The knee joint is a large and complex flexion joint of the human body. It has a stable and flexible structure. However, it is more susceptible to injury due to the high stress it receives. The pain of the knee joint sometimes occurs. However, this kind of pain is often ignored or arbitrarily considered to be knee arthritis, especially in middle-aged and elderly people, who think it is pain due to joint degenerative disease. In fact, there are many factors that cause knee joint pain, and clinically there are strict diagnostic criteria for knee arthritis. It does not mean that knee joint pain is knee arthritis.
It is clinically believed that only the following 1+2, or 1+3+4+5, or 1+4+5 can be diagnosed as knee arthritis:
1. Repeated knee joint pain in the past month;
2. X-ray film (standing position or weight-bearing position) shows narrowing of the joint space, subchondral bone sclerosis and/or cystic degeneration, and osteophyte formation on the joint edges;
3. Age ≥50 years old;
4. Morning stiffness time ≤ 30 minutes;
5. There is bone friction sound (feel) during activity.
Article 1 must be met! If you have had pain once in the past month, then it cannot be diagnosed as arthritis.
Regarding Article 2: This is the manifestation of arthritis under X-ray. If knee joint pain occurs repeatedly in the past month and meets the X-ray manifestations of Article 2, then the diagnosis of knee arthritis can be definite. Careful readers have discovered that these two items do not require a doctor’s physical examination (Article 5), which means that the doctor only asks you to take a film, and then combined with the symptoms to tell you that you have arthritis, sometimes it is reliable !
Diagnosis of knee arthritis is the same as with or without Article 3, because as long as Article 1 plus Article 2, or Article 1 plus Article 4 and Article 5 can be diagnosed, why add this? Because it reminds us that young patients are often not arthritis.
As for Article 4, if the morning stiffness is ≥ 30 minutes, it is often not arthritis, and other diseases such as rheumatoid arthritis should be considered.
Regarding the bone friction sound (sensation) during the activities mentioned in Article 5, this is not the conclusion that the patient said that my joints rang and felt the joints grind, but the medical examination must be done by a doctor.
However, in the actual clinical process, regardless of the symptoms, signs and other laboratory test results, our doctors will advise patients to undergo X-ray examination, because X-ray examination is the “gold standard” for clinical diagnosis of knee arthritis!
In addition to knee arthritis, common causes of knee joint pain are:
1. Fat pad strain: The fat pad fills the gap in the front of the knee joint, which has the effect of strengthening joint stability and reducing friction. Fat pad strain may be caused by trauma or long-term friction that causes fat pad congestion, hypertrophy, and inflammation, and adhesion with the patellar ligament, which restricts the movement of the knee joint. The patient will feel pain in the knee joint, which is aggravated when it is fully straightened, but the joint movement is not restricted, and the symptoms are obvious after fatigue.
2. Meniscus injury: When the lower limbs are weight-bearing, the feet are fixed, and the knee is slightly flexed, if you suddenly extend the knee with excessive internal rotation or external rotation, it may cause the meniscus to tear. Meniscus injury will have obvious knee tears, and then joint pain, limited mobility, limp walking, and snapping when joints move.
3. Knee joint traumatic synovitis: The knee joint synovium is one of the main structures of the knee joint. Synovial cells secrete synovial fluid, which can keep the cartilage surface smooth and increase the range of joint motion. The synovial membrane is damaged by factors such as trauma or excessive strain, which will produce a large amount of fluid, which will increase the pressure in the joint. If it is not eliminated in time, it will easily cause joint adhesion and affect normal activities. The patient will feel pain, swelling, and tenderness in the knee joint, and the synovial membrane has a rubbing sound. The characteristic of pain is that when the knee joint is actively extended to the extreme, the pain in the lower part of the patella will increase.
4. Knee joint ligament injury: The knee joint has relatively poor stability during slight flexion. If it is suddenly subjected to external force to cause valgus or varus, it may cause medial or lateral collateral ligament damage. Most patients have a clear history of trauma, pain and tenderness on the inner side of the knee joint, increased pain during passive abduction of the calf, swelling on the inner side of the knee, and ecchymosis after a few days.
5. Others: immune diseases such as rheumatism, rheumatoid, ankylosing spondylitis, lupus erythematosus can cause knee joint disease; knee joint pain caused by metabolic diseases such as gout has a significant upward trend in recent years.
The above-mentioned injuries that cause knee joint pain cannot be healed by daily health care alone. Therefore, once knee joint pain occurs, seek medical attention as soon as possible to confirm the diagnosis, so as not to delay the best time for treatment.