Primary closure of a contaminated wound can trap bacteria and debris inside the wound, creating an ideal environment for bacterial growth. This increases the risk of wound infection, as the body's natural defense mechanisms are compromised by the closure. Proper wound management in contaminated wounds often involves delayed primary closure or healing by secondary intention to reduce infection risk. Therefore, the primary complication to anticipate after closing contaminated wounds primarily is wound infection.

Reference: Sabiston Textbook of Surgery, 21st Edition.