Commenting on the 24-year-old lock's injury, Ospreys head physio Chris Towers said: "Conor has been troubled by persisting problems with the articular cartilage of his right knee and unfortunately, it has not proven possible to overcome the problem.
"Despite continued hard work on his part and continued efforts to look after and preserve the knee he has not been able to cope with a full training load.
"We have had to withdraw him from training and playing following his last appearance in November against Connacht.
"Since then, we have conducted repeated investigations and specialist tests as well as consulting with several specialists to discuss and exhaust all the possible management and treatment options available to Conor.
"Unfortunately, the consensus of opinion is that there are no options available that would allow Conor to continue with a career in professional rugby."
A former captain of his country at age grade level, McInerney was ever-present in the second row when the Ireland Under-20s won the Six Nations Grand Slam in 2007.
He was restricted to just one Ospreys appearance off the bench during the 2009/10 season, against Leeds at the Liberty Stadium.
This season he managed an additional four appearances, three of them starts, the first of which came against away to Newcastle.
Speaking about his decision to hang up his boots, McInerney said: "Unfortunately I have been advised that I can no longer pursue a career in professional rugby.
"Whilst this is extremely disappointing news for any player to hear, I feel very fortunate to have been given an opportunity to make a living in the sport that I love in the first place.
"The disappointment is lessened somewhat by the fact that it is the right decision for my body.
"I am very thankful for the support and belief the Ospreys have shown in me since I signed two years ago, I feel incredibly fortunate to have shared this brief spell with such a great bunch of guys.
"I need to say a special thank you to the medical department at the Ospreys who I ended up getting to know probably a lot better than I would have liked, in particular Towers and Brían, the physios, and Pembo (doctor).
"I would also like to take this opportunity to thank my parents, friends and girlfriend who have supported me all the way through my journey in professional rugby.
"I'm now looking forward to achieving new goals and meeting new challenges in a different arena in the years to come. I wish everyone in Ospreylia the very best of luck into the future."
The Welsh region's Elite Performance Director Andrew Hore said: "As was the case with Ben Lewis earlier this week, it is incredibly sad when a young player is forced to call time prematurely on his career.
"In Conor's case, we brought him to the region ahead of the 2009/10 season having identified him as an outstanding prospect with the desire and characteristics to be an Osprey.
"While his injury has prevented him from showing us fully what he was capable of, he has managed to make a big impact within the environment and will be sorely missed.
"The appearances he has made in an Ospreys shirt showed exactly why we signed him, it's just a real pity that we won't get to see him build on those performances.
"Conor is a particularly strong individual with excellent leadership skills, he is intelligent and is currently completing the final stages of a university course, all of which should help ensure that he has a bright future ahead of him off the field.
"He has a number of options available to him at the moment, and whatever he chooses, we wish him the very best of luck. He will leave the Ospreys knowing that he will always be welcome back here."