Soft Tissue Reconstruction Does Not Compromise Infection Control in Chronic Knee Periprosthetic Joint Infection Treated with Two-Stage Exchange Arthroplasty Despite Increasing Complexity

The role of soft tissue reconstruction in infection control of knee periprosthetic joint infection (PJI) treated with a two-stage exchange strategy remains controversial. This retrospective observational study analysed consecutive patients with chronic knee PJI managed with a two-stage protocol between 2010 and 2023, comparing outcomes between cases requiring flap-based soft tissue reconstruction and those achieving primary closure. A total of 118 patients with a minimum follow-up of 24 months were included. Forty patients (33.9%) required formal coverage, including 25 pedicled medial gastrocnemius flaps and 15 anterolateral thigh (ALT) microsurgical free flaps. Reconstructed patients showed greater baseline complexity, with a higher number of previous surgical pro-cedures (3.03 vs 2.08; p = 0.0057) and a higher prevalence of diabetes mellitus and sinus tracts. Despite this, infection control was superior compared with non-reconstructed cases (100% vs 88.5%; p = 0.029). Within the reconstruction group, both pedicled and micro-surgical techniques achieved complete infection eradication; however, ALT flaps were associated with higher complication rates (53.3%), with partial flap necrosis being the most frequent event. The use of microsurgical reconstruction increased progressively over time, reflecting growing reconstructive complexity.