Knee Osteoarthritis

What is knee osteoarthritis?

Osteoarthritis of the knee happens when the cartilage in your knee joint breaks down, causing the bones to rub together. This friction causes pain and swelling in your knee, leading to stiffness. Osteoarthritis is a degenerative joint disease — a product of wear and tear over time. It’s very common, and the knee, which takes a lot of stress over your lifetime, is one of the most common joints affected.

Osteoarthritis (OA) in your knee is a long-term, progressive condition with no cure. There are many treatments available to slow its progress and ease your symptoms, and lifestyle changes can help. But it does tend to worsen with time, and it can eventually lead to disability. Your healthcare provider will monitor your arthritis as it progresses. When it starts to really impact your life, surgery is an option.

Stages of knee osteoarthritis

While there aren’t definitive stages of osteoarthritis in your knee, it is a degenerative condition that progresses in a predictable way. (This is different from other types of arthritis in your knee.) Your healthcare provider might use stages or levels to explain how advanced your condition is. Understanding how osteoarthritis progresses can help you understand your symptoms and what to expect next.

Stages include:

• Stage 1 (Minor). Stage 1 means that you’ve got some wear and tear in the cartilage in your knee joint. You probably haven’t noticed any pain yet.
• Stage 2 (Mild). The mild stage is when you might start to feel pain and stiffness in your knee joint, but there’s still enough cartilage to keep the bones from grinding together.
• Stage 3 (Moderate). If you’re at the moderate stage, your cartilage has significantly reduced. This causes more pain, especially when running, walking, squatting and kneeling. You might also have more stiffness or difficulty moving your joint, especially after long periods of inactivity.
• Stage 4 (Severe). Severe knee osteoarthritis means that the cartilage in your knee is almost gone, leaving the bones to grind against each other when they move. Your knee is stiff, painful and possibly immobile. At this stage, you might consider knee joint replacement surgery.

Symptoms of osteoarthritis of the knee

Knee pain is the most common symptom of knee osteoarthritis. Your knee might hurt when you put pressure on it, when you move it or even when you’re sitting still. Other OA knee symptoms include:

• Your knee feels stiff, especially after you first get up or you’ve been sitting for a long time.
• Your knee is swollen or feels puffy.
• You hear a cracking or grinding noise when you move your knee.
• Your knee feels wobbly, as if it could buckle or “give out."
• Your knee locks up or feels like it’s stuck when you try to move it.

Possible complications of knee osteoarthritis

As knee arthritis progresses, it can cause some additional negative side effects, including:

• Joint instability. As you start to use your knees less, the muscles that support it can become weaker, making the joint less stable. This can affect how you walk and raise your risk of injury.
• Bone spurs. Loss of cartilage in your joint and friction on your bones can cause bony lumps called bone spurs to grow on them. These can cause more friction and irritation in your joint.
• Baker’s cyst. When the synovial membrane that lines your joint capsule bulges through a tear in the capsule, it traps joint fluid in the bulge, forming a cyst at the back of your knee joint.
• Mood disorders. Having OA can raise your risk of anxiety and depression. New limitations, mobility challenges and chronic pain can all contribute. Your mood can also make these worse.

Osteoarthritis in your knee causes

Osteoarthritis of the knee happens when the cartilage in your knee joint wears down. Cartilage covers the ends of your bones where they meet in your knee joint. It provides padding that allows the bones to move smoothly against each other. It also absorbs shock when you put weight on your knee. When cartilage breaks down, it can’t grow back. As you lose it, you start to lose mobility in your joint.

OA is usually just the result of gradual wear and tear on your joint over time. Sometimes secondary factors, like an injury or extra stress on your knees, contribute to wearing them down sooner. The cartilage in your knees is like your car’s shock absorber, protecting your car from bumps and jolts. If you drive on rough roads, your shocks wear out faster. If you drive on smooth roads, your shocks last longer.

Risk factors of knee osteoarthritis

You might be more likely to develop OA in your knee if:

• You have a body mass index (BMI) of 30 or more (overweight)
• You injure your knee or have an old knee injury
• You frequently put stress on your knee at your job or playing sports
• You inherited a tendency to develop osteoarthritis of the knee
• You have crooked bones or joints, such as having “knock knees”

How doctors diagnose osteoarthritis of the knee

Your healthcare provider will start by asking about your symptoms and physically examining your knee. They’ll check:

• If your knee is discolored, swollen or sore
• If you feel pain in a specific location on your knee
• If there’s any sign you may have injured your knee
• How much you can move your knee (range of motion)
• If your knee joint feels “loose” or unstable
• How you walk on your knee

They’ll follow up with imaging tests. Usually, a knee X-ray will show evidence of knee osteoarthritis. In some cases, they might order an MRI or CT scan if they need to look more closely at tissues in your joint.

What is osteoarthritis of the knee treatment?

Knee osteoarthritis treatments include lifestyle changes, nonsurgical treatments and surgery. Typically, healthcare providers try nonsurgical treatments first before recommending surgery for knee OA.

Nonsurgical treatments for knee OA

Nonsurgical osteoarthritis of the knee treatments include:

• Using pain medications
• Doing physical therapy
• Sometimes losing weight
• Using a knee brace
• Cortisone (steroid) injections
• Knee gel shots (viscosupplementation)
• Genicular nerve block injections
• Platelet-rich plasma injections

Surgical treatments for knee OA

Surgical osteoarthritis of the knee treatments include:

• Cartilage replacement
• Knee bone reshaping (osteotomy)
• Partial knee replacement
• Total knee replacement

Can I prevent osteoarthritis of the knee?

Since there’s usually no single cause of knee osteoarthritis, you can’t entirely prevent it. But you can reduce your risk by reducing stress and strain on your knee joint where possible. For example:

• If your job puts strain on your knees, consider ways to modify how you do it.
• If you jog or run, seek out soft surfaces rather than pavement.
• Vary your fitness routine with low-impact exercises like swimming or cycling.
• If you carry extra weight, losing just 10% of it can significantly reduce your risk of knee OA.