Are there any restrictions to bone grafts for a bat Cohen? Which is allowed? Synthetic doesn’t work as well. Bovine or cadaver? Unfortunately, coral is not used in the US at this time.

ב"ה Shalom For these type of questions I always recommend to speak to a Rabbi in person, therefore in theory, in the case of a male Cohen, using a bone from a dead body for an orthopedic operation in which there is no danger to life, is forbidden. (See Nishmat Avraham on Yoreh De'ah 369) However, a female cohenet, has no prohibition to become Tamei to a dead person, therefore a bone from a cadaver may be used. ( See shulcham Aruch Yoreh De'ah 373: 3) All the best and a Refu'ah Shleima.