The presence of foreign bodies in a wound is a key contraindication to primary closure because it significantly increases the risk of infection and wound complications. Foreign material can serve as a nidus for bacterial growth, preventing proper healing and leading to abscess or wound breakdown. Wounds with clean edges, minimal bleeding, and short injury duration are generally suitable for primary closure since they are less contaminated and more likely to heal well. Therefore, before closing a wound primarily, thorough exploration and removal of any foreign bodies are essential to ensure optimal outcomes.
Reference: Sabiston Textbook of Surgery, 21st Edition.