclusions: There has been increasing use of ACI in the knee with decreased risk of reoperation since 2017 and the introduction of matrix-associated autologous chondrocyte implantation. Older age and tobacco use were predictors of increased risk of conversion to arthroplasty. Male sex was associated with decreased risk of reoperation.

Level of evidence: Level IV, retrospective cohort design; database study.