Knee Osteoarthritis
Knee osteoarthritis is a degenerative condition where knee joint cartilage gradually wears down, causing pain, stiffness, swelling, and reduced movement. It usually develops over time due to ageing, past injury, excess weight, overuse, or genetic factors. Symptoms often worsen with activity and improve with rest, and treatment focuses on exercise therapy and pain control, with surgery considered in advanced cases.
Overview | Symptoms & Causes | Diagnosis | Treatment Options
The Knee Joint
The knee joint is where the thigh bone (femur), shin bone (tibia), and kneecap (patella) meet. The ends of these bones are covered with smooth articular cartilage, which allows the joint to move freely without friction. Surrounding ligaments, tendons, and muscles provide stability and support, while a thin membrane called the synovium produces lubricating fluid to keep the joint moving comfortably.
Knee osteoarthritis (OA) is a degenerative joint condition in which the protective cartilage gradually breaks down. As the cartilage thins, the joint becomes less smooth and the bones begin to grind against each other, leading to stiffness, pain, and reduced mobility. Over time, the body may form bony spurs (osteophytes), the joint space narrows, and inflammation can develop, further contributing to discomfort.
It is a progressive condition, but symptoms vary widely - some people experience only mild stiffness, while others develop more persistent pain and functional limitations.
Understanding Knee Osteoarthritis
Knee osteoarthritis develops gradually, and symptoms often worsen over time. Many people notice stiffness or discomfort at first, which can progress to more persistent pain or mobility problems. Symptoms may fluctuate - good days and bad days are common.
Common features include:
- Knee pain: Often described as a deep, aching pain inside the joint. It may worsen with activity (walking, climbing stairs, standing for long periods) and improve with rest. Some people feel pain after inactivity, such as when first standing up after sitting.
- Stiffness: Most noticeable in the morning or after sitting still. Stiffness usually improves once the knee “warms up,” but may return later in the day.
- Swelling: The knee can become puffy or enlarged due to inflammation or excess joint fluid. This may come and go.
- Reduced movement: Pain, stiffness, and structural changes can limit how far the knee can bend or straighten.
- Grinding or clicking (crepitus): A sensation of crackling, grating, or clicking when moving the knee, caused by roughened cartilage surfaces.
- Weakness or instability: The knee may feel as though it could “give way,” often due to reduced strength in the surrounding muscles or altered joint mechanics.
Causes and Risk Factors
Knee osteoarthritis develops due to a combination of mechanical stress, biological changes, and individual predispositions. While ageing and joint wear are major contributors, several lifestyle, anatomical, and metabolic factors can increase the likelihood of developing the condition.
| Ageing | Natural cartilage wear makes OA more common with increasing age. |
| Previous knee injury | Damage from fractures, ligament tears, or meniscal injuries increases long-term joint stress. |
| Repetitive or heavy joint loading | Occupations or sports involving kneeling, lifting, or high-impact activity can strain the joint. |
| Excess body weight | Extra load on the knee accelerates cartilage breakdown. |
| Family history | Inherited traits can influence cartilage strength and joint alignment. |
| Sex | OA is more common in women, especially after menopause. |
| Metabolic conditions | Diabetes and metabolic syndrome may promote inflammation and cartilage degeneration. |
Diagnosing Knee Osteoarthritis
Diagnosing knee osteoarthritis involves a combination of understanding your symptoms, examining the joint, and using imaging to assess the condition of the bones and cartilage. The goal is to confirm the presence of osteoarthritis, determine its severity, and rule out other causes of knee pain.
A clinician will begin by asking about the nature of your knee pain: when it started, what makes it better or worse, and how it affects your daily activities. They will examine the knee for tenderness, swelling, reduced movement, and signs of instability. They may also look at your walking pattern and assess surrounding muscle strength.
| X-Ray | This is the primary imaging test for diagnosing osteoarthritis. X-rays can show joint space narrowing (indicating cartilage loss), bone spurs (osteophytes), changes in bone shape, and signs of advanced wear. It helps confirm the diagnosis and grade the severity. |
| Ultrasound | Ultrasound can be useful for assessing the soft tissues around the knee. It can identify inflammation, excess joint fluid, ligament or tendon issues, and guide injections if treatment is needed. While ultrasound doesn’t show cartilage as clearly as an X-ray or MRI, it provides valuable additional information about soft-tissue causes of pain. |
| MRI | MRI gives a detailed view of cartilage, ligaments, menisci, and bone marrow. It’s not routinely required for diagnosing straightforward osteoarthritis but may be recommended if symptoms are unusual, severe, or if another condition (e.g., a meniscal tear) is suspected |
Treatment Options
Management focuses on reducing pain, improving mobility, and slowing progression. Treatment is personalised, depending on symptom severity, lifestyle, and overall health.
Conservative Treatments
| Activity modification | Adjusting high-impact activities, pacing daily tasks, and incorporating low-impact exercises like swimming or cycling can help manage pain without losing fitness. |
| Pain relief | Paracetamol or NSAIDs (such as ibuprofen) can ease pain. Topical anti-inflammatory gels may be helpful with fewer systemic side effects. |
| Physiotherapy | Strengthening the muscles around the knee - especially the quadriceps and glutes - helps support the joint and reduce pain. Physiotherapy can guide tailored exercises to improve flexibility, stability, and walking function. |
| Weight management | If applicable, reducing excess weight decreases the load on the knee joint and can significantly improve symptoms. |
Procedural Options
| Steroid injection | These can reduce inflammation and provide meaningful short-term relief during flare-ups. They’re often guided by ultrasound for accuracy. |
| Hyaluronic acid injection | Used in some cases to improve joint lubrication and reduce pain, though benefits vary between individuals. |
| Surgical options | • Arthroscopy Generally not effective for established osteoarthritis but may be considered if a treatable mechanical issue (like a loose body) is present. • Partial or total knee replacement Reserved for severe, persistent osteoarthritis that significantly affects quality of life and hasn’t improved with conservative treatment. |
Your clinician will work with you to create a personalised plan that aligns with your needs, goals, and level of activity.
How can Lanthorn help?
Knee X-Ray - £70
Useful for evaluating bone changes such as joint space narrowing, osteophytes, or alignment issues. Often the first imaging test for osteoarthritis.
Knee Ultrasound - £300
A non-invasive way to assess soft tissues around the knee, including cartilage, tendons, and ligaments. It can help identify inflammation, fluid, or other changes contributing to symptoms.
Knee MRI - £350
Provides a detailed view of both bone and soft tissues, including cartilage, menisci, and ligaments. Helpful if symptoms are severe or not fully explained by other imaging.
Steroid Injection - £450
Can reduce local inflammation and provide pain relief, often used when symptoms are persistent or flares occur.
Hyaluronic Acid Injection - £550
Supplements joint lubrication and may improve mobility and reduce discomfort in osteoarthritic knees.
PRP Injection - From £750
Platelet-rich plasma is used in certain cases to promote healing of joint tissues, though evidence varies; can be considered when conservative treatments are insufficient.
