Knee pain may be caused by factors such as bone trauma, degenerative joint changes and soft tissue injuries around the knee joint. 1. Bone trauma: the kneecap includes the femur, tibia and patella, etc. Damage can lead to localized swelling, pain, and limitation of limb movement. Especially after trauma, it may be accompanied by damage to the surrounding ligaments and joint capsule, which can cause obvious knee swelling, pain and limitation of movement. 2. Joint degeneration: As we age, joint degeneration and wear and tear can lead to many joint diseases, such as osteoarthritis, which can cause knee pain. 3. Soft tissue injuries around the knee: When performing strenuous exercise or experiencing a traumatic blow, the muscles, ligaments and meniscus around the knee are easily damaged, resulting in localized pain and limited movement. If knee pain persists without relief, you should go to the hospital in time for targeted examination to clarify the cause.