Multidisciplinary Approach to Complex Lower Extremity Limb Salvage in Pyogenic Arthritis, Pyoderma Gangrenosum, and Acne ( <scp>PAPA</scp> ) Syndrome: A Case Report

Limb salvage using free tissue transfer in patients with rare autoinflammatory syndromes is poorly described, and the safety of microvascular reconstruction in this population remains uncertain. Hereditary pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome is characterized by dysregulated inflammation, pathergy, and impaired wound healing, raising concern for flap compromise and postoperative complications. We report a rare case of lower extremity free tissue transfer in a patient with PAPA syndrome. A 66-year-old woman with rheumatoid arthritis and PAPA syndrome presented with rapid wound breakdown, violaceous ulceration, exposed hardware, and periprosthetic joint infection following left total knee arthroplasty (TKA). Examination revealed an approximately 9 × 7 cm anterior knee defect with subtotal patellar tendon necrosis. After multidisciplinary optimization, she underwent single-stage irrigation and debridement, hardware removal, revision TKA with patellar tendon reconstruction using gracilis autograft, and immediate coverage with a 22 × 14 cm free latissimus dorsi (LD) muscle flap. The flap was anastomosed end-to-side to the anterior tibial artery with venous outflow via the venae comitantes and loosely inset to preserve future surgical access. The donor site was closed primarily. A 21 × 13 cm staged split-thickness skin graft was performed 1 week later, with adjunctive postoperative hyperbaric oxygen therapy (HBOT). Initial healing was uncomplicated, with complete graft take and donor-site healing. Four months postoperatively, the patient developed chronic sinus tracts and recurrent periprosthetic infection requiring flap re-elevation, debridement, and hardware exchange; the flap pedicle was preserved, and coverage maintained. At one-year follow-up, all wounds had healed; flap coverage was durable with acceptable cosmesis, and the patient was ambulatory for short distances without assistance. She was last seen infection-free and full-weightbearing 4 months later. This case demonstrates that microvascular limb salvage is feasible in PAPA syndrome when guided by multidisciplinary planning and strategic flap design.