Rheumatoid arthritis of knee is a common form of inflammatory arthritis occurring throughout the world and in all ethnicity. It is a chronic disease characterized by clinical course of exacerbation and remission. This disease is more common in Europeans and Indians
Causes Of Rheumatoid Arthritis Or Knee
Both environmental and genetic factors play a part.
- more common in homozygous twins
- Genetic predisposition: the disease is strongly associated with hereditary patterns
- Variations in HLA locus of genes
- Infections also trigger rheumatoid arthritis of knee by initiating the autoimmune process inside the body.
- Increased risk with cigarette smoking
- The disease is less severe in pregnancy due to suppression of immune response during pregnancy but hormonal changes may also play an important role
Pathogenesis of Rheumatoid Arthritis of Knee
Rheumatoid arthritis of knee is an autoimmune condition in which the body’s immune system is hyper responsive and producers antibodies against the normal tissue of the body. WBCS and B cells play an important role in the pathogenesis of rheumatoid arthritis. These cells interact with other cells in synovium as a result destroy the Synovial membrane. The inflamed tissue also releases prostaglandins and nitrous oxide which causes dilation of arteries, swelling, and pain inside inflamed synovium.
At the joint margins, the synovium innervates bone and cartilage and forms bone erosions. Later, bone erosions can cause fibrosis and ankylosis. This leads to progressive biochemical and mobility dysfunction and if not treated on time this may further amplify the destruction of joints. The most common site affected is extensor tendons of joint surfaces. Granules may also form in the lungs, heart, and eyes as a result of Rheumatoid arthritis.
Clinical Features Associated With Rheumatoid Arthritis:
Rheumatoid arthritis usually involves small joints but may also cause inflammation of large joints such as knee and ankle joints. Pain is induced over the knee joint during bending, walking, running, and climbing stairs. There is morning stiffness of more than one hour in the knee joint which improves during the day with activity. Sometimes a cyst may develop in patients with knee arthritis in which Synovial fluid for the fluid present in joint space accumulates in the cyst which prevents the normal mechanism of joint function.
This cyst can rupture leading to joint pain and swelling. The joint involvement is more common in males and in older patients with the long standing disease and is less common in adults. Arthritis healed is by medical therapy but aggressive medical therapy and strict patient compliance is required for permanent treatment of rheumatoid arthritis of knee.
The typical presentation with joint involvement is pain swelling and stiffness affecting the small joints of hands and feet. It causes the destruction of joints in a symmetrical fashion. However, large joint involvement, systemic symptoms, and extra articular features may also occur. In old age, rheumatoid arthritis has a sudden onset and is associated with swear pain, inflammation, morning stiffness and involves multiple joints which are also called polyarthritis.
It can also present as polymyalgia rheumatic which mimics proximal muscle pain. there is an ulnar deformity or left-sided deformity of fingers Swan neck deformity in which the fingers become the shape of swans neck, buttonhole deformity, and Z deformity of the thumb.
Rheumatoid nodules may occur which are frequently asymptomatic but sometimes maybe complicated due to the development of infections and ulcerations. Weight-bearing joints develop inflammation of a bursa and the valgus deformity can also be observed. Due to damage to the ankle, the patient usually has flat feet.
Rheumatoid arthritis of knee is associated with systemic features like weight loss, loss of appetite, osteoporosis, and muscle wasting. When Arthritis is chronic in nature it may develop extra articular manifestations, especially in adult males.
Extra articular disease
It may manifest as vasculitis which is inflammation of vessels, skin ulceration, necrosis. Eye involvement leading to visual disturbances, pain, and redness of eyes. cardiac involvement can also occur leading to myocardial infarction and conduction cardiac defects. Lung fibrosis, peripheral neuropathy, CNS symptoms, spinal cord compression, iron deficiency anemia, and blood loss may also occur.
How to Diagnose Rheumatoid Arthritis of Knee?
- Clinical criteria
- Erythrocyte Sedimentation rate
- C reactive protein
- ultrasound of knee joints
- MRI of knee joints
- Rheumatoid factor
- anti citrullinated peptide
- X-ray of knee joint
Tests to monitor drug safety
- full blood count
- urea, creatinine
- liver function tests
- chest X-ray
How to Treat?
The goal of treatment for rheumatoid arthritis is to decrease the inflammation of joints, prevent joint damage, and improve the mobility of patients. This includes both drug therapy and other conservative therapies to improve the lifestyle of the patient.
- Disease modifying anti rheumatic drugs (DMARDS): DMARDS therapy is given in all the patients suffering from rheumatoid arthritis of knee as it decreases the exacerbations of joint inflammation. Initially, prednisolone is given with methotrexate along with Folic acid. if the patient fails to respond then another DMARD should be introduced in the regime.
- Triple therapy: The most effective therapy for treating knee Arthritis which includes methotrexate, sulfasalazine, and hydro chloroquine.
- Biological therapy: If the disease remains active even after introduction of demands biological therapy may be given for one year.
- Conservative management: change in occupation, reduce smoking and caffeine intake, treating infections timely with antibiotics, aerobic exercises, and strength training exercises.
- Surgical management: if rheumatoid arthritis of knee joint fails to respond to medical treatment it or is causing progressive mobility of patient surgery of affected joint can be performed and joint is replaced by synthetic joint.
Complications of Rheumatoid Arthritis of Knee
Rheumatoid arthritis of the knee is a chronic disease involving multiple joints. It is associated with a wide range of complications some of which are
- difficulty in walking
- difficulty in climbing stairs
- difficulty in bending of legs
- cysts behind knee joint
- inflammation of cyst
- infection and bursting of cyst
- chronic pain
- anxiety and depression inpatient due to the chronic course of the disease
When to Seek Medical Help?
If your knee joint is causing severe pain, inflammation, and stiffness is increasing from one hour to more than 5 hours you should seek medical help. Timely administration of medications may help treat disease, prevent complications, and recurrence.