If you ever ride with significant pain that is unrelated to killing yourself on the bike, it can put a pretty significant damper on performance. Depends on pain type, intensity, and mental strength, but being anything less than 100% would be pretty tough on a stage like that.EDIT: So now there saying he was riding with a fractured left elbow. He's a seated climber. Tyler Hamilton hung with everyone and got on the podium that year he had a fractured clavicle, so I don't buy that the, "my elbow ruined his tour today" excuse.
Also, it seems that Tyler was pretty likely strongly doped up in more than one way at that point.