Many times in the books Watson would mention another case by title (The Adventure of the Grice Pattersons on the Island of Uffa) or a passing reference (Isadore somebody who was found stark raving mad staring at a box which contained a worm completely unknown to science), for example and they were never brought up again. This fight is likely a nod to those noodle incidents; the fight had nothing to do with the case.