Mayo - chairman is Dan Berry, also have Arlen Hanssen, Robert Trousdale, Pagnano, and many other leaders on the field of joint replacement.
Tufts - New England Baptist (Bierbaum, McCarthy, Mattingly, Scott)
Rush - Rosenberg, Berger (2-incision THA), Paprosky, Jacobs, Della Valle
Stanford - Goodman, Maloney, et al
Utah - Aaron Hofmann, Peters, Dunn
Wash U - Barrack, Clohisy, et al
Iowa - Callaghan
HSS, HJD, Wichita, UCLA, and Harvard are strong joint programs as well.
These are some of the guys that are consistently at the important joint meetings and are at the top of their field.
There are many programs with strong joint replacement experience - chances are that you will get to do joint replacement surgery at any of these. Those that are fellow-heavy will result in less operating, but better connections for fellowship - if that is your goal.