JOA - 2026-08-08 - Journal Article
More Technology, but Similar Early Safety: Robotic Versus Conventional Unicompartmental Knee Arthroplasty, a 30-Day Outcome National Database Study.
Sribhashyam S, Gooch BR, Yazdanpanah S, Setliff JC, Cassidy BP, Reiter CR, O'Neill CN, Satpathy J, Satalich JR
Topics
Key Takeaway
After propensity matching, robotic UKA produced longer operative times (86.1 vs 78.9 min) and shorter hospital stays (0.4 vs 0.6 days) but no significant difference in 30-day adverse events (3.4% vs 2.1%) compared to conventional UKA.
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Summary
This study used NSQIP (2022–2024) to compare 30-day adverse events between robotic and conventional UKA using CPT 27446 and the dedicated NSQIP robot-use variable, with 1:2 propensity matching achieving all SMDs <0.1. R-UKA had longer operative times and higher outpatient rates (92.2% vs 80.9%) but no significant differences in any adverse event category (major, minor, or infectious complications). COPD was the sole significant predictor of adverse events in R-UKA patients (OR 9.442).
Key Limitation
The 30-day follow-up window cannot capture the outcomes most relevant to robotic UKA's purported benefit—component positioning accuracy, alignment, and mid- to long-term survivorship.
Original Abstract
INTRODUCTION
Robotic assistance in unicompartmental knee arthroplasty (UKA) has been increasingly adopted, but evidence regarding early safety remains constrained by heterogeneities and limitations such as Current Procedural Terminology (CPT) code layering designs, smaller sample sizes, and baseline imbalances. Accordingly, this study compares short-term (30-day) adverse events and outcomes between robotic UKA (R-UKA) and conventional UKA (C-UKA) using a propensity-matched, uniformly-defined cohort.
METHODS
A national database (2022-2024) was queried for patients undergoing UKA using CPT 27446. R-UKA and C-UKA were distinguished using the dedicated National Surgical Quality Improvement Program (NSQIP) "robot use" variable. Cases with missing key entries or complexity-amplifying add-ons were excluded. Propensity score matching (1:2) balanced baseline covariates (all standardized mean differences less than 0.1), yielding 727 R-UKA and 1,454 C-UKA matched cases. The primary outcome was any 30-day postoperative adverse event (AAE), supplemented by secondary complication-stratifying analyses. Statistics included independent t-tests, Chi-squares, and exploratory multivariable regressions with odds ratios.
RESULTS
The R-UKAs were associated with longer operative times (86.1 ± 34.7 versus 78.9 ± 35.5 minutes; P < 0.001), shorter lengths of stay (0.4 ± 0.8 versus 0.6 ± 1.1 days; P < 0.001), and were more often performed outpatient (92.2 versus 80.9%; P < 0.001). The rates of AAEs were similar between R-UKA and C-UKA procedures (3.4 versus 2.1%, respectively), as were rates of major (1.7 versus 0.9%), minor (2.1 versus 1.4%), and infectious (2.6 versus 1.5%) complication subgroupings (all P > 0.05). Chronic obstructive pulmonary disease was the sole significant predictor of AAE, observed only in the R-UKA cohort (odds ratio = 9.442; P = 0.002).
CONCLUSION
Using standardized identification and propensity matching, R-UKA was associated with longer operative times and shorter stays compared with C-UKA, though without any clear or consistent reductions in 30-day adverse events. Future, longitudinal research is needed to corroborate findings.