In the past, doctors reserved hip replacement surgery primarily for people over 60 years of age. The thinking was that older people typically are less active and put less stress on the artificial hip than do younger people. In more recent years, however, doctors have found that hip replacement surgery can be very successful in younger people as well. New technology has improved the artificial parts, allowing them to withstand more stress and strain and last longer.

via Questions and Answers about Hip Replacement.