Suggest Treatment For Sore Knee And Joints Pain

hi

My mom is having pains in her joints from last month.she has sore knee too.she can't even walk properly.she is working woman(nurse in goverment hospital).and one more important thing is couple of months (8mon) back she had surgery.some kind of tumor was there in her liver(fortunattaly not cancer tumor) what kind of treatment is better for her?so that as early as at least she can go for work.thanx in advance.