The 30-year-old Wellington Hurricanes player tore the ligament at a pre-season training session on January 31 and is likely to miss most, if not all, of the season.
"Surgery next month after I strengthen my knee and fix my MCL tear so post ACL surgery hopefully my knee will be stronger and heal better," Jane wrote on his Twitter account.
Jane, a prolific user of the social media microblogging site, also posted a picture of himself icing the knee with a packet of frozen peas labelling it "old skool" treatment.
He told media in Wellington earlier this week that he held slim hopes of playing rugby again this year, but everything "had to go well" and he would not be back until he was feeling 100 per cent fit.
Players with similar injuries have needed at least six months recovery and rehabilitation from the injury and Jane has already ruled out playing this Super Rugby season.