What is the reason why my dad always get knee pain? he is 67 years old man.

Knee Arthritis: There can be many reasons for knee pain in older men and the cause is determined by knowing character of pain, severity and presence of other associated symptoms like swelling, redness, duration of pain. Most commonly this is due to 'wear and tear' arthritis or osteoarthritis which results from joint use. When pain persists or worsens, or there are more symptoms, patients should see their doctor.

Wear and tear: Osteoarthritis (oa) also known as degenerative arthritis , is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion.