Epidemiology of Revision Total Knee Arthroplasty in the United States, 2012 to 2019.

Background: As primary total knee arthroplasty volume continues to increase, so will the number of revision total knee arthroplasty (rTKA) procedures. The purpose of this study is to provide an updated perspective on the incidence, indications, and financial burden of rTKA in the United States. Material and methods: This was a retrospective epidemiologic analysis using the National Inpatient Sample. International Classification of Diseases ninth and tenth revision codes were used to identify patients who underwent rTKA and create cohorts based on rTKA indications from 2012 to 2019. National and regional trends for length of stay, cost, and discharge location were evaluated. Results: A total of 505,160 rTKA procedures were identified. The annual number of rTKA procedures increased by 29.6% over the study period (56,490 to 73,205). The top 3 indications for rTKA were aseptic loosening (23.1%), periprosthetic joint infection (PJI) (20.4%), and instability (11.0%). Over the study period, the proportion of patients discharged to skilled nursing facility decreased from 31.7% to 24.1% (P < .001). Hospital length of stay decreased from 4.0 days in 2012 to 3.8 days in 2019 (P < .001). Hospital costs increased by $1300 from $25,730 to $27,077 (P < .001). The proportion of rTKA cases performed at urban academic centers increased (52.1% to 74.3%, P < .001) while that at urban nonacademic centers decreased (39.0% to 19.2%, P < .001). Conclusion: The top 3 indications for rTKA were aseptic loosening, PJI, and instability, with PJI becoming the most common indication in 2019. These cases are increasingly being performed at urban academic centers and away from urban nonacademic centers. Level of Evidence: 3 (Retrospective cohort study).

Instability Is the Most Common Indication for Revision Hip Arthroplasty in the United States: National Trends From 2012 to 2018.

BACKGROUND: As primary total hip arthroplasty volume continues to increase, so will the number of revision total hip arthroplasty (rTHA) procedures. These complex cases represent a significant clinical and financial burden to the health-care system. METHODS: This was a retrospective review using the National Inpatient Sample. International Classification of Diseases, 9th and 10th revision codes were used to identify patients who underwent rTHA and create cohorts based on rTHA indications from 2012 to 2018. National and regional trends for length of stay (LOS), cost, and discharge location were evaluated. RESULTS: A total of 292,250 rTHA procedures were identified. The annual number of rTHA procedures increased by 28.1% from 2012 to 2018 (37,325 to 47,810). The top 3 indications for rTHA were instability (20.4%), aseptic loosening (17.8%), and infection (11.1%). Over the study period, the proportion of patients discharged to skilled nursing facility decreased from 44.2% to 38% (P < .001). Hospital LOS decreased on average from 4.8 to 4.4 days (P < .001). Infections had the highest average LOS (7.3 days) followed by periprosthetic fractures (6.5 days). Hospital costs decreased over the study period, from $25,794 to $24,555 (P < .001). The proportion of rTHA cases performed at urban academic centers increased (58.0% to 75.3%, P < .001) while the proportion performed at urban nonacademic centers decreased (35.5% to 19.4%, P < .001). CONCLUSION: Instability was the most common indication for rTHA between 2012 and 2018. The proportion of rTHA performed in urban academic centers has increased substantially, away from urban nonacademic centers. While cost and LOS have decreased, significant geographic variability exists.

Recall Rates of Total Knee Arthroplasty Devices Are Dependent on the FDA Approval Process.

Introduction The medical device industry has grown substantially in recent years. There is limited research examining orthopedic subspecialties and the recall of orthopedic devices. We hypothesize that knee arthroplasty devices cleared through the Food and Drug Administration (FDA) 510(k)-notification process would have a higher recall rate than the premarket approval (PMA) process. Methods The FDA database was thoroughly queried for all knee arthroplasty surgical devices from January 1, 2007 through December 31, 2017. Recalled devices were analyzed by manufacturer, type of implant, recall class, manufacturer-determined reason, FDA-determined reason, quantity affected, submission type, and distribution within the United States or internationally. Results Out of over 30,000 medical devices on the market, a total of 300 knee arthroplasty devices from 18 different companies were recalled during the time frame of this study. Tibial components accounted for 35.33% of devices, polyethylene implants for 38.67%, and femoral components for 15%. The most common reason for recall was device design (n = 134, 44.67%), followed by process control (n = 32, 10.67%). Of the 300 knee arthroplasty devices recalled, 267 (89.0%) were cleared through the 510(k) premarket notification process and 33 (11.0%) devices were approved through the PMA process. Conclusions A larger proportion of knee arthroplasty surgical devices cleared through the 510(k) process were recalled compared to implants approved through the stricter PMA process. Changing the 510(k) process may enable manufacturers to improve upon the safety of their devices.

Patient demographics and cardiovascular risk factors differentially influence geometric remodeling of the aorta compared with the peripheral arteries.

BACKGROUND: Detailed knowledge of the dimensions and shape of the main arteries of the body and how they change with age and disease is important for understanding arterial pathophysiology and improving minimally invasive devices to treat arterial diseases. Our goal was to describe and compare geometric remodeling of the aorta and peripheral arteries in the context of patient demographics and cardiovascular risk factors. METHODS: Three-dimensional reconstructions of computed tomography angiography scans were performed in 122 subjects 5-93 years of age (mean 47 ± 24 years, 64 M/58 F). Best-fit arterial diameters, lengths, and tortuosity for the principle named arteries in the chest, abdomen, pelvis, and upper thigh were measured, and multiple linear regression analysis was performed to examine how these morphologic parameters associate with patient demographics and risk factors. RESULTS: Large elastic arteries increased their diameter, length, and tortuosity with age, whereas muscular arteries primarily became more tortuous. Demographics and risk factors explained >70% of the variation in diameters of the abdominal aorta, paravisceral aorta, and the aortic arch; and >75% of variation in tortuosity from the profunda femoris to the brachiocephalic artery. Male sex, larger body mass index, and hypertension contributed to larger diameters, whereas the presence of diabetes was associated with somewhat-straighter arteries. Overall, the effects of cardiovascular risk factors on geometric remodeling were small compared with those of demographics. CONCLUSION: The geometry of the vascular tree is greatly affected by aging, demographics, and some risk factors. Elastic and muscular arteries remodel differently, possibly as the result of differences in their microstructure.