What anatomy indicates proper degree of rotation for the AP oblique knee with 45 degree medial rotation?

patella superimposed on the distal femur
1/2 the patella is free of superimposition from the lateral femoral condyle
open femorotibial joint
1/2 the patella is free of superimposition from the medial femoral condyle

1/2 the patella is free of superimposition from the medial femoral condyle

Rationale: AP oblique knee with 45 degree medial rotation indicates proper rotation when 1/2 the patella is free of superimposition from the medial femoral condyle.