Imaging of Foreign Body Reactions to Non-absorbable Sutures in Achilles Tendon Repair: Radiologic and Histopathologic Correlation in Two Cases.

Achilles tendon ruptures are commonly managed with surgical repair, often using non-absorbable sutures for their tensile strength. However, foreign body reactions have been increasingly reported, accounting for up to 2% of complications in some studies, compared to approximately 3% for wound dehiscence. We present two cases of biopsy-proven foreign body reactions following percutaneous Achilles tendon repair with FiberWire® (Arthrex, Naples, Florida) sutures. Both patients developed localized swelling and erythema months after surgery, without any systemic signs of infection. Ultrasound and MRI revealed cystic-like lesions along the suture path, accompanied by inflammatory changes. Surgical debridement and suture removal led to complete resolution of symptoms, with corresponding normalization on follow-up imaging. Histopathology confirmed a foreign body reaction with giant cells and reactive fibroblast deposition. These cases emphasize the importance of recognizing foreign body reactions as a potential mimic of infection or rerupture, guiding appropriate management.