I'm wondering why are bacterial infections in the bone difficult to treat with antibiotics?

Osteomyelitis: Osteomyelitis is difficult to treat for several reasons. When antibiotics are used for bone infections, the patient is placed on the medications for 6 weeks through an iv. Even after the therapy, there's no guarantee that the bacteria was completely eradicated and won't cause problems in the future. Removing infected segments of bone, along with antibiotics, is much more effective.

See below: Bacterial osteomyelitis frequently involves areas of bone necrosis that require surgical debridement or amputation. Osteomyelitis frequently involves bacterial biofilms with inert non-replicating bacteria that are difficult to kill with antibiotics and which require prolonged treatment.