Knee cartilage damage might sound like a complex medical issue, but it’s more common than you think. You may have cartilage damage if you’re experiencing pain, swelling or stiffness in your knee. In this guide, we'll break down the symptoms, causes, and diagnostic methods for knee cartilage damage, including how an MRI scan can help identify the issue early. Whether you’re seeking relief or trying to understand your treatment options, we’ve got clear and practical insights to help you take the next step.
What is Knee Cartilage Damage?
Knee cartilage damage happens when the smooth tissue in the knee joint (articular cartridge) breaks down or gets damaged through injury. It can happen for all sorts of reasons, from sports injuries to repeated stress on the joint or because of underlying conditions, such as osteoarthritis or other joint disorders.
Your knee cartilage is particularly important because it helps your knee move smoothly, absorb shock during exercise and distribute weight evenly. Damage to the cartilage can result in pain, stiffness and difficulty moving the joint or putting weight on it.
What Are the Symptoms of Knee Cartilage Damage?
The symptoms of knee cartilage damage can vary from person to person, but they usually include:
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Pain: You may experience a dull ache or a sharp pain in the knee, especially when putting weight on the joint. The more cartilage damage there is, the more pain you’re likely to experience. Underlying issues and conditions, such as bone marrow lesions or synovitis, can also worsen pain.
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Swelling and stiffness: Swelling happens when the joint gets inflamed from cartilage breakdown, while stiffness is usually worse after periods of inactivity, such as sitting or sleeping. This can make bending or straightening the knee hard, affecting everyday tasks.
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Catching or locking of the knee: You may find that the knee catches or locks up, particularly if there are loose fragments of cartilage floating around in the knee or if you have a meniscal tear. This happens because the joint simply isn’t working smoothly anymore, and unfortunately, it can lead to more damage to the cartilage.
Symptoms also tend to get worse with activities that strain the knee joint, such as bending, squatting, or climbing stairs.
People with serious cartilage damage often find their everyday activities much harder to do, which can lower their quality of life. They may experience emotional issues, such as anxiety or depression.
Can an MRI Scan Detect Knee Cartilage Damage?
An MRI (magnetic resonance imaging) scan is considered the best and most effective way to detect and diagnose knee cartilage damage or loss. It’s much better than traditional X-rays, for example, for looking at soft tissues like cartilage. MRI scans can show the shape, thickness and health of the cartilage in the knee. This helps your doctor spot any issues early on, even if your symptoms are still mild.
Early detection of joint cartilage defects is important because it can help prevent damage from worsening.
What Does Knee Cartilage Damage Look Like on MRI?
MRI scans can reveal areas where the cartilage has become damaged, but it can appear in several ways, depending on how much damage is present.
Early signs of cartilage damage will appear as bright areas on the MRI scan, indicating a softening or a loss of cartilage tissue and structure. If the damage is more significant, changes or irregularities in the signal pattern may be seen in the middle layers of the cartilage.
Severe damage to the cartilage will appear as dark areas on the MRI and extend through the cartilage to the bone itself. Cracks and damage to the cartilage tissue will appear as dark lines or spots, usually in the middle of the joint. That tells your doctor that the joint has long-term wear and tear.
If there are bone marrow lesions, often associated with cartilage degeneration or injury, these will show up as dark or light spots on the MRI, indicating swelling or damage to the bone.
If your doctor needs a more detailed view of the knee’s structures, they may recommend a special MRI technique called an MR arthrogram, which requires a contrast dye to be injected into the knee, highlighting any abnormalities or areas of damage that may not be visible with a standard MRI. Or they may recommend CT arthrography, an imaging technique that combines computed tomography (CT) scans with the injection of contrast dye, if MRI is unsuitable.
How an MRI Scan Detects Knee Cartilage Damage
An MRI scan will detect knee cartilage damage by using a mix of strong magnetic fields and radiofrequency. The scan uses magnets to align water molecules in the body’s tissues, then radiofrequency pulses to disturb the alignment. As the water molecules return to their original state, they give off signals that the computer picks up and processes to create images of the knee.
How Does a Doctor Diagnose Knee Cartilage Damage?
Diagnosing knee cartilage damage involves several steps to assess the extent of the damage and any related joint issues. Here's a breakdown of how your clinician will diagnose knee cartilage damage.
Medical History Review
First, your doctor will begin by reviewing your medical history. This helps them understand your symptoms, any past knee injuries you may have and any activities that you do that may affect the knee. For example, previous injuries like a torn anterior cruciate ligament (an important ligament in the knee) are often linked to cartilage damage.
