Postoperative Infection After Implant-Based Breast Reconstruction: Risk Factors and Clinical Burden in a Large Single-Center Cohort

Background: Implant-based breast reconstruction (IBBR) is the most widely used reconstructive strategy after mastectomy, but postoperative infection remains a major complication because it may require reoperation, implant explantation, and reconstructive failure. This study evaluated the incidence, determinants, and clinical burden of infection in a large single-center cohort. Materials and Methods: This retrospective observational study included 1537 reconstructed breasts undergoing post-mastectomy implant-based breast reconstruction. The unit of analysis was the reconstructed breast. Infection was defined clinically by erythema, pain, swelling, or secretion requiring antibiotic treatment, without requiring microbiological confirmation or formal surgical-site-infection criteria; this pragmatic definition reflects the retrospective nature of the study and should be considered when comparing results across studies. Univariate analyses were performed using chi-square, Fisher's exact, or Mann-Whitney U tests, as appropriate. Independent predictors were assessed by multivariate binomial logistic regression. Results: Postoperative infection occurred in 66 of 1525 reconstructed breasts (4.3%). Among infected breasts, 54 cases (81.8%) required surgery, whereas 12 (18.2%) were managed conservatively. Implant explantation was performed in 82 of 1525 reconstructions (5.4%), and infection accounted for 39 of 74 explantations with available indication data (52.7%). In multivariate analysis, longer operative time remained independently associated with infection (OR 1.005 per minute, 95% CI 1.001-1.010; p = 0.010; corresponding to OR 1.38, 95% CI 1.08-1.77, per 60 min increment). Prepectoral reconstruction was also associated with a higher risk of infection compared with retropectoral reconstruction (OR 2.31, 95% CI 1.03-5.16; p = 0.042). Additional analyses showed that prepectoral reconstruction was more frequently associated with bilateral procedures, nipple-sparing mastectomy, and longer operative time. In unilateral reconstructions, the association between prepectoral reconstruction and infection persisted. Conclusions: Infection after implant-based breast reconstruction remains a clinically relevant source of morbidity and frequently requires further surgery. Longer operative time emerged as the most consistent independent factor associated with infection in the overall cohort. Prepectoral reconstruction was also associated with infection, although this finding should be interpreted cautiously in light of reconstructive context and case selection.