"It was starting to affect my batting and my ability to move freely in the field and run with no pain, so it was good to get sorted and hopefully that's the last of it.
"I could have kept battling through it, although I missed games because of it last season, but it got to the point where it was really frustrating me. The timing [of surgery] wasn't ideal - it would have been better in the winter - but it was decided with the medical staff at New Zealand Cricket that I'd be better off getting the operation done now, miss a third of the season and then be good to go."
Flynn is hopeful of a return to the crease for the Twenty20 competition early in the New Year, possibly even as early as the December 31 clash between the Knights and Canterbury Wizards at the Bay Oval if his rehab keeps tracking upwards.
Initially on crutches for a month, he has been limited to low impact cycling and swimming but has progressed to having a few throwdowns in the past week. He's hopeful of getting back in the nets in the next two weeks if he gets the all-clear from his surgeon on Friday.
"Indications are it's better than expected but I'm conscious I still need to get myself back on the pitch and play good cricket."
Flynn is unsure what the best form of the game would be to launch his comeback but admits anything would be better than sitting on the embankment watching.
"It's frustrating being a watcher and I want to be out there making a difference, although watching the boys win that last Plunket Shield game [against Canterbury] made watching pretty easy."
Flynn debuted for the Black Caps in 2008 and averaged 28.70 from 16 tests, with his last game for the Black Caps in 2009 against Pakistan. His form for the Knights in the past year, even with a dodgy hip, suggested he was on track for a recall.
"Long term I've got age on my side, and I wasn't going to get myself back in contention for the Black Caps if I wasn't 100 per cent fit.
"My goal is to get back in the Black Caps in all three forms of the game but getting back on the park and doing well for ND is the immediate plan."