Osteoarthritis (OA) is one of the most common joint diseases. It is a chronic joint disease characterized by degeneration and destruction of joint cartilage and osteophytes. The disease is associated with aging, obesity, inflammation, trauma, joint overuse, metabolic disorders and genetics.
OA is more prevalent after middle age and is more common in women than men. The prevalence of the disease is 10-17% in people aged 40 years, 50% in people aged 60 years or older, and up to 80% in people aged 75 years or older. The disease has a certain rate of disability.
This disease is divided into primary OA and secondary OA according to the cause. the former refers to the cause of OA is unknown, and genetic and physical factors have a certain relationship, mostly seen in the middle-aged and elderly; the latter refers to secondary to joint trauma, congenital or genetic diseases, endocrine and metabolic diseases, inflammatory joint disease, endemic joint disease, other bone and joint . Diseases, etc. It is sometimes difficult to distinguish primary OA from secondary OA, and examination and physical examination can help to determine the cause. Imaging tests can help to diagnose secondary OA. The disease is divided into symptomatic OA, which is accompanied by clinical symptoms, and radiological OA, which is accompanied by obvious clinical symptoms of OA, while the latter has no clinical symptoms but only X-ray OA manifestations.
Clinical manifestations
Common symptoms and signs
The disease is common in the knee, hip, hand (distal interphalangeal joint, first carpometacarpal joint), foot (first metatarsophalangeal joint, heel), spine (cervical spine and lumbar spine) and other joints that bear more weight or have more activities.
Joint pain and pressure pain
The most common manifestation of this disease is localized pain and pressure in the joints. The weight-bearing joints and hands are most likely to be involved. The pain is usually mild or moderate and intermittent in the early stages. It improves with rest and worsens with activity. Persistent pain may develop as the disease progresses. It may lead to restriction of movement. There may be localized pressure pain in the joints, which is especially noticeable in the presence of joint swelling. The pain may be worse in cold, wet and rainy weather.
Enlargement of the joint
In the early stages, there is limited swelling around the joint, and as the disease progresses, there may be diffuse swelling of the joint, thickening of the bursa, or fluid accumulation in the joint. In the later stages, bone bulge may be detected in the joint.
Morning stiffness
Patients may experience stiffness in the morning or after a period of rest, which may be relieved after activity. The duration of morning stiffness usually ranges from a few minutes to ten minutes, and rarely exceeds 0.5 hours.
Joint friction sounds (sensation)
Most often seen in the knee joint. Due to the destruction of cartilage and roughness of the joint surface, a bone friction sound (sensation) occurs when the joint is moved.
Restriction of joint movement
Joint weakness and limitation of movement due to joint swelling and pain, reduced movement, muscle atrophy, and soft tissue contracture. It occurs slowly, with early signs of joint immobility. Later, the range of motion of the joint decreases. It may also cause “locking” when moving due to free bodies or cartilage fragments in the joint.
Characteristics of OA in different areas
Hand
The distal interphalangeal joint is the most commonly involved, showing bony enlargement on both sides of the extensor surface of the joint. This is called Heberden’s node. The proximal interphalangeal joint is called Bouchard’s node. It may be associated with mild localized redness, pain, and tenderness of the nodule. Involvement of the first carpometacarpal joint may result in a square hand deformity due to osteophytes at its base and a snake-like deformity due to finger joint hyperplasia and lateral subluxation.
Knee
Knee podoconjunct involvement is most common in clinical practice. Risk factors include obesity, knee trauma and meniscectomy: the main manifestation is knee pain, which is aggravated by activity, more pronounced after descending stairs, and relieved by rest. In severe cases, internal or external knee deformity may occur. The joint is locally swollen, painful and limited in flexion and extension, and most of them have bone friction sounds.
Hip
The hip joint is more commonly involved in men than in women. It is more unilateral than bilateral. The pain is mostly intermittent and dull, but may become persistent as the disease progresses. In some patients, the pain can be radiated to the groin, inner thighs and buttocks. The hip motion is mostly limited by internal and external rotation, followed by internal and external rotation and extension. Gait abnormalities may occur.
Foot
The metatarsophalangeal joints are often involved and may have localized pain, pressure and bony hypertrophy, as well as deformities such as valgus. Bone spurs may develop on the bottom of the foot, causing difficulty in walking.
Spine
The cervical spine is more commonly involved, and the third and fourth vertebrae of the lumbar spine are the most frequent sites. There may be hyperplasia and osteophytes of the vertebral body and posterior synovial joints, causing local pain and stiffness, and corresponding radiological pain and neurological symptoms in the town when the local blood vessels and nerves are compressed. Cervical spine involvement compressing vertebral a basilar artery can cause symptoms of cerebral blood supply deficiency. Intermittent claudication and cauda equina syndrome can occur when lumbar spine osteophytes lead to spinal stenosis.
Ancillary tests
Laboratory tests
Patients with synovitis may have mildly elevated CRP and ESR. Patients with secondary OA may present with abnormalities in narrow laboratory tests of the primary disease. Synovitis may be present with joint effusion. The joint fluid is usually clear, yellowish, and of normal or slightly reduced viscosity, but the mucin is well coagulated. It may show mild leukocytosis with a predominance of single nucleated cells. Synovial fluid analysis can help rule out other joint diseases.
Imaging
Imaging is not only useful to help confirm the diagnosis of OA, but also to assess the severity of joint damage; to evaluate disease progression and response to treatment; and to detect disease or related complications early.
X-rays are routinely performed, and the characteristic radiological findings are
Sclerosis of subchondral bone, subchondral cystic changes and bone formation, and narrowing of the joint space. In severe cases, joint deformation and subluxation. These changes are an important basis for the diagnosis of OA. There is no strict correlation between the severity of radiological manifestations and the severity of clinical symptoms and functional status. Many joints with significant imaging changes do not have typical symptoms, while joints with typical symptoms only have minor imaging changes. Narrowing of the joint space is not only due to a decrease in articular cartilage content, but meniscal damage and cartilage compression are also important causes.
Magnetic resonance imaging is not commonly used and is only useful for detecting joint-related tissue lesions such as cartilage damage, synovial fluid leakage, subchondral bone marrow edema, synovitis and meniscal or ligament damage; it can also be used to rule out tumors and ischemic osteonecrosis.
Ultrasound is helpful in detecting small amounts of joint exudate, synovial proliferation, bony bulges, N-fossa cysts, inflammatory reactions, and also in identifying erosive and non-erosive OA of the hand.