Conspiracy theory: Frost injured his ankle on this trip, requiring surgery. They show everyone going down, but there isn't really anything on them going back up.
My guess is he tweaked his ankle on the trek back up and that's why they don't show much of it.
He said the surgery was to fix something from his playing days, which is probably true. According to Marty Smith's Twitter account, it looks like the trek occurred on May 21 or 22. Frost tweaks his old injury, then has surgery shortly after. That's why he was on crutches on the state tour in western Nebraska.
What does all of this mean? Nothing really. Just something that popped into my head watching the segment.