You Can Do Arthroplasty in a Young Patient, But...: Commentary on articles by John P. Meehan, MD, et al.: "Younger Age Is Associated with a Higher Risk of Early Periprosthetic Joint Infection and Aseptic Mechanical Failure After Total Knee Arthroplasty," and Vinay K. Aggarwal, et al.: "Revision Total Knee Arthroplasty in the Young Patient: Is There Trouble on the Horizon?"