Have a specialist (ortho surgeon or rehab doctor) check out your knee as not all doctors can perform a proper diagnosis. If said specialist thinks that there may be something there that merits a closer look, then an MRI will pretty much tell the whole story.
I tore my ACL and the ortho diagnosed this pretty quickly just by manipulating my knee but an MRI further revealed a small meniscus tear. I decided to have a reconstruction and did my rehab religiously. 6 months post-op, the ortho cleared me to kite again.
You can have your knees checked out all you want.
Both my father and brother are spinal and ortho doctors, world class with international soccer players and heads of state among their patients.
I showed them both my twin tips and what the stance is like in them, as well as two strap surfboards.
Both told me that they are a time bomb for your knees, even if your knees have no previous problems.
The rotational stress combined with the knee movement to absorb chop and landings is just WRONG. It's the dirty little secret of the industry.
One really needs to add strapless skills to ones kiting.
I know that there are certain kinds of fun that require straps. What I am getting to is DON'T use a board with straps all the time. You will pay for it in the long run.
One of the "gifts" the twin tip will give you is premature arthritis..... pain even when you sleep.
If you look at the development of boards you can see that something is wrong. They have added flex, added flex tips, added super plush foot pads... developed straps with laces..... all in an attempt to reduce the torture.
Doing sports your muscles are supposed to be tiered, not your joints.
Now apart from the constraints and bad ergonomics of twin tips and the twin tip stance (as well as to a lesser extent two strap directionals) the industry is going in the wrong direction with boards in my opinion.
Boards should be expendable and way less expensive. They should be weak enough to give before your knees do in a crash or bad landing. They should also be expendable from a safety point of view so you can let your board go if it's heading to the rocks or you are simply trying to rescue yourself.
The industry on the other hand is getting more and more expensive with claims of bomber build of there boards. Better, stronger ... bla bla bla... in the mean time they are just killing the knees of their customers.
I remember having these discussions with other kiters a few years ago and many literally telling me I'm full of s@#t. Those same people have problems today. Some have had very nasty damage and have to resort to riding with knee braces and or keep sessions short, no 2 days in a row kiting etc.
Now I don't want to be a Nanny, but someone has to point this out.
Just look at how often ACL surgery comes up. You can rest assured that if ACL surgery is so common other long term irreversible damage is being done daily.
Some people say that shit happens. That you are going to crash bad sooner or later and that getting hurt is just part of the sport. While there is some truth to that there is another thing that is very important to understand. Due to the very bad ergonomics of the twintip stance and straps in general you stress your knees to the point of rendering them vulnerable. Then what happens is that a crash that should not be a problem explodes your knee because you knee is "pre stressed"
This sport is really addictive, once you are in it you just have to ride, ride and ride. That's the good part, just take the right steps so that you can do it for 30 years
And come out dancing