Injured 76ers center Andrew Bynum wasn’t at the Wells Fargo Center for Philadelphia’s game against the Boston Celtics on Tuesday night because he was visiting his longtime orthopedist, Dr. David Altchek of the Hospital for Special Surgery in New York, for an examination of his ailing knees.

The 7-foot, 300-pound Bynum, whose right knee continued to swell more than a week after taking part in his first practice of the season on Feb. 22, is considering arthroscopic surgery and is no longer confident he’ll play for the Sixers this season.

Bynum also visited with at least one doctor on Monday, Sixers CEO Adam Aron said in a pair of broadcast interviews.

“We’re all trying to gather information and see what the best course of action is,” Sixers general manager Tony DiLeo said. “I’m sure Altchek will have an opinion, our doctors will have an opinion, and Andrew, basically, will have an opinion. It’s just gathering information now. And like I said before, he’ll continue to rehab and see how that goes. The option of washing it out (with arthroscopic surgery), we’ll see what happens there.”

Bynum has been sidelined by bone bruises and damaged cartilage in his knees since September. The Sixers acquired him from the Los Angeles Lakers in a four-team trade in August.

He is making $16.9 million this season and will become an unrestricted free agent in July, when he’s hoping to land a long-term deal and a nine-figure pay day.

“He set it up. That’s his doctor,” DiLeo said. “I know it’s a late appointment, so I don’t know if we’ll hear (results) tonight or tomorrow. … (The swelling) has gone down. But the activity has gone down.”