There was a frame in the Stephen Maguire v Mark Davis match in Bahrain today that finished 49-1 to Davis.
The 50 points scored thus equalled the lowest aggregate frame score in a ranking event match. Graham Horne and Barry Mapstone also aggregated 50 in a frame during a qualifying match for the 1996 British Open qualifiers. Horne won the frame 34-16.
This is slightly misleading, though, as it does not include frames where players have conceded at ridiculously early points, as several have over the years.
Therefore, the record only applies to 'proper' frames.
Regardless, it's not really the sort of record you'd want to hold.
EDIT: This may all be nonsense (see comment below)