HALIFAX - The NDP campaign has been hip-checked.

Jack Layton says his sister Nancy was mistaken when she told a St. John's shopkeeper the NDP leader had his hip replaced.

Nancy Layton was heard telling Canary Cycles owner Joe Planchat that her brother "had a hip replacement."

Planchat later confirmed those were the words she used.

But Sunday at a campaign stop in Halifax, Layton told reporters his sister was mistaken.

"It's not a hip replacement. There's definitely some metal in there to re-enforce the bone," he said.

"Some confusion. Inter-family confusion. I'll have to send her the X-ray."

Then, he mused: "Maybe we'll offer it to the media. Boy, I told you'd I'd strip, but nobody asked me for the X-ray. And nobody wanted me to strip, I might add."

Layton went under the knife last month to repair a hairline fracture that turned into a full-blown broken bone. He says he's not sure what caused the fracture in the first place.

Questions abounded about the NDP chief's health before the campaign. Could his bad hip endure five weeks on the campaign trail? Would he tone down his breakneck pace? Had he recovered from his battle with prostate cancer?

Layton has put those doubts to rest with spirited performances at stops across the country. He bounds up steps at rallies and hands his cane to an aide to hold while he's on stage.

That Layton's ailing hip still comes up at all is evidence of the struggle the New Democrats face as the campaign enters its fourth week.

The general consensus was that Layton came off well in last week's English and French debates. The NDP leader has tried to parlay that bounce into momentum as the campaign enters its last stretch.

He has made regional announcements at farmer's markets and shops in Atlantic Canada, but Layton's challenge now is elbowing his way back onto the national stage.