Arthritis. Where i can get her operated.

Most probable cause at this age is osteoarthritis... It's a degenerative bone disease...There’s no cure for osteoarthritis as yet, but there are a number of treatments that can help ease symptoms and reduce the chances arthritis becoming worse...options are analgesics, NSAIDs,intraosseous steroid injection and hyaluronic acid injections,Physiotherapy like strengthening exercises etc ... Treatment depends upon the stage...since your doctor had suggested replacement surgery it may be in advanced stage...please attach your x ray film and other reports here to get clear picture of your mother condition... Or consult another orthopedic surgeon with all the reports and your mother they will do the needful.