The surgery was performed by Dr. Rick Wright, Dr. Matt Smith and Dr. Matt Matava at the Washington University and Barnes-Jewish Orthopedics Center in Chesterfield, Missouri.
Sanford is expected to be sidelined for five to six months.
Sanford, 22, joined the Blues via trade from Washington on Feb. 27 last season. The 6-foot-4, 203-pound forward went on to make 13 regular season appearances for the Blues, posting five points (two goals, three assists). The Salem, Massachusetts native also dressed in four 2017 postseason games.