Modifying 30DS for bad knee

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I want an exercise DVD I can do at home, and really like the structured approach of the 30DS. However, I have a bad knee (ruptured 3 of the ligaments, including both cruciates) and shouldn't do anything TOO high impact. I've looked briefly at some clips from the DVD on YouTube, and I think the main issue I would have would be things like star jumps or anything that requires me to kneel. Can I modify it? If so, what can I do instead of those knee-hurty exercises? Or is there a better DVD out there?

(I will of course be discussing this with my consultant too, when I see him)