The 27-year-old former Scotland back ruptured his anterior cruciate ligament against Sale Sharks in the summer of 2011. The club's top try-scorer in the Heineken Cup made his return in December after a year and a half out of action, managing six games for the capital club, but there was another injury setback three months ago when more knee problems surfaced.
After undergoing his latest operation to improve the cushioning offered by his knee cartilage, Cairns will now work with the club's physios and strength and conditioning staff with the view to getting back to full fitness and making a case for a new contract.
Cairns has racked up more than 100 appearances for Edinburgh since his debut in 2006, as well as eight Scotland caps.
Edinburgh Rugby managing director David Davies said: "When fit, Ben is a quality player of international class and we'll do everything we can to help him back to full fitness.
"He's a local boy who has been a long-standing servant of Edinburgh Rugby, and I believe that commitment merits our efforts to give him the best possible chance of earning a new contract."
Cairns added: "It's been a frustrating couple of seasons for myself and Edinburgh Rugby, who have been fantastic throughout. I'm really grateful for the opportunity to stay part of the squad through this rehab period.
"It means a huge amount for me to represent my home club and I'm determined to repay the faith they have shown in me.
"With this being a completely new injury, I'm confident I can get back to full fitness and the form I know I'm capable of."
- Sports & Recreation
- Edinburgh Rugby
- Heineken Cup