LOWER LIMB CELLULITIS IN THE THREE MONTHS BEFORE TOTAL KNEE ARTHROPLASTY INCREASES RISK OF PERIPROSTHETIC JOINT INFECTION AND INFECTION-RELATED COMPLICATIONS

Introduction While surgeons typically defer total knee arthroplasty (TKA) during active lower limb infections such as cellulitis, evidence regarding infection risk in patients with recent cellulitis remains sparse. Therefore, this study evaluated the association between cellulitis within three months before TKA and the risk of periprosthetic joint infection (PJI) and postoperative complications. Methods Using an all-payer administrative database (PearlDiver), we identified all patients who underwent unilateral primary TKA between 2010 and 2022. Patients with less than 90 days of follow-up were excluded. Patients who experienced cellulitis within 3 months before TKA (n=1,657, 0.25%) were matched using 1:3 propensity score matching to those without cellulitis (n=4,971) for age, gender, obesity, Elixhauser Comorbidity Index (ECI), smoking, diabetes, hypertension, and heart failure. Outcomes analyzed included the incidence of PJI at 90 days, 1 year, and 2 years postoperatively, as well as the rate of surgical site infections (SSI), sepsis, reoperations, and readmissions within 90 days postoperatively. Multivariate analyses controlled for age, gender, and comorbidity index. Results Cellulitis within three months before primary TKA was significantly associated with increased odds of 90-day PJI (OR 1.83, 95% CI 1.25–2.67; p<0.01), 1-year PJI (OR 1.94, 95% CI 1.43–2.64; p<0.001), and 2-year PJI (OR 1.93, 95% CI 1.46–2.50; p<0.001). Additionally, recent cellulitis was linked to significantly higher odds of SSI (OR 2.10, 95% CI 1.44–3.06; p<0.001), reoperations (OR 1.51, 95% CI 1.17–1.94; p<0.01), and readmissions (OR 1.50, 95% CI 1.23–1.83; p<0.001). There was no statistically significant association found for 90-day sepsis (OR 1.55, 95% CI 0.82–2.80; p=0.15). Conclusion One in 400 patients undergoing primary TKA experienced cellulitis in the 3 months before surgery. Lower limb cellulitis in the 3 months before TKA substantially increases the risk of PJI, SSI, reoperations, and readmissions postoperatively. These findings highlight the importance of thorough patient evaluation and optimized multidisciplinary management strategies. Additional research exploring cellulitis resolution timing and its influence on postoperative outcomes is needed.