Knee Osteoarthritis: What It Is and Why Exercise Is Your Best Treatment

Knee osteoarthritis is one of the most common diagnoses in adults over 50 in Australia. Specific, supervised movement, designed for your joint and your current capacity, is the most effective non-drug treatment for knee osteoarthritis.

Here is what the evidence says, and what that means in practice.

What is knee osteoarthritis?

Knee osteoarthritis (OA) is a degenerative joint condition that affects the whole joint, not just the cartilage. That includes the bone, cartilage, ligaments, and surrounding muscles.

Over time, several changes occur in the joint:

• The tissue around the joint becomes inflamed
• The articular cartilage (the cushioning layer that allows smooth movement between bones) becomes damaged
• Osteophytes form, which are bony spurs or lumps that develop around the edges of the joint
• The surrounding ligaments and tendons deteriorate

The primary demographic for knee OA is people over 65, but not everyone develops symptoms. The experience of knee OA varies considerably from person to person.

What causes knee osteoarthritis?

There are several established risk factors:

• Previous injury: fractures, dislocations, ligament tears, or meniscal injuries around the knee
• Occupational loading: jobs that involve prolonged kneeling, climbing, or squatting
• Being overweight: a well-established risk factor for both the development and progression of knee OA
• Age: OA is a natural consequence of ageing, though not an inevitable one

Why movement is the treatment

When a joint hurts, the instinct is to reduce movement. Doing so weakens the muscles that support the joint, which transfers more load through the joint itself and increases pain and stiffness.

Two phrases capture this well:

• “Motion is lotion”: movement lubricates the joint and reduces stiffness
• “Bend and mend”: carefully loaded movement helps the joint adapt and recover

“Bone on bone” and “wear and tear” can sometimes be misinterpreted as a joint that is beyond help. But structural damage and pain don’t map directly. Some people have significant cartilage loss and minimal pain; others have moderate changes and significant pain. Pain in knee OA depends on how load is distributed through the joint, muscle strength, inflammation levels, and nervous system sensitisation, not just what shows on a scan. Exercise addresses all of those. It doesn’t reverse structural changes, but it reliably reduces pain and improves function.

What does exercise do for a knee with OA?

Supervised exercise is the most effective non-drug treatment for reducing pain and improving functional movement in knee osteoarthritis. It can:

• Reduce pain responses
• Increase muscle strength, particularly in the thigh, hip, and calf muscles that support and stabilise the knee
• Improve joint mobility
• Improve balance and reduce fall risk
• Prevent deconditioning (the loss of fitness and muscle mass that comes with reduced activity)
• Reduce or maintain weight, which decreases the load on the joint
• Improve your ability to complete daily tasks, and support better sleep and mood
• Reduce sedentary behaviour, which is independently associated with increased fall risk

Water-based exercise can be a useful starting point, particularly for people who are overweight or finding land-based movement painful. It reduces load on the joint while still allowing meaningful muscle work and range of motion. It can be used before progressing to land-based exercise, or alongside it.

How an Accredited Exercise Physiologist can help

An Accredited Exercise Physiologist (AEP) designs exercise programs that are evidence-based and tailored to your specific condition, capacity, and goals. For knee OA, this means:

• Identifying which muscles need strengthening to better support the joint and targeting those specifically. The thigh, hip, and calf muscles each play a role in how load is distributed through the knee.
• Progressing your program safely. Some discomfort in the affected joint during or after exercise is normal, but a significant increase in pain or swelling is a signal that the program needs adjustment.
• Looking at the whole picture: how your knee loads during everyday movements like walking, climbing stairs, or rising from a chair, and whether movement patterns need correction.

One important note: arthroscopy (keyhole surgery) is not recommended as a treatment for knee OA. Joint replacement remains available as a last resort where symptoms can no longer be managed with other approaches, but many people find that a well-designed exercise program significantly reduces or removes the need for that conversation.

What you can do now

• Begin a new activity program slowly and progress gradually under the guidance of an AEP
• If you are overweight, losing 5 to 10% of your body weight can meaningfully reduce pain and improve the outcomes of your exercise program
• Consider water-based exercise as a starting point if land-based movement is currently too uncomfortable
• Assistive devices such as knee braces, walking sticks, and orthopaedic shoe insoles can support your movement while you build strength
• Exercise can relieve symptoms as effectively as pain medication, and with a better safety profile. It works best when it is structured and guided.

Bodytrack’s Accredited Exercise Physiologists work with people at every stage of knee osteoarthritis, from early-stage stiffness to more advanced symptoms. Chronic health conditions may be eligible for referral under Medicare’s GP Chronic Condition Management Plan and Private health fund eligibility may apply.

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Sources

• Arthritis Australia, Osteoarthritis: prevalence, and exercise as first-line management
• Australian Institute of Health and Welfare, Osteoarthritis: how common it is in Australian adults
• Services Australia, GP Chronic Condition Management Plan: Medicare eligibility for allied health referral