What causes pain in the knee joint when bending, and how should it be managed?

Knee refers to the knee joint. In general, knee pain during flexion may be caused by trauma, meniscus injury, knee synovitis, osteoarthritis, rheumatoid arthritis, and other reasons. It is recommended to seek medical attention promptly and receive symptomatic treatment under a doctor's guidance. Specific analyses are as follows:

1. Trauma

If trauma damages the knee joint or surrounding tissues, it may trigger local inflammatory responses and edema. When the knee bends, this inflammation and swelling may be stimulated, leading to pain and discomfort. Therefore, knee pain during flexion could result from trauma. Patients may follow medical advice to use medications such as Yunnan Baiyao Capsules, Sanqi Tablets, or Huoxue Zhitong Capsules for symptom relief.

2. Meniscus Injury

The meniscus consists of two crescent-shaped cartilage pieces located within the knee joint, primarily serving to cushion pressure, stabilize the joint, and reduce friction. When the meniscus is injured, the joint may experience additional pressure and friction during bending movements, causing pain. Under medical supervision, patients may use medications such as Indomethacin Tablets, Amoxicillin Capsules, or Diclofenac Sodium Sustained-Release Tablets to alleviate symptoms.

3. Knee Synovitis

Knee synovitis refers to inflammation of the synovial membrane in the joint. During flare-ups, the inflamed synovium may secrete excessive synovial fluid, resulting in joint effusion and increased joint load, thus causing pain during flexion. Patients may follow medical instructions to take medications such as Celecoxib Capsules, Ibuprofen Sustained-Release Capsules, or Methotrexate Tablets for treatment.

4. Osteoarthritis

Osteoarthritis is a chronic joint disease characterized by degeneration of articular cartilage, joint inflammation, and bone spur formation. In patients with osteoarthritis, the knee cartilage wears down, becoming thinner, losing elasticity, and potentially developing uneven joint surfaces. This increases friction between joint surfaces during knee flexion, leading to pain. Under a doctor’s guidance, patients may use medications such as Acetaminophen Tablets, Meloxicam Tablets, or Piroxicam Tablets for treatment.

5. Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune disease primarily manifesting as symmetrical, multi-joint inflammation and pain. If affected by rheumatoid arthritis, prolonged inflammation can lead to destruction of joint cartilage and erosion of bone tissue. During joint flexion, abnormal changes in cartilage and bone can cause pain. Thus, knee pain during flexion may be due to rheumatoid arthritis. Patients may follow medical advice to use medications such as Compound Cyclophosphamide Tablets, Etoricoxib Tablets, or Nabumetone Capsules for treatment.

In daily life, it is recommended to consume foods rich in protein, various vitamins, minerals, and other nutrients—such as eggs, lean meat, tomatoes, apples, etc.—to supply necessary energy and help maintain overall health.