What could cause sharp knee pain when descending stairs?

When you step down, extra pressure goes on the front part of your knee. This can cause pain if the area between the kneecap and the thigh bone is irritated. One common cause is patellofemoral syndrome. This condition happens when the kneecap does not move smoothly over the thigh bone. Sometimes, the cartilage under the kneecap gets softened or damaged—a condition known as chondromalacia patella—which often leads to sharp pain during activities like descending stairs. Other reasons that can cause pain include muscle imbalances around the knee or an injury that leads to swelling inside the joint. The extra pressure from stepping down stairs makes these conditions more noticeable because more force is applied to the kneecap and its cartilage. Taking time to rest, icing the knee, and doing exercises to strengthen the leg muscles may help. However, if you're experiencing persistent knee pain, you can check your symptoms to better understand what might be causing your discomfort, or see a doctor if the problem continues or gets worse.