What's the most effective way to treat bone infection?

And debridement. In certain instances, the help of either a vascular or orthopaedic surgeon is needed, to remove (debride) overwhelmingly infected bone, since no amount of antibiotic will achieve a high enough level to kill bacteria.
IV Antibiotics. It takes about six weeks for an infected bone to "turn itself over". During this time, it is important to have high concentrations of antibiotics overwhelming the bacteria hiding there. Giving antibiotics intravenously is the most reliable way to achieve this.