St. Moritiz, Switzerland AP  —  When Lindsey Vonn last raced on the World Cup circuit nearly six years ago, the constant pain in her knee left her in tears and led to retirement. Flash forward to Vonn’s comeback race on a titanium knee at age 40 last weekend, and the American skiing standout couldn’t have felt more different. No more pain. No more swelling. No more tears. “The last few years of my career were so much different than they are right now. I’m skiing without thinking about my knee,