There is really no difference between wrist wrestling and arm wrestling and in Canada, the two associations were merged in 1995.
I was at the provincial championships of British Columbia in Kelowna many years ago. I was a member of the Cranbrook wrist wrestling club at the time. and the provincials were on Skaha beach in Penticton. The tournament was held on a flatbed trailer and was in an awesome location hosted by Brian Marsh.
I was doing well at the championships and while arm wrestling a fellow from Northern BC (I did not know his name), the most horrific thing happened. His arm broke half way down the humorous (a spiral fracture). This is what happens when things go wrong. There may or may not have been a break arm position, no one knows but two referees were watching for this to prevent it. Unfortunately accidents do happen.

The break sounded like a light bulb breaking and I felt the break. I let go of my opponent's hand and turned away in dismay. I could not continue competing and left the tournament in disbelief. This bothered me for several weeks but because I was very young and busy I forgot about the traumatic event and got over it.
One year later, I was competing at the BC provincial championships again and midway through the tournament they called me and an opponent to the table. When we approached the table, it was the same guy whose arm broke the year before.
In dismay, I said to him “didn’t your arm break last year?” He looked me in the eyes and replied “that was right, this is left”
I was dismayed by this, could not arm wrestle this guy or continue to compete in the provincials. I forfeited this and my remaining matches. I left the tournament feeling sick.