Cambridge Dictionary reports that this is a newly recognized term. It’s a now and the definition is:
avocado hand noun [U] UK /ˌæv.əˈkɑː.dəʊ.hænd/ US /ˌæv.əˈkɑː.doʊ.hænd/
an injury that results when you use a knife to try to remove the stone from an avocado and cut your hand instead.
[Dr.] Simon Eccles, secretary of the British Association of Plastic, Reconstructive and Aesthetic Surgeons, explained how he now treats up to four people a week for avocado hand. When slippery fruit meets sharp knife and hard stone, intricate surgery is often required to mend the deep lacerations. [Excerpt from article in The Telegraph, 15 May 2017]
And a thank you to my lovely wife for pointing this out to me! (No, I haven’t done this yet.)