Osteoarthritis is a chronic joint disease characterized by degeneration and destruction of joint cartilage and osteophytes. The disease is more prevalent after middle age. Preliminary domestic surveys show that the overall prevalence of osteoarthritis is about 15%, with a prevalence of 10%-17% in people aged 40 years and 50% in people aged 60 years or older. Among people over the age of 75, 80% suffer from osteoarthritis. The ultimate disability rate of the disease is 53%. Clinically, swollen and painful joints, osteophytes and limited mobility are most common. There are no geographical or racial differences in the development of osteoarthritis. Age, obesity, inflammation, trauma, and genetic factors may be associated with the development of the disease.
[Clinical manifestations]
1.Symptoms and signs
Osteoarthritis mainly manifests as pain, swelling, morning stiffness, joint effusion and bony hypertrophy of the affected joints, which may be accompanied by bone rubbing sound, dysfunction or deformity during activities.
(1) Joint pain and pressure pain
The most common manifestation of this disease is localized pain and pressure pain in the joints. The weight-bearing joints and hands are most likely to be involved. It is usually mild or moderate intermittent pain in the early stage, which improves with rest and worsens with activity. There may be localized pressure pain in the joints, which is especially obvious when accompanied by joint swelling.
(2) Joint swelling In the early stage, there is limited swelling around the joint, but as the disease progresses, there may be diffuse swelling of the joint, bursal thickening or joint effusion. In the later stage, bony swelling around the joint may be detected.
(3) Morning stiffness Patients may experience stiffness and a feeling of adhesion in the morning, which may be relieved by activity. The duration of morning stiffness is relatively short, usually a few minutes to ten minutes, and rarely exceeds half an hour.
(4) Joint friction sounds are mainly seen in osteoarthritis of the knee joint. Due to the destruction of cartilage, the joint surface is rough and there is a bone rubbing sound (sensation) and twisting sensation when the joint is moved, or it is accompanied by local pain in the joint.
2.Osteoarthritis of different parts
(1)Hand
The distal interphalangeal joint is most commonly involved, showing bony enlargement on both sides of the extensor side of the joint, called Heberden’s node. The proximal interphalangeal joint is called Bouchard’s node. It may be accompanied by mild localized redness, swelling, pain, and tenderness of the nodule. When the first carpometacarpal joint is involved, osteophytes at its base may result in square hand deformity, while finger joint hyperplasia and lateral subluxation may result in snake-like deformity.
(2) Knee joint
Knee joint involvement is the most common in clinical practice. Risk factors include obesity, knee trauma, and meniscectomy. The main manifestation is knee pain, which is aggravated by activity and relieved by rest. Severe cases may present with inversion or valgus deformity of the knee.
(3) Hip joint
The involvement of the hip joint is mostly characterized by localized intermittent dull pain, which may become persistent with the development of the disease. In some patients, the pain may radiate to the groin, inner thighs and buttocks. The hip joint movement disorders are mostly in internal rotation and external booth, followed by limitation of internal retraction, external rotation and extension.
(4) Spine
Involvement of the cervical spine is more common. There may be hyperplasia and osteophytes of the vertebrae, intervertebral discs and posterior synovial joints, causing local pain and stiffness, and corresponding radiological pain and neurological symptoms may occur when local blood vessels and nerves are compressed. Involvement of the cervical spine compresses the vertebrobasilar artery, causing symptoms of inadequate blood supply to the brain. Intermittent claudication and cauda equina syndrome can occur when lumbar spine osteophytes lead to spinal stenosis.
(5) Foot The metatarsophalangeal joint is often involved, and in addition to local pain, pressure and bony hypertrophy, deformities such as bunions can occur.
3.Special types of osteoarthritis
(1) Primary generalized osteoarthritis
The distal interphalangeal joint, proximal interphalangeal joint and the first carpometacarpal joint are the preferred sites. Knee, hip, metatarsophalangeal joints and spine may also be involved. Symptoms are episodic and may include effusion and fever in the affected joints. It can be classified into two categories based on clinical and epidemiological factors: (1) the nodular type, which mainly involves the distal interphalangeal joints, is more common in women and has family clusters. The non-nodular type is predominantly involved in the proximal interphalangeal joints and is not characterized by gender or family clustering, but often has recurrent peripheral arthritis. Severely affected patients may have increased sedimentation and increased C-reactive protein.
