"I had surgery, and despite being close to returning I've broken down a couple of times.
"Having taken medical advice I've had to come to this difficult decision, but I'm 34 and have had a decent career."
Ross joined the Fifers early on in the season, having had his contract cancelled by Hamilton after only three games at New Douglas Park.
But the full-back never managed to make a first-team appearance for the First Division side after suffering the injury in training.
"You have to be sensible about it and I've been fortunate," said Ross.
"There are a heck of a lot of players who aren't fortunate enough to reach the level I have, and others who have to curtail their careers a lot earlier.
"In a general fitness sense I feel good, but the demands of training and playing on a full-time basis - I wouldn't be able to do that.
"And, of course, there's the threat of doing further damage to my knee, which already has reasonable damage to it already."
Ross began his career in 1999 at Clyde, from where he secured a move to Hartlepool United in 2004.
After a season in England he returned to Scotland with Falkirk, where he remained until he transferred to St Mirren on a two-year deal in 2008.
In 2009 he earned a Scotland B cap in a 3-0 friendly win over Northern Ireland B.
Ross is also the chairman of the PFA Scotland players' union, and he writes a weekly blog for the BBC Sport Scotland website.
Source: BBC Sport
Source: BBC Sport