Higher Superficial Infection Rate with Total Ankle Arthroplasty as Compared to Total Hip and Total Knee Arthroplasty

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Background: Infection following total ankle replacement is a serious complication, often requiring further surgery, including revision ankle arthroplasty, conversion to ankle arthrodesis, or even amputation. Due to thinner soft tissue coverage, abundance of eccrine sweat glands in the foot, and use of closed footwear, etc. the reported infection rate for total ankle replacement (ranges between 1.2% and 8.6%,) has been higher than that in hip and knee replacement (around 1-2%). However, there is still no study to directly compare the infection rate among total ankle replacement, total knee replacement and total hip replacement. Purpose of study: using American College of Surgeons’ National Surgical Quality Improvement Program (ACS-NSQIP) database to compare the infection rate among total ankle replacement, total knee replacement and total hip replacement. Methods: American College of Surgeons’ National Surgical Quality Improvement Program (ACS-NSQIP) database was utilized to identify patients undergoing primary total ankle replacement (CPT 27702), total knee replacement (CPT 27447) and total hip replacement (CPT 27130). We excluded primary diagnosis of fracture or infection, and those undergoing revision surgery. Variables of interest included patient age, BMI, smoking, comorbidities, total operating time, superficial infection, deep surgical site infection, wound dehiscence, venous thromboembolism (DVT), unplanned return to operative room (OR), and unplanned reoperation, etc. Statistical analysis was performed using STATA. Comparison of continuous variables were performed using Student t test or Mann-Whitney U test and χ2 test of independence and Fisher exact test for categorical variables. P values < 0.05 was set as the threshold for statistical significance. Results: 1430 cases of total ankle replacement, 308168 cases of total knee replacement and 199967 cases of total hip replacement were identified in ACS-NSQIP from 2017 to 2021. The demographic information was summarized in table 1. Operating time for total ankle replacement is much longer than total knee and total hip replacement (152.4 min vs 90.5min and 91.4 min, P< 0.001). Superficial infection rate for total ankle replacement is significantly higher than total hip replacement (1.26% vs 0.77, P< 0.05), without significant difference as compared to total knee replacement (1.26% vs 0.94%, P>0.05). However, the rate of return to OR for total ankle replacement is significantly lower than total hip replacement (0.77% vs 1.76%, P< 0.01), without significant difference as compared to total knee replacement (1.26% vs 1.02%, P>0.05). Conclusion: This study directly compared the complications among total ankle replacement, total knee replacement and total hip replacement. Although the operating time is much longer for total ankle replacement, the superficial infection rate for total ankle replacement is only a little higher than total hip replacement, without obvious difference as compared with total knee replacement. Interestingly, the rate of return to OR for total ankle replacement is lower than total hip replacement. Overall, total ankle replacement surgery is a safe procedure in term of complications, in spite of more risk factors. Table 1, demographic information