An orthopedist is a doctor that is knowledgeable in taking care of the body's skeletal structure. To be correct is to be free from error. So, to "stand corrected" can be taken in the literal sense (a person's skeletal structure is now correct) or the figurative sense (I admit that I was wrong and will stand here corrected). 
Admitting a mistake : ' ' Like the orthopedist ' s patient , I stand corrected . ' '