I'm very, very curious why you say this is a myth? Keanes tackle ended Haalands active career. He never fully recovered.
Here: From a detailed writeup of the incident from ESPN:
"What happened next? Haaland was released by City in February of 2003 and retired soon after, unable to get his knees back to full working order thanks both to the challenge and a long-standing complaint. He considered legal action, but backed down and, in 2007, he was interviewed about the incident by the Daily Mail but could not bring himself to mention Keane by name. "It is still there, every day," the footballer-turned property developer said. "The knee still hurts, that isn't going to go away. I have to accept that. Did that tackle end my career? Well, I never played a full game again, did I? It seems like a great coincidence, don't you think?"
From the horses mouth. But I take it you are the stable master?