Why is my knee in pain?
The most common cause of knee pain in older patients is Osteoarthritis of the knee. This means that the cartilage over the knee joint is worn out and destroyed. This is also known as degeneration of the knee and can cause severe limitation in knee function.
It is estimated that up to 40% of patients above the age of 50 have knee osteoarthritis. Osteoarthritis is not limited to the knee joint and can occur in other joints, especially joints in the legs and the spine.
Osteoarthritis can also cause other symptoms such as stiffness of the knee, and weakness of the legs. You may become more prone to falls, and may also find that activities such as stair climbing, walking on slopes or uneven ground, and squatting may become more difficult or even impossible.
How does Osteoarthritis occur?
There are 2 types of osteoarthritis,
Primary – which means that there are multiple factors that contribute to the formation of knee arthritis, with no factor thought to be the most important. This is the most common form of osteoarthritis in the elderly in Singapore.
Secondary – which means that there is one factor that is the most likely cause of knee degeneration. Some examples of secondary osteoarthritis of the knee are,
- Previous infection of the knee joint
- Auto-immune conditions in which the patient’s own body for whatever reason attacks the lining of their own knee joint
- Previous fractures involving the knee joint
How does this occur?
Knee problems in old age are caused by the continual damage and stress on the knee joint. Although Old age does not directly cause damage to the knee joint, an older person is more likely to have sustained more injuries in their lifetime than a younger person.
This together with other factors including body weight and genetics leads to the accumulation of irreversible damage to the knee, which triggers a vicious cycle leading to the eventual breakdown of knee cartilage, menisci, and ligaments within the knee.
How do doctors diagnose the cause of Knee pain?
Doctors can diagnose the cause of knee pain through a combination of clinical evaluation, Imaging tests, and Laboratory Tests.
Clinical evaluation
During clinical evaluation, your doctor will:
- Interview you to ask about your symptoms and disabilities
- Check your knee for any swelling, pain, tenderness, warmth
Check the alignment of the knee to see if you are knock-kneed or bow-legged
Imaging tests
In some cases, your doctor might suggest tests such as:
a. X-ray
This is the most important test for diagnosing osteoarthritis. A long leg X-ray may also be taken to check the alignment of your knee.
b. MRI scan for Bone Marrow Lesions (BML)
MRI scan is sometimes necessary if your knee pain is more severe than what the X-rays suggest. MRI scans can look for other causes of knee pain, such as meniscus tears, and may also uncover Bone Marrow Lesions (BML).
BML represents an area of swelling within the bone under the cartilage, and is thought to represent an earlier stage of knee arthritis, and can cause severe pain in the knee. Early identification of BML will allow early treatment and will lessen pain and discomfort considerably.
c. Lab tests
Blood tests are useful to identify other causes of knee pain in the elderly, such as gout and septic arthritis. Septic arthritis is a severe infection of the knee joint and can cause severe pain.
In patients with severe swelling of the knee, your doctor will usually offer to remove the fluid within the knee. This serves 2 functions, firstly, it relieves pain in the knee joint, secondly, it allows testing of the fluid removed, which may point to other causes of knee pain in older patients, such as gout or pseudogout.
How does Arthritis impact my lifestyle?
Arthritis, and other conditions with joint pain and stiffness can become severe enough to make daily tasks difficult. Arthritis of the knee can affect activities like prolonged walking, climbing stairs, and squatting, making them more difficult or impossible. This affects the quality of life of the individual, and may also affect them emotionally and socially.
Can we slow this down?
The evidence is currently evolving, and there is much we do not understand about osteoarthritis. While there is currently no reliable way to delay the onset of arthritis, there are ways to mitigate the effects of osteoarthritis, to allow the individual to continue to lead fruitful lives.
These include the principles of general health, such as the maintenance of healthy body weight and regular exercise. Regular moderate exercise, in particular, has a positive effect on the health of cartilage cells and should be considered an integral part of maintaining knee health in older individuals.
There is some recent evidence that also suggests that irreversible muscle loss as a result of inactivity, a condition known as sarcopenia, is bad for the health of knee cartilage, and can lead to more severe osteoarthritis of the knee.
For an assessment of your condition, please book an appointment with Dr. Yong Ren.
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