Knee pain, along with numbness in the feet for a long time (like one year), can have several possible causes, and it is important to look at both symptoms together. Knee pain is often due to joint problems such as wear and tear (arthritis), overuse, or injury. At the same time, numbness in the feet usually points more toward a nerve-related issue rather than a joint problem. This can happen due to conditions like nerve compression from the lower back (such as a slipped disc or sciatica), long-standing diabetes causing nerve damage, or poor blood flow to the legs. Sometimes, these two problems may be separate but happen together, or they may be linked through nerve involvement. Because the symptoms have been present for a year, it is important not to ignore them. Your father should see a doctor for a proper check-up, which may include blood tests (like sugar and vitamin levels), and possibly scans of the spine or knee to find the exact cause. Early diagnosis can help prevent worsening and improve comfort.