Hello,
Delayed wound healing can occur in vitamin C and vit K deficiency,diabetes,p-rotein deficiency,immunocompromised states and if the person is taking corticosteroids or immunosuppressants. So get your blood sugar levels estimated. For the wound, clean it with an antiseptic and apply topical antibiotics like Neosporin . Also you need to take some oral antibiotics for which I suggest you to consult a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
sorry, don't know where "broken tibia that won't heal" came from. Please ignore this tag. Thanks