The injury angle at Extreme Rules was done to explain why Kane did not do much in the ring during the Smackdown Tag Team Championship match.
For those of you that missed it, The Bludgeon Brothers attacked Kane backstage early in the show and that forced Daniel Bryan to wrestle most of the match on his own. Kane eventually walked down to the ring but he was wearing a protective medical boot and it was clear that he was very limited in the ring.
What actually happened was that he suffered an injury out of the ring but we don’t know when it happened or what caused it but it looks like it happened sometime during the last few days. During a campaign function earlier this week in Tennessee, he was seen wearing the medical boot (see the photo below) and he was wearing it backstage before the pay-per-view.
Following the show, WWE posted a storyline update to explain the injury. Their explanation was that his ankle was broken at the hands of The Bludgeon Brothers.
There is no word on his recovery time and when he is expected to return to action.