Understanding Knee Osteoarthritis

Knee osteoarthritis (OA) is a common condition that can cause pain and stiffness in your knee joint.

Imagine your knee joint as a smooth, gliding door. The cartilage acts like the slippery, yet compressive lining, keeping everything moving effortlessly. In OA, this cartilage can deteriorate, resulting in thinning or small gaps in the coverage of the cartilage. Cartilage has no nerve supply, so it doesn’t cause pain itself, but the other tissues within this unhappy joint can cause the symptoms you may experience. These are some classic symptoms of OA:

• Pain: A dull ache or sharp pain, often worse with activity or after periods of rest (like that morning stiffness you might experience).
• Stiffness: Difficulty bending and straightening your knee, especially first thing in the morning.
• Reduced Mobility: Difficulty with activities like walking, climbing stairs, or kneeling.
• Grinding or Clicking: Sometimes, you might hear a grinding or clicking sensation as your knee moves.

Yes, age and sex (being female) are risk factors, but OA isn’t just a wear-and-tear condition. Injuries, repetitive stress, obesity, and even genetics can all play a role.

In good news, diagnosis of knee OA doesn’t require fancy tests. Physiotherapists and General Practitioners can diagnose OA based on:

• Your Symptoms: We’ll ask about your pain, stiffness, and functional limitations.
• Physical Examination: We’ll assess your range of motion, joint tenderness, and swelling.
• X-rays (Optional): X-rays don’t predict the function of the person in the scan. While some features of OA can be visualised on X-ray, there can be a significant range in pain experiences from low pain in a historically advanced looking scan, to high pain experience in a scan that might not show features of OA change. 

Remember, early diagnosis and intervention are key to managing OA and maintaining an active lifestyle. Getting good, long lasting advice can save you thousands in the long term if you are able to act early. 

Author: Sam Donaldson
M Phty (Sports), BAppSci (HMS)
APA Sports & Exercise Physiotherapist

Updated: 5/2/26

Sam is an APA Titled Sports and Exercise Physiotherapist and Director of RHP who is passionate about keeping people active, with a special interest in knee injuries across the lifespan, ACL rehabilitation, lower limb injuries, and exercise-based rehab. With dual Masters qualifications and extensive experience in elite sport, he delivers goal-focused, evidence-based care to help patients get back to what they love.