Suggest Remedies For Stiffness And Crackling Noise In Knees

My daughter is 14 and she has problems with her knees...each time she bends up and down they make a crackling noise.....just recent it has begun to bother her more often and yesterday her the last two fingers on her right hand began to stiffen and she couldnt move them...the vein or bone in top of her hand raised .....it has been off and on paining and getting stuck all day....what should I do?