Osteoarthritis (OA) is an all-round, multi-level, chronic inflammatory disease with varying degrees of clinical manifestations, centered on degenerative changes in articular cartilage, involving subchondral bone, synovium, joint capsule, and periarticular ligaments and muscles, etc. OA is more common in middle-aged and elderly patients, with more women than men. The prevalence of OA is up to 50% in people over 60 years of age and up to 80% in people aged 75 years. The disease can be as high as 53% of the disability rate. OA is more likely to occur in joints with high load, more activities, the most commonly affected joints for the knee (about 6% of adults) and hip (about 3%); the spine (cervical and lumbar spine), elbow, shoulder, ankle, hand and other joints can also develop.
OA can be divided into two categories according to the causative factors: primary and secondary. Secondary OA is associated with congenital anomalies, joint trauma, inflammation, joint deformities, abnormal force lines, uneven joint surfaces, joint instability and chronic repetitive cumulative strain injury, and can occur at any age. Primary OA mostly occurs in middle-aged and elderly people, without clear systemic or local triggers. Risk factors associated with primary OA include obesity, genetic factors, hormonal and metabolic disorders, etc.
The main pathological features of osteoarthritis are the loss of hyaline cartilage and the reaction of subchondral bone. The changes in cartilage and subchondral bone are mainly degenerative wear, osteosclerosis, cystic changes, bone redundancy formation, and joint hypertrophy and deformation. The cartilage in the load-bearing area has a rough, yellow, and lusterless surface, and its elasticity decreases, gradually becoming thinner and more fragmented, falling out of the joint cavity and forming free bodies. Synovial membrane lesions manifest as secondary synovitis. In the early stages, there are no significant changes in the synovium. As the lesion progresses, the synovium and joint capsule become congested, edematous, hyperplastic, hypertrophic, and have increased synovial fluid due to the stimulation of shed cartilage fragments, resulting in secondary synovitis. The synovium becomes hyperplastic, thickened, and villous due to engulfment of embedded cartilage fragments, resulting in synovial chondromas, which are shed to form joint free-form. This inflammatory change in the synovium is associated with an autoimmune response caused by cartilage damage. The impaired blood circulation in the synovium and the release of synovial cell lysosomal enzymes alter the composition of the synovial fluid, which in turn accelerates the degenerative changes in the articular cartilage. As the lesion progresses, the joint capsule and periarticular ligaments become fibrotic and contracted.
Clinical manifestations of osteoarthritis The main clinical manifestations are joint pain, swelling, deformity and resulting functional impairment. Initially, the pain is mild or moderate with intermittent occult pain, and rarely severe. The pain is mostly dull, accompanied by a feeling of heaviness, soreness and swelling, and bruising, which is aggravated by activity and improves at rest. The pain is mostly related to temperature, air pressure, environment, and emotion, and is aggravated in autumn and winter and on cloudy days. The location of the pain is variable and often changes, mostly between the patella and femur or around the femoral condyles, and on the medial side of the knee. The pain of osteoarthritis is characterized by the following features: ① Pain from activity The knee joint is in a stationary position for a long time, and the pain is relieved when the position is changed at first, and then aggravated when weight-bearing and activity are increased; ② Pain from weight-bearing Pain when going up and down stairs, going up and down slopes, or when standing up from a sitting or squatting position, or knee pain when pulling children or lifting heavy objects. The knee does not hurt when swimming or riding a bicycle; ③ Rest pain The knee joint hurts when it is in a static position for a long time or when sleeping at night, also known as rest pain. It is often relieved by frequent changes of position; ④ Active pain Active muscle contraction increases the burden on the joint and produces pain. In the late stage, the pain may be persistent or nocturnal. There is localized pressure pain in the joint, especially when there is swelling in the joint. There is stiffness and tightness in the joints when waking up in the morning or when standing up after sitting for a long time, which can be relieved after activity. The stiffness of the joints increases when the air pressure decreases or the humidity of the air increases. The joints of the hands may be significantly enlarged and deformed, and Heberden’s and Bouchard’s nodes may be present. Some knee joints may also be enlarged due to bone formation or joint effusion. Patients may feel a bone rubbing sound or rubbing sensation when moving the knee joint. Pain, muscle atrophy, contracture of the joint capsule and soft tissues of the periarticular ligaments can cause the joint to lead to decreased mobility, weakness, weak legs when walking or joint locking, inability to fully straighten or impaired movement. In later stages, inversion or valgus deformity of the knee joint and flexion contracture may occur. Laboratory tests such as routine blood, protein electrophoresis, immune complexes and serum complement are usually within normal limits. Patients with concomitant synovitis may present with mildly elevated C-reactive protein (CRP) and hematocrit (ESR). Patients with secondary OA may have abnormalities in laboratory tests of the primary disease, asymmetric narrowing of the joint space, subchondral bone sclerosis and/or cystic changes, joint rim hyperplasia and bone growth, or joint effusion of varying degrees, with free bodies or joint deformities in some joints.
