MD-80's & 737's have some of the best safety records in the business. They are both running around a fatal accident every 3M flights. Note the Concorde had it's first fatal accident after about 60,000 flights.

If either had serious problems with it's rudder or jackscrew, they'd be falling out of the sky on a regular basis. Both are in excess of 30M flights, and fly millions of flights per year. For example, if they crashed every 60k flights, you'd probably see a crash a week. And remember, 60k flights is flying once a day for almost 200 years!