Osteoarthritis of the knee

Thai society is transitioning into a bona fide aging society. The population life expectancy is trending upwards, and the same holds true for the increasing propensity of knee osteoarthritis.

When we talk about "osteoarthritis," the first thing we should focus on is the "articular cartilage" of the joints. Its role and function are to facilitate smooth, continuous motion of the joint. The articular surface at the ends of the bones must have unique properties and characteristics. It must be glossy, smooth, and viscoelastic, enabling it to withstand dynamic weight loading on the joint surfaces. The joints are also lubricated to help reduce friction during movement.

The degenerative part of knee osteoarthritis is the "articular cartilage." In the elderly, the knee joint has been subjected to walking, moving, bending, and stretching for a long time. The repeated impacts on the knee joint induce changes within the articular cartilage with less flexibility and increased brittleness, causing articular cartilage breakage and peeling, exposing the rigid, rough, and inflexible bone layer beneath that is not designed to support the joint movements. The hard bones will rub against each other with knee motion, causing pain, inflammation, and swelling like an engine without lubricant.

Risk factors of knee osteoarthritis

There are two types of risk factors for osteoarthritis:

Unchangeable risk factors such as age, being female, or genetic factors
Modifiable factors are accidents causing injuries to the joint surface, an occupation requiring repeated knee bending, heavy body weight, weak thigh muscles, and metabolic syndrome.

Modifiable factors are of interest because if we can stay clear of them, the likelihood of developing osteoarthritis will be less.

Symptoms

The symptoms of knee osteoarthritis vary depending on the severity and the underlying pathology. The main symptoms that lead to a visit to a doctor can be categorized into three groups, as follows:

Pain - The pain is chronic within the knee joint. It is related to walking and the way you work it. Sitting still will not hurt. With moving, there may be a rustling sound caused by the friction of rigid bones—the more severe the symptoms of osteoarthritis, the greater the pain.
Dysfunction - It hurts to walk or sit for a long time; when you get up, you can't walk immediately. You must establish a foothold before starting to walk.
Deformity - In severe cases, the articular cartilage is completely gone, and when the hard bones rub against each other for a long time, it will cause the bone to grow. Bones that have collapsed will deform into many forms, such as bent knees, cymbal knees, or cannot fully extend knees.

How do doctors diagnose knee osteoarthritis?

In general, a diagnosis is made from medical history, physical examination, and sometimes knee X-rays to confirm the diagnosis and assess its severity.

Knee X-ray is taken with the patient standing up to apply pressure on the joint surfaces. The doctor will focus on the space between the end of the bones. Since articular cartilage does not contain calcium, it shows up as a dark gap between the ends of the bones on an X-ray image. A narrow dark gap means the articular cartilage at this location has whittled away, allowing the underlying rigid bones to be in contact with each other. If knee osteoarthritis is severe, bones that rub against each other have eroded and can cause misalignment of the knee joint.

Treatment

Treatment options depend on the severity of the osteoarthritis. Non-surgical treatment includes providing information, weight loss, and strengthening thigh muscles through exercise. The doctor may prescribe an anti-inflammatory medication to relieve pain symptoms.

However, in patients with severe osteoarthritis, non-surgical treatment is often ineffective. Knee arthroplasty using synthetic knee prosthesis will help the patient free from pain, restore normal knee alignment, regain walking and knee function, and allow the patient a better quality of life.