You have gotten some very good advice from both sbyork and ladyjane -- it just depends on which way your daughter feels most comfortable. If it were me I would get a second opinion from a board certified orthopedic surgeon. I would be sure to take along a report of the problems that she had with the irregular heart rate so that the ortho could properly evaluate her as a surgery candidate.
If it were up to me, I would rather live with an adult with a limp than take a chance if her heart issue poses a significant risk. Either way she will probably have some pain and problems with arthritis as she ages. Been there, done that and I have pain 24/7
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Good luck and please keep us posted!