5 Answers

I couldn’t find an answer for you but I did find this information site for you:  

Where Can People Find More Information About Hip Replacement Surgery?

National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) 
Information Clearinghouse
National Institutes of Health

1 AMS Circle
Bethesda,  MD 20892-0001
Phone: 301-495-4484
Toll Free: 877-22-NIAMS (877-226-4267)
TTY: 301-565-2966
Fax: 301-718-6366
Email: NIAMSinfo@mail.nih.gov
Website: http://www.niams.nih.gov

I only know one person who had both done, and they waited along time to have the first one done, so the are convinced that it put extra pressure on the other one. 

Depends on the bone degeneration. My mother got one at 80. Better quality of life now.

Depends on the bone degeneration. My mother got one at 80. Better quality of life now.

Not that likely,and a hip joint called the Birimingham hip replacment,i beleve is quite long lasting,