Why does my knee crack when I straighten it?

anytime I bend my left knee, like for example when I sit cross legged on the floor and then I try to stand up or straighten my knee it makes this painful crack. It always hurts when it cracks but sometimes it hurts more than others. Do I have something I should be concerned about? I’ve had this problem for a quite a while and I’m only 17 I’m guessing it could be because I played basketball for a while and that was the leg I used to jump when driving in for a layup.

5 Answers

  • It sounds like you have a build up of calcium in your joint, but without a few tests I couldn’t say for certain. Here’s a link to check it out.


    Sounds like you need to see a doctor.

  • I’m 20 and this happens to both my knees quite frequently. I played basketball and ran track in high school so I attribute the cracking (popping) to playing sports. You’ll probably grow out of it since you are still young like I am.

    Don’t stop playing basketball. I did and that’s when my knees got bad. Trying to get back into it though

  • Its simply wherein your cartilage hasn’t thoroughly built. Im sixteen and my ankles click on so loud it appears like anyone clapping or shutting a door. People have even heard it crack over the sound of a bus engine earlier than. It must quit doing it over time as your cartilage develops however dont drive your knee to do it. If you believe the bone grinding after you are 18ish then perhaps you must see a health care professional to examine the development of your cartilage growth.

  • It is only natural that the joint is releasing the trapped air. This will happen in almost all joints, & only those of fingers- legs & hands- we can feel it . It would not hurt you or your joints in the long run !

  • Go to the doctors and he’ll look at it and you can get an appointment for an xray.

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