The DC-10's were never totally outright replaced.
The first of the DC-10-10's were retired starting in 1994. The DC-10-10's on domestics were replaced by the 767's and even 757's in some places. The Carribean saw the A300 take over DC-10 routes. In the last few years of DC-10 service they were mostly on Trans-Con's & Hawaii routes. The Hawaii routes were taken over by the 763. The last DC-10 was retired on HNL-DFW on 11/21/2000.
The first MD-11's came in 1990 and were partially meant to replace the DC-10 on some of the International routes and to expand Asia service. The last MD-11 flew SCL-DFW on 10/15/2001.
The 777 is more or less a replacement for the MD-11 and to pick up some of the DC-10 type capacity. The was sort of a cap in the DC-10 range for a few years before the 777 arrived, but the 777 is a more flexible aircraft in terms of routes and capacity than the DC-10.
You can say the DC-10 was replaced by aircraft that more or less suited the routes better. Some routes became 757, 767, A300, MD-11, or now 777.