In recent years, there have been an increasing number of patients with knee pain, and many people have experienced knee pain, but the causes of knee pain are not well understood. The knee joint is the larger and more complex flexor joint in the body, which is subject to high stress and has a stable yet flexible structure. There are many causes of knee pain. Knee pain may be caused by a lesion in the knee joint, or it may be due to radiating knee pain triggered by lesions in the lower back and hip. Therefore, it is important to have a differential diagnosis by a physician specializing in joint surgery.
The causes of knee pain can be grouped into two main categories.
A. Knee pain caused by knee injury
1. Osteoarthritis of the knee joint
This condition is mostly seen in middle-aged and elderly people, mostly women. Overload is the main cause of the disease. The knee joint will be swollen and painful, and sometimes there will be friction sounds when moving the joint. The knee may have an inversion deformity with medial pain. Treatment is based on the metaplasia of the joint, and joint replacement therapy for osteoarthritis of the knee is now a more mature treatment internationally.
2. Meniscus injury
Meniscus injury is a common injury in athletes. When the lower limb is weighted, the foot is fixed, and the knee is slightly flexed, a sudden excessive internal rotation and extension of the knee or external rotation and extension of the knee (for example, in volleyball, the player suddenly turns and fishes to save the ball while defending) may cause a meniscus tear. A meniscal injury can be characterized by a distinct tearing sensation in the knee, followed by joint pain, limited motion, and a walking limp. The joint exhibits swelling and slippage and pops when the joint is moved. Minimally invasive arthroscopic surgery is usually required for treatment.
3. Knee ligament injury
The stability of the knee joint is relatively poor when it is slightly flexed, and if sudden external force causes valgus or valgus at this time, it may cause medial or lateral collateral ligament injury. Medial collateral ligament injuries account for the majority of clinical cases. In this injury, for example, the patient will have a clear history of trauma, pain and pressure on the medial side of the knee, increased pain when the calf is passively abducted, swelling on the medial side of the knee, petechiae will appear after a few days, and knee movement will be limited.
4. Improper exercise
Many people like to hike, but if they do not prepare for the activity or exercise too much, it can also cause joint pain. Especially people suffering from synovitis or osteoarthritis, more likely to cause joint disease attacks or aggravation. In mountain climbing, when descending a mountain, the weight of the whole body is put on one knee joint and the pressure on the knee joint is several times higher than when standing normally. The same situation occurs when people go up and down stairs.
5. Fat pad strain
The fat pad fills the gap at the front of the knee joint and has the effect of strengthening the joint stability and reducing friction. The cause of fat pad strain may be due to trauma or long-term friction that causes fat pad congestion, hypertrophy and inflammation, and adhesions with the patellar ligament, thus limiting knee joint movement. This injury occurs in people over the age of thirty who walk, hike or squat frequently. Patients may feel pain in the knee joint, which is worse when fully extended, but there is no restriction of joint movement. The symptoms are obvious after exertion.
6. Traumatic synovitis of the knee joint
The synovial membrane of the knee is one of the main structures that make up the knee joint. Synovial cells secrete synovial fluid, which can keep the cartilage surface of the joint slippery and increase the range of motion of the joint. Injury to the synovial membrane due to trauma or overexertion can produce a large amount of fluid, which increases the pressure in the joint and, if not eliminated in time, can easily cause joint adhesions and affect normal activities. Patients will feel pain, swelling and pressure in the knee joint, and the synovial membrane has a frictional and astringent sound. The most obvious feature of the pain is that when the knee joint is actively and extremely straight, especially when there is a certain resistance to do knee extension movement, the pain in the lower part of the patella will increase, and the pain is also significantly increased when it is passively and extremely flexed.
7. Bad walking habits
For example, often wearing shoes that do not fit the foot or walking long distances in slippers or high heels can put the knee joint in an abnormal state of stress for a long time, causing chronic damage to the knee joint and knee pain.
Second, the lumbar spine, lumbar spine or hip disease caused by knee pain
There are three nerves that dominate the lower extremities, they are the femoral nerve, the sciatic nerve and the closed foraminal nerve. People are familiar with sciatica, which to many is synonymous with lumbar disc herniation. The femoral and foraminal nerves are unfamiliar. In fact, lumbar spine pathology that affects the femoral and sciatic nerves can cause symptoms in the lower extremities. These symptoms include pain, muscle atrophy, soreness and swelling, coldness, numbness, coldness, heaviness and fatigue. The femoral nerve comes from the upper lumbar spine and innervates to the medial aspect of the knee and the front of the lower extremity. Any lesion in the tissues through which the femoral nerve passes can cause knee pain. From clinical experience, knee pain caused by lesions of the upper lumbar spine involving the femoral nerve is common, and most patients with knee pain can find obvious pressure points in the lumbosacral region, lateral hip (vastus fasciae, gluteus maximus, gluteus minimus), hip and groin (internal retractor muscle group). The effect can be immediate. Some patients with lumbar disc herniation also have symptoms such as knee pain and soreness, and when the lumbar disc herniation is cured, the knee pain symptoms will also be cured.
In daily life, most knee pain is not caused by trauma. Prolonged exposure to cold and large temperature differences are the main causes of knee pain. Especially in the fall, when cold and warm temperatures alternate, low temperatures or large temperature differences can cause muscles and blood vessels to contract, causing knee pain. If you encounter this situation, the first thing you should do is to keep warm as much as possible, you can use hot compresses; the second thing is to reduce the amount of exercise and let the joint rest. If the above methods do not make the knee pain better, then it is necessary to go to the hospital to clarify the cause of the knee pain so that it can be properly handled and treated.