It is a different movement, so it is not a significant leap of logic. There are three (main) factors in determining whether you front squat, high bar or low bar back squat: 1) what are you training for? A specific sport that benefits from overall strength or particular expressions of power? If you want to be a weightlifter, there is no point in low bar squatting, but there might not be much in it for rudgy (as an example) 2) what is your anatomy like? Short legs? Do whatever. Long legs? Low bar might be "easier;" because less mobility is required, etc. 3) Do you want to look awesome, or like some guy doing ego half reps? If it's the former, do high bar... Having done all three types of squat at varying points, the one thing I have found to guarantee causing knee pain is rubbish (potentially dangerous) form, or poor movement that causes guarding patterns (avoiding primary pain)... But that's my personal experience.