No one can diagnose your particular problem over the internet, not even with the superb picture you've provided us with.
Health Stack Exchange is for educational purposes only and is not intended as a substitute for individualized diagnosis and treatment by a qualified healthcare provider.
However, discussing osteomylitis and impetigo might help you.
The garden-variety of impetigo is a superficial skin infection characterized by redness, broken skin, and serous fluid leakage which when allowed to dry form honey-colored crusts.
It is highly infectious, and untreated, it spreads to not only others, but to the surrounding skin, in that more lesions develop and cover a larger area of the body.
The most common offending organism is Staphylococcus aureus; Streptococcus is next. It is so superficial that it's one of the few infections that can be treated with a topical agent (Bactroban) unless there is too much skin to cover, making a topical treatment unwieldy.
Impetigo can sometimes infect deeper into the dermis resulting in deep dermal ulcer with a raised and indurated (hardened) surrounding margin. Then, it is called ecthyma. The infection may start in skin that has been injured due to a scratch or insect bite, and for this reason, the infection often develops on the legs. These infections need oral, and sometimes intravenous antibiotics.
Osteomyelitis is infection of the bone. It can be caused by a skin infection that reaches the bone, an open fracture (even long after the fracture and overlying skin has healed, or from spread of infection by blood into an area of bone. Posttraumatic osteomyelitis is more commonly seen in adults and typically occurs in the tibia (some part of the "shin" bone, which is where your skin lesion is.)
Osteomyelitis is a serious infection and more difficult to treat. S aureus is the most common pathogenic organism (Thus, if both doctors have S aureus from cultures, they can both take this as a "confirmation" of the diagnosis.)
Posttraumatic osteomyelitis requires a detailed history for diagnosis, including information regarding the initial injury and previous antibiotic and surgical treatment. Weight bearing and function of the involved extremity are typically painful.
The diagnosis of osteomyelitis should include imaging studies of some kind which confirm the diagnosis.
Although one can't tell which you have, the information provided here might help you to have a more informed dialogue with your doctor(s). At this stage, though, it's safe to say it's not the garden variety of impetigo.
Common Bacterial Skin Infections
Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America