"The knee is a hinge joint, kind of like a pair of scissors. If you open and close them in one direction all is well. But if you twist the handles, you can hear the blades grind against each other.
Altering the natural hinging groove is a big reason why people have noisy, crackling, crepitus-filled knees. To prevent it, you have to minimize lateral movement of the knee under an external load.
Most people are aware of the dangers that are associated with the knees collapsing inward during a squat. But not many people seem to be concerned with the other extreme ? knees too far outward. The truth is that each position comes with unwanted baggage.
The foot has three bony protuberances that are the foundation for balance. Together, they form what's known as the tripod. When the weight is too far inside or outside of the tripod (as with knees too far in or too far out), it inhibits the ability of the hips to do their job. This is crucial for a healthy functioning lower body.
The ideal relationship during any standing exercise is that the knee tracks over the second/third toe. If it's there, your weight has to be centered over the tripod, which allows for maximum hip involvement. Shoving your knees to the outside is great if you're having trouble with them caving in. Otherwise, you're just creating more problems."
Found it for you