In the December 6, 2017 issue of The Journal, Arshi et al. report on a detailed analysis of a large administrative database, looking specifically at one-year complications associated with outpatient versus standard inpatient knee replacement. This type of analysis is crucial because of the rapidly growing interest in outpatient joint replacement among patients, payers, and the orthopaedic community.
The data convince me that these outpatient procedures should proceed, but with a little more caution. Although the absolute complication rates in both surgical settings were very low, after adjusting for age, sex, and comorbidities, the authors found a higher relative risk of several surgical and medical complications among outpatients—including component failure, infection, knee stiffness requiring manipulation under anesthesia, and deep vein thrombosis.
One important element that is lacking in this analysis is adjustment for surgeon/hospital volume. We know from important work by Katz and others that patients managed at centers and by surgeons with greater volumes of total knee replacement have lower risks of perioperative adverse events.
These results from Arshi et al. are definitely not a call to stop the expansion of outpatient joint replacement protocols. Instead, I think this study should prompt every joint-replacement center to analyze its risk-adjusted inpatient and outpatient outcomes—and to ensure, as these authors emphasize, that outpatients receive the same level of attention to rehabilitation, antibiotic administration, and thromboprophylaxis as inpatients.
Enhancing outpatient knee-replacement protocols will serve local communities well, and the nationwide orthopaedic community will receive further confirmation that outpatient joint replacement is a move in the right direction.
Marc Swiontkowski, MD