The knee joint is the most prevalent joint in the body, and knee pain is perhaps one of the most difficult conditions to diagnose in all joints. It involves not only a variety of lesions within the joint, but is also often caused by a variety of extra-articular factors. The symptoms that arise in the knee are often non-specific. For example, symptoms such as pain, tender leg, and joint interlocking can be caused by either cruciate ligament or meniscal injuries, or by patellofemoral abnormalities, articular cartilage lesions, or may even be caused by mere ingrowth of an abnormal hyperplastic synovium. In addition, knee pain can also manifest because of extra-knee causes, such as low back disorders that may cause painful sensations behind the knee and hip disorders that may cause medial knee symptoms.
Causes of knee disorders can be divided into three categories: i. traumatic causes, which often imply damage to the internal and external stabilizing structures of the joint and other intra-articular structures; ii. strain causes, which often suggest muscle-tendon stop end disease, and iii. degenerative causes, which manifest as degeneration of articular cartilage, joint space narrowing and osteophytes.
I. Traumatic causes (sports injuries).
1. Acute knee ligament injury.
The ligaments are the stabilizing factors of the knee joint. There are anterior and posterior cruciate ligaments, medial and lateral collateral ligaments, etc. These ligaments, together with the joint capsule, maintain the stability of the knee joint. Lateral collateral ligament, capsular ligament and cruciate ligament injuries are quite common in trauma, especially in sports injuries. Ligament ruptures that are lost to early repair often leave behind varying degrees of knee instability. Unstable joints are prone to recurrent injury, leading to muscle atrophy or traumatic arthritis. There are many methods of late ligament reconstruction, but the long-term results are not satisfactory and the function of the original ligament cannot be fully restored.
After the anterior and posterior cruciate ligament injury, the main manifestation is the loose and unstable feeling of the joint, and the inability to complete the sharp turn and sharp stop and other actions, such as the sharp stop and jump shot when playing basketball, the sharp stop and sharp turn over or sharp stop and shoot when playing soccer. Can jog, but can not suddenly start accelerated running.
After the medial and lateral collateral ligament injury, the main manifestation is the inward and outward instability of the joint, and this instability can be felt when standing. Injuries to the lateral collateral ligaments are often combined with injuries to other structures of the joint, such as the joint capsule, meniscus, cruciate ligaments, and cartilage.
Injury to the ligament results in instability of the knee joint and abnormal movement between the femur and tibia, which can easily bruise the articular cartilage and meniscus and accelerate the degeneration of the joint. Early treatment is needed to repair and rebuild the knee joint to restore its stability.
2. Meniscal injury.
The meniscus is wedge-shaped and fills the gap at the edge of the joint, acting as a shock absorber and cushion to protect the articular cartilage. After the injury, pain in the joint can occur, mostly accompanied by joint effusion. When the knee is moved, a crisp sound can be heard on the injured side. When walking or doing a certain movement, the knee suddenly cannot be extended and flexed, often accompanied by soreness and pain, which is known as colic. The knee can “unlock” on its own after reextension and flexion or twisting, often accompanied by a sudden painful ringing.
The damaged meniscus not only fails to protect the cartilage, but can also aggravate the damage to the articular cartilage. It needs to be treated promptly by repairing and suturing or removing it.
3, patellar dislocation (acute or recurrent).
Patellar dislocation usually has a history of knee impingement or knee valgus sprain, and most people feel a popping sound of the patella moving wrongly to the side or wrongly below when injured. After the injury, blood accumulation in the joint, pain and swelling are more serious. On examination, the patella is looser when pushed to the side, and the fear test is positive. When the patella is dislocated, it is often combined with a tangential osteochondral fracture, and early surgery is necessary after diagnosis.
In recurrent patellar dislocation, if conservative treatment does not work, a different surgical procedure is required depending on whether it is combined with high patella and other abnormalities.
Second, strain causes.
1, quadriceps tendon stop end disease.
Long-term chronic strain can cause this disease, the lighter the pain only when jumping, the heavier the pain when going up and down stairs and walking. The upper edge of the patella is painful with pressure, slight local swelling and thickening, painful knee extension against resistance, but no patellar pressure pain, this point can be associated with chondromalacia patellae. Non-surgical treatment of this disease such as physiotherapy and functional exercise can achieve satisfactory results.
2, patellar tendon tenosynovitis and patellar tip end disease.
The two can be combined, mostly seen in people engaged in jumping, basketball, volleyball, also known as “jumping knee”. The main manifestations are jumping pain, up and down stairs pain, half squatting pain, playing soft leg, heavy running pain, and even walking pain. There may be atrophy of the quadriceps muscle, pressure pain at the patellar tip or patellar tendon, and thickening of the patellar tendon. Resistant knee extension pain.
Most of the non-surgical treatment of this disease can obtain a better result, and a few need surgery for lesion cleaning.
Third, degenerative causes.
1, patellofemoral arthropathy.
The main pathological change is degenerative degeneration of the cartilage, secondary to osteophytes on the edge of the patella or femur. Its main symptom is knee pain or knee tenderness, which is obvious when going up and down the stairs and reduced after rest. Secondly, semi-squatting pain is also an important symptom of the disease, and pseudocranial locking may also occur.
2. Excessive extrusion syndrome of the lateral patellofemoral joint.
The symptoms of this disease and patellofemoral arthropathy are similar and easily misdiagnosed, but the treatment and prognosis of the two are very different. Although the same discomfort of knee tenderness and semi-squatting pain is present, physical examination reveals that the patella is less mobile medially, and the lateral patellofemoral joint grind test is positive, while the medial patellofemoral joint grind test is negative, which is different from the positive grind test of the entire joint in patellofemoral arthropathy. This disease requires surgical release of the lateral support band, otherwise the condition will rapidly worsen.
3. Osteoarthritis.
Osteoarthritis is the most common disease of the knee joint in the elderly, mainly manifested as knee pain, starting with pain that increases with activity and decreases after rest, and later may become persistent pain. The joint accumulates fluid and swells repeatedly, sometimes in relation to weather changes. The knee joint may become inversion or valgus as the disease progresses, the bone margin of the joint increases, the mobility decreases, and in severe cases, the knee joint becomes flexion contracture deformity. x-ray shows joint space narrowing, osteophytes, and joint valgus deformity.
The treatment of this disease can be divided into conservative treatment and surgical treatment. Chinese medicine therapy combined with physical therapy can relieve joint symptoms and delay or even avoid surgery. However, for types of osteoarthritis such as meniscal injury, the effect of surgical treatment is more certain.