I could definitely be wrong here but wasn't he working on getting old people to walk again in the 1980s? Returning to intensive high impact sport came much later. One could make an argument that Merv has made a bigger difference to RL than any other former player.
I have no clue about his work with the elderly, but I do recall him being the surgeon that worked on Wayne Pearce's ACL in mid-1986 and Pearce very nearly made it back in time for the Kangaroo Tour. I think it was from around then that ACL's weren't the career ender they once were.