The Problem of the Aging Surgeon (2009)

As an example of quantitative difference, orthopaedic surgeons entering postdoctorate specialty education before 1979 obtained an average of 4 years of residency education after medical school. So a typical orthopaedic surgeon who is today 56 years old or older could not have been taught the technique of locked intramedullary fixation of femoral fractures during his or her residency education. So a typical orthopaedic surgeon who is today 66 years old or older could not have been taught anything at all about joint replacement during his or her formal residency education, and a present surgeon older than approximately 40 years old could not have been taught modern joint replacement techniques during his or her formal residency education.

Source: www.ncbi.nlm.nih.gov