According to the team, Perkins officially underwent arthroscopic knee
ligament reconstruction with meniscal repair at the New England Baptist
Hospital in Boston.
…The Celtics did not disclose a timetable for his return, but Perkins
suggested he would be sidelined for five to six months after the
procedure, which would peg his return at sometime in January or February
So it seems like it's an ACL tear and a meniscus tear. Not pretty. We hope for a speedy recovery, Perk.