Having had a horse with locking stifles, I thought she could have that problem. But it's also one if the symptoms of EPSM/PSSM, and if I think about the "mechanics" if LS...the ligament is a tad lose, gets caught on the patella, and developing muscle to pull the ligament tighter helps for LS, it makes total sense that LS is one of the symptoms of EPSM. So in other words building up muscle(through work and appropriate diet), should " cure" the LS symptom.
My horse with LS never locked up while in race training. Never.