Stages of Knee Osteoarthritis


Also known as wear-and-tear arthritis, osteoarthritis (OA) occurs when the cartilage (natural cushioning found between the joints) wears away.

When this happens, the joint bones will rub more closely. This rubbing causes swelling, stiffness, pain, decreased movement ability, and in some instances, the formation of bone spurs.

Osteoarthritis is considered the most prevalent type of arthritis.

While the condition can also develop in young people, the chance of developing osteoarthritis becomes relatively higher for those past 45 years of age. Women are also more prone to osteoarthritis compared to men.

Knee Osteoarthritis

Causes and Risk Factors

Most cases of knee osteoarthritis are attributed to age.

However, while most individuals will likely develop some degree of osteoarthritis, several factors can significantly increase the risk of the disease developing at an early age.

Some of the common risk factors include:

  • Heredity – certain genetic mutations can make certain individuals susceptible to knee osteoarthritis. The condition may also result from inherited abnormalities that affect the shape of the bones surrounding the knee joint.
  • Weight – excess weight puts strain and stress on the knees. Every extra pound is equivalent to 3 to 4 pounds of weight on the knees.
  • Repetitive stress injuries – individuals engaged in work that involves repetitive activities that can cause joint stress (squatting, kneeling, lifting weights, etc.) are more likely to develop the condition.

Different Stages of Knee OA

Osteoarthritis has five stages: stage 0 is for normal and healthy knees while stage 4 is for severe cases.

Stage 0

The knee joint for stage 0 shows no indications of osteoarthritis. The joint also functions without any pain or impairment.

Stage 1

An individual with stage 1 OA  may already have bone spur growth (although very minor). The boney growths that develop where the bones meet each other are called bone spurs.

Also, it is unlikely for persons with stage 1 OA to experience any discomfort or pain as the wear on the joint components are still very minimal.

Stage 2

People diagnosed with stage 2 OA are considered to have a “mild” degree of the condition. While X-rays might show greater bone spur growth, the cartilage is most likely still at a healthy size.

Also, there is still normal space between the bones so no bone rubbing or scraping is taking place. The level of synovial fluid present is also sufficient so there are no noticeable changes in the joint motion.

However, stage 2 OA is the usual phase when some symptoms—joint stiffness, tenderness when bending or kneeling, pain after a day of running or walking—will likely manifest.

Stage 3

This stage is also classified as “moderate” OA. This is also the stage where there is notable narrowing of the space between the bones. The cartilage will also show damages.

Individuals with stage 3 knee OA will likely experience frequent pain when kneeling, running, bending, or walking. Joint stiffness may also be felt when sitting for a long time or early in the morning. Joint swelling might also manifest after an extended time of movement.

Stage 4

Stage 4 knee OA is classified as “severe.” People with stage 4 knee OA often feel severe pain and discomfort when moving the joint or walking.

This is also the stage where the cartilage is almost completely gone and the joint space becomes significant.

Patients with stage 4 knee OA will experience severe joint stiffness and may even find it difficult to move. The synovial fluid is also dramatically decreased and can no longer reduce the friction of the joint’s moving parts.

If you suspect you have knee osteoarthritis, it is recommended that you seek medical attention right away. Visiting your doctor is imperative even in the early stages so the condition will be remedied before it escalates.

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