Does systemic lupus erythematosus impact the peri-operative complication rates following primary total knee arthroplasty? A national inpatient sample-based large-scale study

Introduction Consequent to improved life expectancies, there has been a substantial increase in the proportion of patients with systemic lupus erythematosus (SLE) undergoing total knee arthroplasty (TKA) over the past 2 decades. In comparison to the other inflammatory disorders, the complication rates and post-operative outcome in patients with SLE are less clearly understood, owing to the paucity of evidence in the literature. Methods Patients who underwent TKA between 2016 and 2019 were identified (ICD-10CMP code) using the National Inpatient Sample (NIS) database and then classified into one of the two groups, namely those with SLE (ICD-10-CM; code710.0) and those without SLE (NSLE). Demographic details, co-morbidities, details regarding hospital stay, costs incurred, and complications encountered of this patient cohort were analysed and compared between the two groups. Results Overall, among 5,58,361 patients undergoing TKA, 2,094 (0.38%) patients had SLE. The SLE group was significantly younger than NSLE population (62.2 +/- 9.9 vs 66.7 +/- 9.5 years; p < 0.001). The proportion of female and African-American patients was higher in the SLE group (p < 0.001). SLE patients had a significantly longer hospital stay (p < 0.001) and greater hospital-related expenditure (p < 0.001). Among the peri-operative complications, SLE patients had significantly greater risk of developing post-operative anemia (19.2% in SLE vs 15.3% in NSLE; p < 0.001), requiring blood transfusion (2.8% in SLE vs 1.5% in NSLE; p < 0.001), and acquiring peri-prosthetic joint infections (1.9% in SLE vs 1% in NSLE; p < 0.001). Conclusion The presence of SLE significantly lengthens hospital stay, and augments the health-care-related costs in patients undergoing TKA. The rates of peri-prosthetic infections, post-operative anemia, and need for blood transfusions are significantly greater in SLE patients.