Clinically, osteoarthritis of the knee is divided into four stages: (1) the first stage of arthritis, in which the joint is slightly uncomfortable after activity and is accompanied by pain and swelling after increased activity, with no obvious signs of cartilage damage on X-ray or MRI. In the early stage of arthritis, there is obvious pain after more activities, which is reduced after rest. In the progressive stage of osteoarthritis, the cartilage is further damaged, resulting in joint deformity and partial loss of function, narrowing of the joint space, cystic changes of the periarticular bone, and sometimes the appearance of free bodies on X-ray. In the advanced stage of osteoarthritis, bone proliferation, cartilage exfoliation and complete loss of function are observed, and joint deformity is evident, with X-rays showing narrowing of the joint space, severe proliferation, coarsening of the joint, and even collapse of the bone.
On October 12, 2007, the Orthopaedic Branch of the Chinese Medical Association issued the “Guidelines for the diagnosis and treatment of osteoarthritis” to standardize the treatment of OA. The so-called standardized treatment of OA means that clinicians, in the face of different patients, can develop a systematic treatment plan according to the degree of pain, the location of the disease, the duration of the disease and the duration of pain, and correctly select non-pharmacological treatment (including physical therapy, patient education about the disease, etc.), pharmacological treatment (what type of drug treatment) and surgical The treatment methods include
Non-pharmacological conservative treatment
Non-pharmacologic conservative treatment is the most basic form of treatment for OA. Other treatment modalities, including pharmacological treatment and surgical treatment, should be carried out on this basis. This should be the first treatment modality recommended by clinicians for patients with OA who are first-time patients but who do not have severe symptoms. Treatment modalities specifically include.
1, patient disease knowledge education Through good disease knowledge education, so that patients have a correct understanding of the causes of OA, pathological changes and regression, establish self-confidence to overcome the disease, and actively cooperate with doctors. This not only makes the patients eliminate the tension, subjective feeling of pain relief, reduce the number of visits to the hospital, and increase the amount of daily activities, and significantly improve the quality of life.
2.Physical therapy After educating patients about correct disease knowledge, together with appropriate aerobic exercise and muscle strength exercises can not only reduce patients’ pain, but also reduce the amount of pain medication, thus improving the clinical treatment effect. For patients with knee OA, the strength of the quadriceps is particularly important. Previously, we usually thought that quadriceps weakness in OA patients was due to disuse atrophy due to joint pain, but recent studies have found that some people with radiological OA manifestations but without clinical symptoms such as pain still exhibit quadriceps weakness. Therefore, joint instability due to quadriceps weakness may contribute to the onset of OA, rather than just being a result of pain after the onset. There is a view that activity and walking should be reduced.
There is also the view that more activity can smooth out or smooth out the bone spurs. In fact, neither is true. The goal of functional exercise is to maintain a certain level of joint mobility and muscle strength. The best way to exercise is to swim, the buoyancy of the water can reduce the pressure of weight on the joints, so that more vigorous activities can be carried out in the water to reduce weight, so as not to increase joint wear and tear due to excessive exercise, but also due to too little activity and excessive obesity and muscle atrophy.
3, weight loss Weight loss can reduce the load on the joints, thus reducing further wear and tear of the joints. Studies have found that the effect of dieting alone is not as good as the effect of increasing muscle strength through exercise while reducing weight.
