Ibaka started complaining of knee soreness at the end of February and, although an MRI scan showed no structural damage, the 25-year-old went under the knife since the pain persisted.
"Serge is a guy that always wants to be out on the floor, rarely misses time," Thunder general manager Sam Presti told ESPN. "But we felt like with where the symptoms were, we didn't think it was going to be improving, and because of that, this was the necessary step.
"These type of roughening episodes are not uncommon. They're really just the result of wear and tear, and it happens to athletes over time. Generally you like to deal with these in the offseason, but what separated Serge's a little bit, and kind of led us to where we ended up, is that he was having some swelling as a result of that."
Ibaka's injury is a huge blow for the Thunder, especially with the NBA Playoffs looming over the horizon.
"Obviously, a setback in terms of timing for us," Presti said. "It would've been ideal if this was something we could've attended to over the summer. But the long-term health of the player and the ability to play at a high level during the season is the most important thing."
Despite feeling sore and uncomfortable, Presti said Ibaka had been in excellent form as he had been averaging 14.9 points, 8.2 rebounds and 3.2 blocks since February 1.
"What he was experiencing over the last several weeks was not necessarily any significant pain, or really anything limiting," Presti said. "In fact, he was playing some of his best basketball, but as time went on and the swelling came back after the different steps were taken, he was experiencing some stiffness, and limited mobility and discomfort from that."