What is the best martial arts for me?

I'd comment on Krav Maga, but I have not knowledge of it directly. Aikido I do have knowledge of so I hope my comments are helpful.

First off I'd say forgive me, but I question whether you never really understood front snap kicks. I spent about 6 years trying to hyper-extend my knees thinking that was the source of the power. I did that from age 8 to age 14. By 16, I had gotten a better idea but ever since I was 14, every time I bend my knees, I can hear them crack. I feel for you.

That issue, like it is for you, was one of the reasons that after I quit at 16 (long story) then came back to martial arts at 27, I didn't go back to Karate. I investigated all sorts of different schools in my area and was left with awe when I visited my current dojo.

In my case, its Aikido, but the style doesn't matter so much - its the school. Aikido for example has all sorts of opportunities for injury when training - its just less self imposed through repetition as Karate. In AIkido, the injuries are immediate, accidental and in some way related to your partner.

That said, I'll mention one example. We have a student in our dojo that used to be a western boxer. He had a hip replacement and will limp for the rest of his life. Does that stop him? Nope - he's on the mat like everyone else and yes, people do adjust in the sense that he takes ukemi a little different than everyone else but so what, he's doing what he needs to do to keep himself safe - his physical issues simply dictate a difference as to what he needs to do and that by nature changes how technique needs to be performed to be effective.

I consider it to be a great learning tool to be forced to adjust. I also appreciate him pointing out openings (with a light pop to the ribs or whatever) I didn't protect when he sees them.

I'd worry less about a specific style than I would about 'hard' vs. 'soft' and 'linear' vs. 'circular'. Rather, I'd visit as many dojos as I could and compare what your knees can handle vs. what the class is like... at that dojo.

Last comment... Aikido involves two types of situations that might not be acceptable for your knees. Suwari Waza - defense in Seiza from an attack from Seiza - and Hanmi Handachi - defense in Seiza from a standing attack. Seiza is all over the place in Aikido - if for no other reason that you will be sitting in it while Sensei is demonstrating, at the beginning and at the end of class.

On the other hand, I'm in the same boat as you and I've not had a problem with it.

There is no way around it really - to learn to protect and keep your body intact, you end up having to harm it. If you don't, you aren't learning as much as you can, it you do, you will pay the price over time. Ideally, it shouldn't be that way, be we are human and we aren't perfect.

Its not the styles we practice, its us that causes an injury we get - be it immediate or repetitive impact/stress related.

Edit - yupchagee - I'd say that in my experience, around half of the formal curiculum in my dojo at least are throws. Jiyu Waza could result in anything, but Randori definatelly has more throws than pins - when you are dealing with multiple attackers, to pin someone is to pin yourself and make defense against the other people trying to kick you in the head more difficult.

I also disagree with the idea that the throws are stressful on the knees. If anything, they are stressful on upper body joints when the throw is forced, but not on the knees.

The knees come into play when you are doing technique from a kneeling position. Then they get damaged due to repetition rather than stress in a given instance.

Not an absolute rule or course, but a decent generality in my experience.

I think both the styles you are considering will still be tough on your knees, Aikido is heavier use on the knees say than Aikijujitsu its for father or Ju Jitsu. Other styles you may consider are Judo where you are using your opponents body weight against them and less of your own. Maybe Tai Chi, now many will say Tai Chi is not for fighting, that is more or less correct, but it is GREAT for self defense once you have spent years studying it, you will move like the wind and never be touched. This will take a near life time to learn unfortunately but is great health for your body and knees mixed with Qui Qong or Reiki.

I would stay away from most the external arts for your knees and more of your body's sake. I was a full contact fighter for years and in the end have hurt my body badly from all the external Ki I have used and have not counter balanced with internal Ki. That is why I personaly wish to learn Tai Chi and qu Qong together to focus that internal Ki (Chi) to heal the damage I caused with external.

I hope this helps you decide on a direction, when it comes straight down to it the style will only matter if the teacher is able to teach it well so you can understand it. All styles are equal, practioners differentiate.

Krav Maga uses a lot of knee strikes. Probably not a good idea with bad knees. My guess is Aikido or Hapkido, which are grappling styles that mostly use joint manipulation rather than throws. Throws are likely to put more strain on your knees.

I'd do either muy thai or jujitsu. Muy Thai is a Big maybe if you think you can condition you shins and knee's to be used it doesnt have alot of kicking. Brazilian Jujitsu sounds more your style. It's heavily grappling oriented but it doesnt really used strikes only grapples. Also I'd stay away from Aikido although I havent done it myself I've fought practitioners and they arent really anything special

Check out Shim Gum Do

You will appreciate it alot.

jujitsu or pankration.