(2) Erosive inflammatory osteoarthritis
It is common in postmenopausal women and mainly involves the distal and proximal interphalangeal and carpometacarpal joints. There is a familial tendency and recurrent acute attacks. The affected joints are painful and tenderness, eventually leading to deformity and ankylosis. The patient’s synovial examination reveals marked proliferative synovitis with immune complex deposition and vascular opacification. x-ray reveals marked osteophytes and subchondral osteosclerosis, and in advanced stages, marked bone erosion and bony ankylosis of the joint.
(3) Diffuse idiopathic skeletal hyperostosis (DISH)
It occurs in middle-aged and elderly men. The lesion involves the entire spine with diffuse osteophytes and extensive hyperplasia ossification of the spinal ligaments and their adjacent bony cortical hyperplasia. However, the small vertebral joints and intervertebral discs remain intact. X-rays show characteristic calcification of the anterior and posterior longitudinal ligaments of the vertebral body, mainly in the lower thoracic segment, usually with 4 or more consecutive vertebrae, and may be accompanied by extensive osteophytes.
4.Laboratory tests
The indicators of routine blood, protein electrophoresis, immune complexes and serum complement are generally within normal limits. Patients with synovitis may have mildly elevated C-reactive protein and blood sedimentation. Rheumatoid factor and antinuclear antibodies are negative. Patients with secondary osteoarthritis may present with abnormal laboratory tests of the primary disease.
Those presenting with synovitis may have joint effusion; however, the joint fluid is usually clear, yellowish, and of normal or slightly reduced viscosity, but the mucin is well coagulated.
5.X-ray examination
The X-ray features of osteoarthritis are: asymmetrical joint space narrowing; subchondral bone sclerosis and cystic changes; osteophytes and bone redundancy formation at joint edges; intra-articular free bodies; joint deformation and subluxation. These changes are important for the diagnosis of osteoarthritis.
[Key points for diagnosis]
The diagnosis of osteoarthritis is not difficult based on the patient’s clinical manifestations, physical signs and imaging and other auxiliary examinations. At present, the diagnostic criteria of the American College of Rheumatology 1995 (Tables 1-3) are mostly used in China.
Table 1 Classification criteria of osteoarthritis of the hand (clinical criteria)
1. hand pain, soreness, and stiffness for most of the time in the past 1 month
2. ≥2 bony enlarged joints out of 10 interphalangeal joints
3. swelling of ≤2 metacarpophalangeal joints
4. bony enlargement of distal interphalangeal joints >2
5. deformity of ≥1 out of 10 interphalangeal joints
Satisfy 1+2+3+4 or 1+2+3+5 to diagnose osteoarthritis of the hand
Note: The 10 interphalangeal joints are the bilateral second, third distal and proximal interphalangeal joints and the bilateral first carpometacarpal joints.
Table 2 Classification criteria for knee osteoarthritis
Clinical criteria
1. knee pain most of the time in the last 1 month
2. presence of bone friction sounds
3. morning stiffness ≤ 30 min
4. age ≥38 years
5. have bony enlargement
The diagnosis of osteoarthritis of the knee can be made if 1+2+3+4, or 1+2+5 or 1+4+5 are met
Clinical + radiological criteria
1. knee pain most of the time in the last 1 month
2. radiographs show bone fragmentation
3. joint fluid examination consistent with osteoarthritis
4. age ≥ 40 years
5. morning stiffness ≤ 30min
6. bone friction sound
Those who meet 1+2 or 1+3+5+6, or 1+4+5+6 can be diagnosed with osteoarthritis of the knee
Table 3 Classification criteria for osteoarthritis of the hip
Clinical + radiological criteria
1. hip pain most of the time in the last 1 month
2. Blood sedimentation ≤20mm/h
3. Bone formation on X-ray
4. narrowing of hip joint space on X-ray
Hip osteoarthritis can be diagnosed if 1+2+3 or 1+2+4 or 1+3+4 are met
[Treatment]
The goal of treatment is to relieve pain, stop and delay the progression of the disease, and preserve joint function. The treatment plan should be based on the condition of each patient.
1.General treatment
(1) Patient education Make patients understand the principles of treatment, exercise methods, as well as the use of drugs and adverse reactions of the disease.
(2) Physical therapy including heat therapy, hydrotherapy, transcutaneous electrical nerve stimulation, acupuncture, massage and tui-na, traction, etc., all help to reduce pain and relieve joint stiffness.
