Sounds as though you need to rectify the problem of landing with your foot of a 45 degree angle when its hits the line if im understanding it correctly. Best technique is to have your landing foot pointing towards the stumps to avoid stress and strain upon the knees and ankles.
Maybe worth trying to place two sets of cones parallel to each other facing down the pitch on the ground so that you are forced to land with your toe pointing straight, by forming a repetition you will learn to correct the issue and by having a physical restrain from allowing you to land at 45 degress should help force it back on line.
Just my thoughts