The 29-year-old announced his return to competitive action by coming off the bench to score twice in the Magpies' dramatic 2-2 draw with Hull City on Saturday.
It was Cisse's first appearance since April, and the Senegalese is relieved to be back in action after a "difficult" absence.
"It was difficult for me. The doctors have done a very good operation," he told The Chronicle. "After it I went to Clairefontaine and they have very good people there who looked after me.
"When I came back here the medical team did the last job. They worked me very hard.
"Sometimes I was angry but I came back, started to run and became happy. I worked hard and now feel OK."
Newcastle travel to the Britannia Stadium on Sunday to face Stoke City.