The symptom of knee pain when bending down stairs and walking on the level road is fine may be caused by knee osteomalacia, patellofemoral arthritis, meniscus injury and so on.
1. Osteomalacia of the knee joint: frequent mountain climbing, running and other sports will lead to increased wear and tear of the bones of the knee joint, which is easy to form osteophytes. When bending the knee down the stairs, it will increase the friction with the surrounding tissues and produce strong pain, but when walking on a flat road, the joints and the surrounding tissue structure have less friction and do not produce pain.
2. Patellofemoral arthritis: the patella is easily damaged under the impact of external force and long-term movement, and the inflammatory reaction such as edema occurs and causes pain. When the knee bends down the stairs, it will increase the inflammatory stimulation of the patellofemoral joint and cause pain, but it is not easy to cause pain when the stimulation is small when walking on the flat road.
3. Meniscus injury: Improper exertion or excessive fatigue exercise will lead to damage to the meniscus structure around the knee joint, thus affecting the stability of the knee joint and leading to activity pain. Going down the stairs will increase the meniscus damage and friction with the surrounding tissues and cause obvious pain, but the stimulation of the meniscus under the flat road is smaller and will not cause pain.
In order to clarify the cause of the pain when bending the knee down stairs and walking on a flat surface, it is recommended to go to the orthopedic department of the hospital for a consultation and comprehensive examination.