There are all kinds of rocking chairs, but there is only one chair in which to rock.

After falling off the stage and breaking his leg June 12 in Sweden, Foo Fighters frontman Dave Grohl sketched a design (while in his hospital bed) of a special chair on which he could continue to rock. He wasn’t going to postpone the Foo Fighters 20th anniversary tour of North America.

He designed quite a chair. It was more of a throne on which he perched Saturday at sold-out Xcel Center. It was a padded black chair with an elevated extension for the injured leg (now in a walking boot) atop an equipment case, surrounded by necks of guitars on the side and a circle of lights outlining the back of the throne, emblazoned with the Foo Fighters logo. And, of course, the chair magically rolled on its own (OK, electronically) up and down a runway extending from the stage.

And, stationed in this chair, Grohl rocked. In fact, the 46-year-old may have overcompensated. “Are you ready?” he screamed in his best leather-throated AC/DC voice before the curtain opened. And he came out hair swinging, fist pumping and leg kicking (the good leg) on “Everlong,” the Foos’ signature and the tune the band played on the final moments of David Letterman’s final show.

“If everything could ever feel this real forever,” Grohl wailed, putting the manic in maniac. “If anything could ever be this good again.”

Rock on, Dave!

Then the Foos tore into the punkish “Monkey Wrench” and “Learn to Fly,” which was so overamped the pilot would have missed the runway by a mile.

More than ever, Grohl seemed eager to please. But the affable, overly chatty, Everyman rock star — forget that he was the drummer in the monumental, Hall of Fame band Nirvana — was just being his true believer self. He believes in the power of rock ’n’ roll, he believes the show must go, he believes in giving the people what they want.

So what if this was a top-heavy show with most of the big hits early in the concert. So what if the Foos’ “Big Me,” a big hit, was given a slow, pseudo-acoustic version in the darkness with fans holding their lit cellphones aloft.

So what if Grohl scraped his guitar against his walking boot for a gimmicky solo. So what if he gave a shout out to Cannon Falls, where Nirvana made its 1993 “In Utero” album. So what if the Foos did covers of Queen, the Stones and Van Halen.

So what if the throne made it seem more like the Dave Grohl Show and not a Foo Fighters concert even though the other five members rocked hard, with precision and force.

So what if the performance that began with “Everlong” seemed overlong at about two-dozen songs and 2¾ hours.

Because the 15,000 fans — and Grohl — seemed overjoyed by it all.