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).

Background

There is a new method of transportation that started in our community in late 2017- rideshare electric scooters (e-scooters). These scooters have proven immensely popular and can now be found in many cities around the world. Despite the pervasiveness of e-scooters, their associated injury patterns are poorly understood. The purpose of this study was to describe our department's experience at the epicenter of the e-scooter phenomenon that is sweeping the globe and to characterize operative orthopaedic injuries that are related to e-scooter accidents.

Methods

We performed a retrospective chart review of all of the operative orthopaedic cases and trauma consults at 2 trauma centers (a level-I center and a level-II center) between September 2017 and August 2019. We identified all operative injuries in which the cause of injury was an e-scooter accident. Data that included demographics, mechanism of injury, diagnosis, and treatment were collected.

Results

Seventy-five operative injuries were identified in 73 patients during the study period. The mean patient age was 35.4 years (range, 14 to 74 years), and the median age was 32 years. There were 4 pediatric patients (14, 15, 15, and 17 years old). Thirty-two patients (43.8%) sustained upper-extremity injuries, and 42 patients (57.5%) sustained lower-extremity injuries; 1 of these patients had both upper and lower-extremity injuries. Nine patients (12.3%) had open fractures. There were 7 hip fractures in patients with an average age of 42.4 years (range, 28 to 68 years). Seventy-one (97.3%) of 73 patients were e-scooter riders, and 2 (2.7%) were pedestrians who were struck by e-scooter riders.

Conclusions

E-scooters can cause serious injury. Seventy-three patients required operative treatment in just the first 2 years of e-scooter use in our community. Operative injuries occurred throughout the skeletal system, and several were injuries that are typically associated with high-energy trauma. Although, as a rule, e-scooter use is limited to adults and banned in high pedestrian-traffic areas in our city, the inclusion of 4 underage riders and 2 pedestrians in our cohort suggests that these rules are not always followed. As e-scooters continue to increase in popularity, additional steps should be taken to regulate their use and protect riders and the public.

Background

Previous studies have demonstrated that solid organ transplant (SOT) patients undergoing primary total knee arthroplasty (TKA) are at an increased risk of postoperative complications. The purpose of this study is to utilize a large, national database to investigate revision TKA (rTKA) outcomes in SOT patients.

Methods

This was a retrospective review utilizing the Nationwide Readmissions Database (NRD) and ICD-9 codes to identify patients who underwent rTKA from 2010-2014 with a history of at least one SOT. Propensity-score-matching (PSM) was used to compare rTKA outcomes in SOT patients compared to matched patients without SOT.

Results

A total of 303,867 rTKAs, with 464 of those being performed in SOT patients, were included in the study. Of these, 71,903 and 182 were performed for PJI in non-SOT and SOT patients, respectively. rTKA was performed most frequently in kidney transplant patients (53.0%) followed by liver transplant patients (34.3%). For non-PJI patients, SOT patients had a higher 90-day readmission rate than matched non-SOT rTKA patients (23.2% vs 12.6%, p = 0.006). However, there were no differences in 90-day readmission rates for specific rTKA complications, subsequent revision rTKA, or mortality. Among patients undergoing rTKA for PJI, there was no difference in overall 90-day readmission rate, readmission for specific rTKA complications, subsequent revision rTKA, or mortality.

Conclusions

While the increased medical comorbidities associated with SOT place patients at increased risk for complications following rTKA, it appears that SOT alone does not do so when patients are matched based on overall medical comorbidity.