As I understand, your mother needs a total knee replacement.
You can visit an orthopaedic surgeon who has been fellowship trained in Joint Replacement to get optimal results.
Cost of surgery will depend on the extent of knee arthritis and type of knee implant/ prostheses best suited to her.
You can get further info at www.BoneJointSurgeon.com
Dr. Ravi Nayak
M.S. Ortho., AAOS Scholar (USA)
Visiting Surgeon, New York University Hospital for Joint Diseases
DePuy Fellow in Primary & Revision Joint Replacement