The 30-year-old Johnson sat out Houston's first organized team practice, two weeks after the procedure.
"Right now, everything is just focusing on making sure everything is right before I get back out here," Johnson said. "Nothing to panic about."
The five-time Pro Bowl selection was inactive for nine regular-season games last year with injuries to both hamstrings. He says he hyperextended the knee against Jacksonville on Nov. 27, his first game back after he missed the previous six. He finished that game and also played the following week against Atlanta before going out with a second hamstring injury.
Johnson returned for Houston's playoff opener against Cincinnati, catching five passes for 90 yards and a touchdown. The Texans were eliminated a week later by Baltimore, and Johnson returned home to Miami to resume rehabilitating his hamstring injuries.
During that process, Johnson said fluid continued to develop around the knee, and he and the team decided to treat it with surgery.
"We thought it had kind of calmed down," Johnson said. "I was back out doing offseason workouts, just running around and stuff, and it just kind of swelled back up. We felt like that was the best thing to do, get the knee scoped, get it fixed."
Johnson said the knee injury won't delay his preparations for training camp later this summer.
"Right now, I'm feeling fine, the swelling's gone down a whole lot," he said.
Johnson also hurt the same knee in 2007, underwent arthroscopic surgery and missed spring workouts. He returned in time for training camp, then had his most productive season in 2008, making 115 catches for 1,575 yards and eight touchdowns.
He played through a badly sprained right ankle for most of 2010, sat out the final two games and had surgery after the season. Johnson is now entering his 10th season, but says he's not worried about his durability.
"The past two seasons have been pretty rough for me," Johnson said. "I just don't want to be back in that situation again, where I have to miss seven, eight, nine games. I want to get back to that `1,500-yard Andre.' Hopefully, that can happen this year."
As the practice began, Johnson and quarterback Matt Schaub tossed short passes to one another on a separate field from the team. Schaub also sat out Monday's workout as he recovers from surgery on his right foot, but coach Gary Kubiak said he was just being overly cautious with him.