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.