As a former ramp rat/marshaller, I can verify that (at least as of about 5 years ago) UPS air hub in Louisville, which is of a pretty similar size to FedEx's Memphis operation from what I understand, was using pushbacks on only one of four ramps, mostly on 757s. Getting the aircraft out of spots was a little "tricky" if the inbound marshallers had messed up a bit. What effect this has on sideload fatigue on a DC-10, I obviously can't say, and I might point out that a lot of the aircraft we were nosing out of tight spots were very high time super 70 series DC-8s, and none of them had catastrophic landing accidents that I'm aware of. Nor am I making any claims expressed or implied w/r/t the cause of this particular accident.