I don't think just because they do one little skip necessarily means anything.
Sometimes dogs just do this, either because of stepping on something, or just
for no reason. I think it's good of you to check it out, for sure, but no need to
panic!
I'm sure Apple will be fine.
I wouldn't go thinking the worst
right away and looking into surgeons. Most dogs diagnosed with LP can live
perfectly normal w/o any surgery, just some supplements to make their joints stronger.