1999 Mercury Sable Tie Rods and ball joints.

I had a mechanic fix my car and replaced the brake pads, rotors, inner and outer tie rods. Bought new tires two weeks later. Two months later had to replace the same tires I had just bought because there was not tread left and the belt was wearing through. When 2nd set of new tires was being put on they showed me that the jam nut for the passenger side inner tie rod was not secured. They also told me the ball joints were ruined. Could the mess up with the tie rods have contributed to the busted ball joints? They were fine when they told me all the work that needed done two months before and supposedly fixed the tie rods and brakes. What do I need to have checked to make sure the car is safe? In other words what problems could this have caused to the suspension?