It seems that you might be having osteo-artheritis of joint at this age.
Medicines you are given Calcium, vitamin A
,D and other supplements and some pain killer.
With this medicines you can not be cured but further damage in the joints can be prevented.
Go for physiotherapy
daily and regularly.
Go for Patellar exercise for 10 minutes for 2-3 times a day.
Avoid squatting or doing cross legs.
Ok and take care.