Dear slithy: just as there are obsolete occupations, there are obsolete occupational injuries. There used to be a medical diagnosis "Weavers bottom" in which long hours of sitting on a hard bench caused pathologic changes in ligaments and tendons, scarring and calcification, ultmately iincapacitating.
There was an analooous "Coachman's knee" from many hours sitting on carriage seat bracing posterior of knee against the front part of the seat.