Medication
For patients with OA who do not achieve significant results with purely non-pharmacological conservative treatment, medications, including oral medications, topical medications, and intra-articular medications, may be used. The application of analgesic drugs should follow the Chinese Medical Association’s “Guidelines for the diagnosis and treatment of osteoarthritis”.
1. Acetaminophen is recommended by the American Rheumatoid Society as the drug of choice (first-line drug) for OA patients with mild to moderate pain. The analgesic effect of acetaminophen is not significantly different than that of common non-steroidal anti-inflammatory drugs, but it is less expensive and has fewer side effects.
Acetaminophen should be used with caution in patients with chronic liver disease or a history of chronic alcohol consumption. To avoid causing hepatotoxic reactions, its maximum daily dosage should not exceed 4 grams. Acetaminophen prolongs the half-life of the anticoagulant drug warfarin; therefore, prothrombin time should be monitored when the two are used together. Acetaminophen has little effect on the kidneys, and the American Society of Nephrology lists it as the preferred pain medication for patients with renal insufficiency.
2. For OA patients with moderate to severe pain, non-steroidal anti-inflammatory drugs (NSAIDs) are recommended first. The commonly used clinical ones include non-specific COX inhibitors (diclofenac, ibuprofen, naproxen, etc.), propensity COX-2 inhibitors (meloxicam, etc.), and specific COX-2 inhibitors (cibotropic). NSAIDs should be applied with caution due to their risk of causing gastrointestinal bleeding and increased nephrotoxicity. Specific COX-2 inhibitors have a better gastrointestinal safety because they mainly act on COX-2 but not on COX-1; meloxicam has a stronger effect on COX-2 and a weaker effect on COX-1 Meloxicam has a stronger effect on COX-2 and a weaker effect on COX-1, so it also has a better gastrointestinal safety. The nephrotoxicity of NSAIDs is mainly due to the inhibition of renal prostaglandins, which affects the regulation of effective blood flow in the kidney. Nabumetone is converted to inactive metabolites before entering the kidney and, therefore, has less impact on renal function. During the drug selection process, physicians should individualize the medication based on a combination of drug properties and patient conditions.
Risk factors for upper gastrointestinal bleeding from taking NSAIDs drugs include age greater than 65 years, history of upper gastrointestinal ulcers or upper gastrointestinal bleeding, concomitant use of glucocorticoids and anticoagulants, and long-term smoking or alcohol consumption. At no time should two different NSAIDs be used together, as the adverse effects of these drugs are synergistic, and there is no significant increase in the analgesic effect of combining them.The dosage of NSAIDs should be started in small doses and increased to anti-inflammatory levels only if they are not effective.
When a patient with OA has moderate to severe pain and the joint is inflamed (effusion, etc.), the physician may consider giving intra-articular injections of glucocorticoids along with intra-articular aspiration. This method can be used alone or in combination with oral acetaminophen and NSAIDs. The infection rate of joint puncture is very low as long as aseptic operation is strictly performed.
3.For OA patients with severe pain, if the symptoms are not significantly relieved after the above treatment, or if the application of NSAIDs is not suitable, opioids can be applied for pain relief. The main adverse effects of opioid analgesics are nausea, vomiting, vertigo, constipation, etc.
In addition, physicians should consider other treatment options based on the patient’s specific situation, such as the location of the disease, severity of pain, and concomitant disorders. (1) For patients with knee OA who have mild to moderate pain and do not wish to take oral medications, topical medications such as diclofenac sodium or traditional Chinese medicine creams may be considered. (2) For patients at high risk of developing complications such as upper gastrointestinal bleeding, drugs with a high gastrointestinal safety profile should be considered. COX-2 inhibitors should be used with caution in patients with hypertension, congestive heart failure, and renal insufficiency; NSAIDs may also be used in combination with a gastric mucosal protective agent or a proton pump inhibitor to reduce the risk of gastrointestinal bleeding. (3) Intra-articular injection of sodium hyaluronate can also be used to treat patients who are not effectively treated with physiotherapy and acetaminophen, or who are not suitable for NSAIDs and have poor results after application. In terms of pain relief, sodium hyaluronate is not significantly different from oral NSAIDs, but takes effect later. Its adverse effects include mild to moderate redness and pain at the injection site, and individual patients may experience increased joint pain and swelling. (4) For patients with OA who have already started NSAIDs drugs at the time of consultation, if they have not undergone systematic non-pharmacological conservative treatment (such as physical therapy, muscle strength exercises, aerobic training, etc.), they should be instructed to start physical therapy such as muscle strength exercises while continuing to take the drugs, which may reduce the dosage of the drugs. If the patient’s symptoms have been completely relieved, the medication can be discontinued and replaced with physiotherapy alone.
