Which of the following is NOT categorized as a biologic complication?

• A. Irritation/Infection
• B. Compartment Syndrome
• C. Hematoma Formation
• D. Pin-bone Interface Failure

Answer: (D)

Biologic complications are those tied to how the body's tissues respond to implanted hardware or injury—things like infection, local tissue irritation from contact with hardware, or bleeding into tissue that forms a hematoma. A compartment syndrome fits into tissue pathology as swelling increases pressure and tissue perfusion is compromised, which is still a tissue-level complication. The issue at the pin-bone interface, however, is primarily mechanical: the pin loosens, migrates, or fails at the bone interface due to how forces are applied, micromotion, or insufficient purchase—problems rooted in mechanics rather than the body's biological response. Because of that mechanical nature, pin-bone interface failure is not categorized as a biologic complication.