My moms knee suddenly started paining .she said hips and thigh get a bit numb feels like ants on them then it pains. please help?

Nerve issue: It sounds like she is having a problem with the nerves that come out of the low back and innervate the hips and lower extremities. She may have a problem like severe arthritis or other degeneration in her lumbar spine, or possibly a problem with a disk bulging on the nerves. There are various medications as well as physical therapy that can help- talk to your/her doctor.