For Dr John Barker, who leads a 20-strong surgical and research team at the Jewish Hospital at the University of Louisville, Kentucky, the news that Mr Hallam had found other doctors prepared to do that surgery was a bitter blow.
Earlier this year, Dr Barker went public with his team's intention to carry out the world's first hand transplant. Now he cannot mask his frustration, and his suspicions.
Mr Hallam, who lives in Australia, got in touch about three months ago. "He has been very forceful, saying that he wanted [the operation] done," said Dr Barker. "We told him we were going through the process, and that he would be one of half a dozen candidates for a transplant.
"A couple of days ago we rang his wife in Australia to verify the New York appointment. She said, 'He isn't going to meet you - he's got a hand now'."
The Louisville team has spent three years and $750,000 (pounds 470,000) on research, including minor transplants on 40 pigs. Dr Barker said the team in France "could have heard about our research when we talked about it at a convention, and then just run home and done it, without the background research that went with it".
That did not mean that the French team did not know the correct mixture of drugs to minimise the immune reaction, he added.
If the drugs fail, Mr Hallam's hand will blacken and die within days. That happened in Ecuador after 14 days following a less sophisticated attempt at a hand transplant in 1964.
"Skin is the most antigenic of all tissues, it has the strongest immune reaction," said Dr Barker. "We'll do it with a combination of drugs at low doses. But they have been very secretive about what drugs they're using."
The eight French, Italian, Australian and British doctors involved in Mr Hallam's surgery and recuperation were not available for comment, but none has published research to alert Dr Barker to the existence of a rival group.
"I know of three, maybe four groups here in the US or Canada who have been preparing to do this, but not any in the rest of the world," he said.
He has spent the last few days trying "really hard" to get in touch with Mr Hallam's hospital in Lyons to confirm or put to rest his suspicions.
In medicine, being the first with breakthrough operations is an excellent way to attract research grants, as well as a place in history. Coming second tends to be a confirmation of someone else's work.
Dr Barker fears the transplant will not work, and the bad publicity will harm his plans. But his team still intends to carry out a similar transplant. They have 100 volunteers who will be whittled down to about six on the basis of their psychology and immune system.
Dr Barker already has an organ procurement company scouring the US, preparing to remove a hand from a cadaver - with a relative's consent.