A large thigh abscess develops at the surgical site after a femoral artery embolectomy, is incision and drainage the only treatment required?

Possibly: If no graft or foreign body was included at operation, then adequate drainage may resolve the issue. I suspect most would use antibiotic as well, and culture the drainage to pick the best ones.

Yes: But most doctors will put you on antibiotics as well.

No: I and d, antibiotics and comprehensive wound care.

Yes: An abscess, or collection of infected fluid should absolutely be drained. If left undrained, it could compromise healing if the opening in the artery, and the suture line could blow out leading to a high risk of death. Call your surgeon immediately! an infection of the skin without and abscess is best treated with antibiotics.