Geez Louise. Who would think that so many things can happen to such a small but crucial joint. I mean we got a mess of stuff in there. Tendons, ligaments, cartilage, bone, and bursa glands all needing to work properly to be able to support your weight and bend when you want them to.
Besides the ankle the knee has to support all your weight. SO when there is pain down there it tends to slow you down and frustrate your plans considerably.
So you can get a feel for what part is injured by doing a few of these system checks.
Tendons – connect muscles to your bones so the muscle has something to pull against to make the bone move. Like a pulley system. Tendon pain is crampy with bending and re-straightening. Best when at slight bend.
Ligaments – connect bones to other bones so we don’t fall apart so easy. Ligament pain is sharp and lancing when leg is straight and you are trying to rock it side to side or forward and back.
Cartilage – is a spongy soft shock absorber between where all the bones come together. Cartilage pain is a dull ache with a grating sound when we bend and straighten. If it is the meniscus cartilage then the knee also likes to lock, buckle when walking and pain is worse when try to pivot side to side.
Bursa glands – are small glands that lubricate joints (like an oil can). Bursa pain is a deep dull ache just underneath knee cap. Worse with bending better with straightening knee.
Bones – Got femur, tibia, and fibula all meeting together at the knee. If bone bruise or fracture then can’t bear weight on it. Pain is sharp when you try, dull ache when at rest.
Muscle - hooked to knee by tendons. Muscles swell and pain is crampy. Worse with bending and re-straightening.
If you have knee pain the best thing to do is follow the acronym R.I.C.E. which stands for Rest, Ice, Compression, and Elevate. Rest in best position that gives least pain, Use crutches when have to walk. Ice for 20 minutes every hour for 1st 2 days of injury. Knee brace or ace wrap to give support and keep swelling down. Elevate 6″ above level level of heart to get blood to flow out of leg and not pool and swell in the knee. Good luck with that.