He made 12 European appearances in three seasons for the Dragons but sustained the injury playing against Benetton Treviso in the PRO12 earlier this season and has been advised to call it a day.
"Regrettably I have been advised that a successful return to the pitch is unlikely and ultimately could lead to me having significant problems with my hand in the future," said Willis
"I have had a great time whilst with the Dragons and will always cherish memories of typical Newport Friday nights, fantastic Rodney Parade crowds and playing alongside a great bunch of guys.
"I'm very grateful and proud for the opportunity to be a Dragon and the support which everyone at the Dragons, and our regional fans have shown me over the past 4 years."
But Willis won't be a stranger at Rodney Parade as he plans to stay in Wales for the immediate future and continue his support of the region's developing hookers whilst of course continuing to support the team from the terraces.
"I firmly believe that the squad are heading in the right direction and that the future is bright for the Dragons. This is typified by the number of our boys presently in the Welsh setup.
"Darren and the team are doing a fantastic job leading this team and by retaining the nucleus of the squad we can build on the foundations we have laid and bring some awesome rugby to Rodney Parade"
"I'd like take the opportunity to wish the team well for the rest of this season and for the future. Wherever I may be in the world, I will always keep a close eye on the fortunes of the Men of Gwent."
The Dragons travel to Stade Aime Giral this weekend to face Perpignan in the Amlin Challenge Cup.