4. Recent clinical and research developments in other treatments: glucosamine sulfate and diacetin, as slow-acting drugs that improve cartilage structure, have been shown to have significant and definite therapeutic effects on osteoarthritis with high safety. Intra-articular injection of sodium vitreous acid can enhance the protective and lubricating effect of synovial fluid, while playing a biomechanical protection and molecular barrier chemical protection to cartilage and synovial membrane, nourishing and repairing articular cartilage and relieving joint pain. It is suitable for the treatment of every stage of osteoarthritis.
Surgical treatment
For patients with persistent joint pain that seriously affects the quality of daily life after the above-mentioned formal non-surgical treatment is ineffective, surgical treatment can be considered. The purpose of surgery is to reduce joint pain, correct deformities, preserve joint function and stability, or restore joint function in severe patients. For knee and hip OA, the most commonly used surgical treatment methods include arthroscopic debridement, high tibial osteotomy, total hip/total knee replacement, etc.
1.Arthroscopic debridement is suitable for patients who are relatively young, have free bodies in the joint, obvious bone redundancy but the articular cartilage surface is still relatively intact, and who cannot adhere to drug treatment because of the poor effect of conservative treatment or the adverse reaction of drugs. The development of arthroscopic technology has increased the chance of early surgical treatment, and the free body or bone superfluous in the joint cavity can be removed under the direct view of the arthroscope, which is less traumatic, less painful, and quicker to recover.
The surgery is less invasive, less painful, quicker recovery, and less impact on joint function, which is becoming more and more popular among patients. The results of the surgery depend on the degree of degeneration of the joint and the age of the patient. The more severe the degeneration and the older the patient, the less effective the procedure will be. It should be noted that arthroplasty is a palliative surgery rather than a radical surgery.
2. High tibial osteotomy is indicated for patients with OA who have osteoarthritis of the knee with a simple medial or lateral unilateral compartment, while the relative lateral compartment remains relatively normal. Osteotomies are particularly useful for the correction of internal and external knee deformities. Proper osteotomy is not only effective, but also has a long duration of efficacy and is particularly suitable for young patients with high activity and mild lesion destruction. The purpose of the procedure is to transfer the line of negative gravity of the lower extremity from the affected interval to a relatively normal interval, but it is not indicated in patients older than 60 years of age, with flexion deformity of the joint and excessive internal and external rotation of the joint. Joint fusion is also a reliable method for a single weight-bearing joint of the lower extremity, mainly in patients with severe joint destruction, who are relatively young and have high activity levels. It is to artificially fuse the severely damaged joints together to make the joints painless, but the function is limited after surgery, and the joints cannot be bent, especially for female patients to perform knee fusion, which will make life extremely inconvenient, so this surgery is not done as a last resort.
3, artificial joint replacement for the treatment of osteoarthritis in the past 20 years has made rapid progress. Now both material science, prosthesis design, production process and surgical techniques have reached a fairly mature stage. Artificial joint technology, particularly hip and knee arthroplasty, is now considered to be a very definite treatment. Arthroplasty can be considered for patients with persistent severe pain, radiologically significant degeneration, and age 60 years or older with OA. Compared to other treatment outcomes, the long-term results are ideal, although the one-time cost is high. The age of the patient can be relaxed as the results of the surgery continue to improve. The outcome of artificial joint replacement is directly related to the timing of surgery, the experience of the surgeon, the overall condition of the hospital, the patient’s preoperative physical condition, the perioperative management and the postoperative rehabilitation. The success rate of 20 years for artificial hip joints and 15 years for artificial knee joints is more than 90%.