Osteoarthritis is a common rheumatic disease in middle-aged and elderly people and had many names, such as degenerative arthritis, proliferative arthritis or osteophytes, deforming arthritis, osteoarthrosis, etc. All these names reflect one aspect of osteoarthritis from different degrees. In general, osteoarthritis refers to a synovial joint disease characterized by cartilage loss with reactive hyperplasia of the periarticular bone.
It can be divided into primary (idiopathic) and secondary according to the presence or absence of a clear cause; limited and generalized according to the distribution of affected joints; and symptomatic and asymptomatic (radiographic) osteoarthritis according to the presence or absence of symptoms. The incidence of osteoarthritis gradually increases with age. The prevalence varies among different regions, races and populations. Preliminary epidemiological surveys in China show that the prevalence of osteoarthritis of the knee is 9.56% and up to 49% in people over 60 years of age. It is more common in women than in men.
The etiology of osteoarthritis is not fully understood. Associated factors include genetics (family history), advanced age, obesity, sex hormones, low-calcium diet, excessive exercise, and local trauma. The most important of these factors are genetics, increased age and localized overexertion.
The basic pathological changes of osteoarthritis include at least two aspects.
1. degeneration of articular cartilage.
2. osteophytes at the joint edges. Normal articular cartilage has a high water content, about 75% or more, and the outermost layer is smooth and dense, with radially arranged colloid fibers, around which a large amount of water is fixed, like a water bag with many soft separations, so that when there is pressure at a certain point, the pressure can be evenly dispersed, and the bone surface under the cartilage is evenly stressed, so that microfractures do not occur in the bone trabeculae under the stress point. On the outermost surface there is also a layer of sticky and slippery synovial fluid, which is secreted by the synovial membrane around the joint and plays a role in lubricating the joint and nourishing the cartilage. When a joint is subjected to impact loading, the muscles and bones absorb most of the stress and energy, with only a small portion being absorbed by the articular cartilage, a process in which the neuromuscular feedback system plays an important role.
As age increases, the ability of muscles and bones to absorb stress and the speed of neural reflexes gradually decreases, and the impact load on articular cartilage gradually increases, increasing the chance of injury. At the same time, the repair ability of articular cartilage slowly decreases, and when cartilage damage occurs, incomplete repair begins to leave small traces, but as long as the subchondral bone plate remains intact, the damage will not develop quickly, but the subchondral bone can also degenerate with age, resulting in damage to the integrity of the subchondral bone plate. Cartilage damage accumulates with age, then there is focal softening, surface roughness, decreased elasticity, followed by small flake loss, tiny cracks, erosions, ulcers, and large pieces of cartilage loss can leave the subchondral bone plate exposed.
When the dense layer is damaged, the water-holding capacity of cartilage begins to decline, and when pressure is applied, the pressure cannot be effectively dispersed, and the direct impact on the subchondral bone can cause trabecular fracture of the subchondral bone, and the microfracture of the trabecular bone that occurs continuously makes the strength of the subchondral bone weaken, which in turn increases the chance of cartilage damage, forming a vicious circle, and in severe cases, the subchondral bone plate is cystic (i.e., a small cavity is formed ). The human body has a complex and sensitive regulatory mechanism, and when this damage is perceived in order to reduce the local pressure on the cartilage and increase joint stability, a protective compensatory change of DD osteophytes (i.e., osteophytes or bone spurs) is produced, which manifests as osteophytes within the subchondral bone marrow cavity and osteophytes at the joint edges.
In the early stage of this compensatory disease, patients have no clinical symptoms until the microstructure of the subchondral bone is significantly altered or the hyperplastic bone flab irritates and compresses the surrounding nerves, blood vessels or synovial membrane causing an inflammatory response, or even causing instability of the affected joint, joint deformation and misalignment in severe cases.
Osteoarthritis is a chronic, progressive joint lesion that mostly involves weight-bearing joints and small joints of the hands and is clinically characterized by pain, deformation or limited movement. Although the pathological basis for degenerative joint changes is found in the early 20s, primary osteoarthritis is rarely seen before the age of 40. Therefore, osteoarthritis is the leading cause of joint pain in middle-aged and older adults.
The most common sites of osteoarthritis are the small joints and weight-bearing joints of the hands, which can be painful, deformed, and limited in movement, but can also have only x-ray manifestations without conscious symptoms. The most common sites are the distal interphalangeal joint, proximal interphalangeal joint, first metacarpophalangeal joint, knee joint, hip joint, first metatarsophalangeal joint, and the cervical and lumbar spine in that order. Men are generally more likely to have lumbar spine osteophytes, while women are more likely to have osteophytes in both knee joints, with different manifestations depending on the joints involved. The small joints of the fingers are often bony and swollen, with distal interphalangeal joint enlargement called Heberden’s node and proximal interphalangeal joint enlargement called Bouchard’s node, and the first metacarpophalangeal joint involvement may have a square hand-like appearance.