(3) Reduce joint load and protect joint function
Overloading of the involved joints should be avoided. Patients with knee or hip joint involvement should avoid prolonged standing, kneeling and squatting. Canes and walkers can be used to assist activities, and obese patients should reduce their body weight. Coordinated muscle movement and muscle strength can reduce the painful symptoms of the joint. Therefore, patients should pay attention to strengthen the strength exercise of the muscles around the joint and design exercise programs to maintain the range of motion of the joint.
2.Medication
It can be divided into drugs for symptom control, drugs for improving the condition and cartilage protectors (Table 4-5).
(1) Symptom control drugs
①Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs are the most commonly used class of drugs for the treatment of osteoarthritis (Table 4), and their effects are to reduce pain and swelling and improve joint movement. The main drugs include diclofenac, etc. Selective cyclooxygenase-2 inhibitors such as rofecoxib, celecoxib, and meloxicam are more appropriate if the patient is at a higher risk of NSAID-related gastrointestinal disease. Drug doses should be individualized, with attention to the effect on other comorbid diseases in elderly patients.
Table 4 Commonly used NASIDs for the treatment of osteoarthritis
Propionic acid derivatives Ibuprofen Ketoprofen Loxoprofen
Benzoic acid derivatives Diclofenac
Indolyl acids Sulindole acids Asimethicin
Pyranocarboxylic acids Etodolac
Non-acidic Nabumetone
Ciclosporin Meloxicam
Sulfanilamide Nimesulide
Celecoxib Celecoxib Rofecoxib
Table 5 Drug therapy for patients with osteoarthritis
Oral Acetaminophen
Articular chondroprotective agents Glucosamine sulfate
Selective COX-2 inhibitors
Non-selective NSAIDs + misoprostol or proton pump inhibitors
Other pain relievers Tramadol hydrochloride
Intra-articular injections Glucocorticoids Sodium hyaluronate
Topical topical treatment Diclofenac sodium emulsion Etofenac cream
②Other pain relievers
Acetaminophen has good pain-relieving effect on osteoarthritis and is low in cost, and is still widely used abroad, while its application in China is relatively small. If the above methods are not effective in relieving symptoms, tramadol may be used. The drug is a weak opioid with good tolerability and little addiction. The average dose is 200-300mg per day, but attention should be paid to the adverse effects.
(iii) Topical treatment
It includes local topical NSAIDs drugs and intra-articular injection treatment. Glucocorticoids can relieve pain and reduce exudation, and the effect can last for several weeks to months, but they are only suitable for joint cavity injection treatment, and should not be repeatedly injected in the same joint, and the number of injections should be less than 4 times in a year.
Intra-articular injections of hyaluronic acid preparations (Shinvic, Qisheng, and Spironol) are effective in reducing joint pain, increasing joint mobility, and protecting cartilage, and the therapeutic effect can last for several months.
(2) Improving drugs and chondroprotective agents
These drugs have the effect of reducing the activity of matrix metalloproteinases, collagenases, etc., which can not only anti-inflammatory, pain relief, but also protect the joint cartilage, and have the effect of delaying the development of osteoarthritis. The onset of action is generally slow. The main drugs include glucosamine sulfate, glucosaminoglycan, S-adenosylmethionine and doxycycline. Diacerein may also significantly improve patient symptoms, protect cartilage, and improve the course of the disease.
Cartilage damage in osteoarthritis may be related to the action of oxygen free radicals. Studies in recent years have found that vitamins C, D and E may be beneficial in the treatment of osteoarthritis mainly through their antioxidant mechanism.
3.Surgical treatment
Surgical treatment can be considered for patients with severe lesions and significant joint dysfunction after no significant effect of medical treatment.
(1) Arthroscopic surgery
For patients with obvious joint pain and unsatisfactory results of painkillers and intra-articular glucocorticoid injections, a large amount of intra-articular lavage can be used to remove fibrin, cartilage debris and other impurities, which can reduce the patient’s symptoms. Cartilage debris can also be removed arthroscopically.
(2) Orthopedic surgery
Osteotomy can improve the balance of joint force lines and effectively relieve hip or knee pain. Patients over 60 years of age with progressive osteoarthritis who do not respond well to regular medication may be offered joint replacement, which can significantly reduce pain symptoms and improve joint function.