Final answer:
The nurse can best prevent osteomyelitis in a client with an open fracture by providing appropriate wound care to prevent infection.
Step-by-step explanation:
The best way for a nurse to prevent osteomyelitis in a client with an open fracture is by providing appropriate wound care to prevent infection. This includes cleaning the wound thoroughly, applying appropriate dressings, and administering antibiotics as prescribed. By preventing infection, the risk of developing osteomyelitis is reduced.