Then it is just a question as to whether that is or is not a major factor for you. My gelding has some arthritis in his spine (went over backwards in a starting gate as a child), but it doesn’t stop him from doing anything he chooses to do, and he is 24. This is a difficult decision for you if you really like him, but no one else can make it for you. Arthritis can be managed without too much of a problem most of the time. We all get it sooner or later.
It is never the horse's fault