One of the main symptoms of Alzheimer's is having a bad memory, and over time this problem becomes much worse. Because of this, if your parent used to complain of knee pain but they have not complained since being diagnosed with Alzheimer's, you need to watch for signs that they may still be having problems. To help you, below are two problems they may be having, along with the signs they will have:

Osteoarthritis

It is common for elderly people to have arthritis, including arthritis in the knee. This is because the cartilage that covers the knee deteriorates, and over time there is no cartilage left. Once this happens, the bones in your parent's knee will start to grind together; this causes pain, swelling around the knee, and decreased motion. You will notice your parent feeling pain as they walk, and they may even walk with a limp.

A doctor can perform an x-ray on your parent's knee to determine if they have this problem. If they do, they will prescribe pain medication. Make sure you tell the doctor if your parent is on any Alzheimer's medications, however, to ensure the pain medication will not cause any type of interaction.

If pain medications do not help, the doctor will suggest a knee replacement. This surgery replaces the bones, joints, and cartilage, so your parent's knee will feel back to normal once they heal.

Osteonecrosis

Another problem that can cause knee pain is osteonecrosis; this problem is also called bone death, because the bones in the knee lose blood, and once this happens the bones die. In most cases this problem starts with the bones on the side of the knee, but the pain may start in other areas, such as the outside of your parent's knee. This problem could be caused by having knee trauma when your parent was younger, but doctors are not sure.

If your parent has this problem, they will have sudden pain in their knee and will feel more pain at night. The front and in side of their knee will swell, and these areas will be tender when touched. You will also notice your parent limping while walking, or walking much slower than they normally do.

The doctor will prescribe pain medication and may suggest a physical therapist to strengthen the muscles in your parent's knee. Because your parent is older, however, the doctor may suggest they have knee replacement surgery.

Talk with your parent's doctor, and they can give you more information about knee surgery and other treatments.