Matthews was hoping to make a full recovery but suffered a setback in September and earlier this month the Ireland 'A' international was informed by a specialist in Belfast that his playing days were at an end.
He becomes the latest in a long line of Irish players to be forced to cut their careers short, following on from Connacht teammate Conor O'Loughlin, Leinster's Ian McKinley and Ulster's David Pollock.
"It was heartbreaking, I was gutted and it took a long time for it to sink in," said Matthews.
"There were a few tears as I realised this was it, there was no way back. That took time to sink in and I'm still coming to terms with it.
"It struck me in the stand against Toulouse and again last weekend against the Ospreys that I would never again experience the thrill of being out there, the buzz from the crowd when you make a break or get a tackle in.
"But that's what I need to adjust to. I'm not the first, nor will I be the last, to have his career cut short. I just thought I would get another two or three years out of playing."
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