Knee involvement may limit the extension and flexion of the lower leg, and early on it is characterized by pain when going up and down stairs, especially when descending stairs. In the cervical, lumbar and thoracic spine, in addition to limited anterior, posterior, left and right movements of the vertebral body, the involvement may also manifest as discal, medullary, vertebral body pain or nerve root compression symptoms. For example, osteoarthritis of the cervical spine causes neck and shoulder pain and numbness of the upper limbs, while osteoarthritis of the lumbar spine can cause radiating pain and numbness of the lower limbs in addition to low back pain. In addition, cervical spine osteoarthritis can cause dizziness and vertigo when the vertebral artery is compressed by bone spur growth. Often osteoarthritis is a chronic progressive clinical process, with occasional acute redness, swelling, and pain, often in a single joint, and is sometimes easily confused with infectious arthritis or gouty arthritis.
However, regardless of the variability of the clinical manifestations of osteoarthritis, there is a common x-ray characteristic change: marginal osteophytes, or bone growths, in the affected joints. In the finger joints, this may appear as Heberden’s or Bouchard’s nodes, while in other joints, the marginal osteophytes may protrude significantly above the bone margins, forming so-called “spurs. Because the essence of osteoarthritis is degenerative changes in articular cartilage and poor cartilage repair, there is often asymmetric narrowing of the joint space in the mobile joints, sclerosis and deformation of the joint surface, subsurface cystic changes, and even loss of cartilage fragments into the joint cavity to form “joint rats” on the x-ray in the middle and late stages.
In primary osteoarthritis, the disease progresses slowly and the prognosis is generally good. For example, osteoarthritis of the hand is usually only moderately painful and rarely affects function. However, weight-bearing joints such as the knee and hip are susceptible to limited motion and even disability. In the United States, the number of retirements due to osteoarthritis accounts for more than 5% of the total number of retirements each year, which is comparable to the number of retirements due to heart disease, and the cause of hip and knee replacements is mostly osteoarthritis.
Treatment of osteoarthritis should be done early, especially for weight-bearing joints, because the regenerative capacity of cartilage is very low and once the damage is severe it is difficult to reverse. It starts with pain, followed by limitation of movement, and finally loss of joint function. If the weight-bearing joint is involved, it will cause disability and joint replacement is required to improve the motor function. For the treatment of osteoarthritis, there are 3 misconceptions that need to be corrected first.
1. Not everyone over the age of 40 or 50 will develop osteoarthritis. Although aging is one of the most important causes of osteoarthritis, not every older person has symptoms of osteoarthritis, and it has a number of other possible causes, such as trauma, physical labor and overuse, obesity, genetic factors, hormonal changes, etc. To eliminate or avoid causative factors, such as proper rest, weight loss, avoiding mechanical injuries, wearing flexible sports shoes, using appropriate insoles, using canes or wearing knee pads, waist guards and other aids to reduce the load on the affected joints, and carrying out relevant muscle exercises to increase joint stability, etc.
2, osteoarthritis is drug-free. The treatment of osteoarthritis has made great progress, active treatment can not only improve joint function, some patients can even appear radiological improvement.
3, x-ray bone flab formation is directly related to the severity of the disease. There are many clinical patients with x-ray changes, but no joint symptoms, called radiological osteoarthritis, and no treatment is necessary. Special attention should be paid to educating the patient on appropriate activities to maintain joint mobility and muscle strength, and should not be complete rest.
In the past, treatment of osteoarthritis was generally based on symptomatic management, including analgesics, non-steroidal anti-inflammatory drugs and local hormone injections, which saved many patients from pain but could not affect the condition. With the in-depth research on its pathogenesis, it is now mostly advocated that comprehensive treatment should be provided, including.
1, general treatment.
(1) correct daily activity habits and functional exercise of the involved joints.
(2) high calcium diet, prevention and treatment of osteoporosis. As mentioned earlier, the relationship between articular cartilage and the subchondral bone beneath it is like that of a house and its foundation; a strong foundation makes a strong house. Although most patients with osteoarthritis often have increased bone density, recent studies have confirmed that there is a link between the development of osteoarthritis and osteoporosis, with increased age and low calcium intake being common factors in its development. The bone flab around the joint in patients with osteoarthritis arises as a result of local bone overload, i.e., low local relative bone mass, and the occurrence of organic compensation.
Karvonen RL et al. used two- and three-dimensional dual-energy X-ray absorptiometry to examine bone density in the subchondral region of the knee joint in 62 patients with mild knee osteoarthritis and found that regardless of whether the diagnosis of osteoporosis based on spinal bone density Whether the diagnosis of osteoporosis based on spinal BMD was validated or not, there was a significant decrease in BMD in the subchondral region of the joints of the patients. Also, Arden NK et al. found that although patients with osteoarthritis had higher BMD values compared to controls, this did not result in a reduced risk of fracture. Therefore, prevention and treatment of osteoporosis can help prevent and treat osteoarthritis.
2. Symptom control treatment. According to the
3, improve the condition of drugs: the newly emerged drugs to regulate cartilage metabolism, so that people can intervene in the course of their disease and achieve the purpose of changing the condition, such drugs are hyaluronic acid (such as Spironolactone), glucosamine (such as Vibram), TNF-blocker (Ambitin), etc.. Recently, calcitonin (e.g. MIGA) has also been found to have similar effects.
4, In addition to drug treatment, appropriate physical therapy including acupuncture, massage, massage and medical sports, especially tai chi, are helpful for the relief of osteoarthritis symptoms.