Excessive lateral pressure syndrome-MRI

32 year old male complaints of chronic pain following old injury. MRI shows femoropatellar incongruence with lateral positioning of the patella suggesting lateralization.This is refered to as excessive lateral pressure syndrome, better demonstrated in  various femoropatellar articulation X-rays.

Teaching points by Dr MGK Murthy :
Not an uncommon cause of chronic knee pain in young individuals. Could be detected incidentally or following trauma including post surgery for various bony injuries. Etiology could be tight lateral retinaculum / lax medial retinaculum.
The signal intensity could appear different on axial MR due to attenuation of the  medial retinaculum, their by making the lateral retinaculum look more black due  to compact type I collagen.Congenital cases could be represented by fascial bands.