Physical Examination
Next, your doctor will perform a physical exam to check your knee for signs of swelling, tenderness and how well it moves. If you have any warmth, swelling or difficulty moving, this can point to cartilage damage or other joint problems in the knee.
Range of Motion Assessment
Your doctor will also test how well your knee can bend and straighten. If you experience pain or limited movement, it may be caused by cartilage damage or meniscal tears, or it could be caused by fragments of cartilage causing mechanical blockages. This assessment can help your doctor understand the impact of cartilage damage on your daily activities.
Palpation for Tenderness
Palpation involves your doctor using their hands to feel for areas of tenderness, swelling, or abnormality in the knee joint. Specific areas of tenderness may be a sign of localised cartilage damage or an associated condition such as meniscal tears or synovitis. Byidentifying tender spots, your doctor can understand the extent and location of cartilage damage, which is vital to developing a treatment plan that's right for you.
MRI
MRI is a non-invasive imaging technique that plays a vital role in diagnosing knee cartilage damage. MRI provides detailed images of the knee joint, allowing for the visualisation of cartilage thickness, surface irregularities, and other structural changes. MRI is particularly effective in detecting early signs of cartilage degeneration and associated conditions such as bone marrow lesions and synovitis. MRI findings can help confirm your doctor’s diagnosis and guide their treatment decisions.
X-Ray
While MRI is the gold standard for assessing tough soft tissue structures, X-rays are often used as an initial imaging technique to understand the overall condition of the knee joint. An X-ray can reveal bone structure changes, joint space narrowing and bone spurs (osteophytes), which are a sign of osteoarthritis. However, X-rays are less effective at visualising cartilage damage directly, so they can only be a complementary tool to MRI in the diagnostic process.
Arthroscopy
In some cases, your doctor may recommend arthroscopy to visualise the cartilage and other structures within the knee directly. This procedure involves inserting a small camera into your knee through a tiny cut. It lets your doctor see your cartilage and other knee structures directly, and it's especially useful if earlier tests are unclear.
Gait Analysis
Finally, your doctor will analyse how you walk. Cartilage damage can affect how someone moves, and any changes in your walking patterns can offer your doctor clues about the severity of the damage and how it affects your daily activities.
Causes of Knee Cartilage Damage
There are various causes of knee cartilage damage, each contributing to the cartilage's degradation and the knee joint's overall health. Here are some primary causes of knee cartilage damage.
Osteoarthritis
Osteoarthritis is one of the most common causes of knee cartilage damage. Over time, wear and tear causes the knee cartilage to break down. This leads to changes in the knee joint, such as the growth of bony lumps and damage to the bone underneath. As the condition progresses, the cartilage thins and deteriorates, especially in areas that bear weight.
Meniscal injury
Tears in the meniscus, a cartilage that helps absorb shock in the knee, can harm the knee's overall cartilage health. Damage to the meniscus changes how the knee bears weight, increasing cartilage pressure and speeding up its breakdown. Meniscal injuries are a strong sign of future cartilage loss.
Knee alignment
Problems with how the knee is aligned, such as being bow-legged or knock-kneed, can put uneven stress on the cartilage and cause it to wear out faster. Foot problems like flat feet can also affect how the knee moves, adding more strain to the cartilage
Repetitive stress and overuse
Repeated activities, such as frequent bending or heavy lifting, can damage the knee cartilage over time. Jobs that require a lot of kneeling or squatting are also linked to a higher risk of osteoarthritis and cartilage wear.
Obesity
Carrying extra weight puts more strain on the knee joint, increasing the risk of cartilage damage and osteoarthritis. Obesity also causes inflammation, which can exacerbate joint deterioration.
Previous injuries
Past knee injuries, such as fractures or ligament tears, can make the cartilage more prone to damage. These injuries can change how the knee moves, leading to more pressure on certain areas of the joint. Previous injuries are also linked to a higher chance of developing cartilage damage later.
Inflammation and synovitis
Inflammation in the knee joint can contribute to cartilage damage and break down the components of the cartilage, causing it to wear away faster.
Age-related changes
As people age, the cartilage in their knees naturally weakens. Changes in the cartilage’s structure make it less able to handle pressure, increasing the risk of damage and osteoarthritis. This natural ageing process is a key factor in cartilage breakdown.
Prognosis and Treatment
The prognosis and outlook for knee cartilage damage depends on various factors, including the extent of the damage, the underlying cause, age, activity levels and overall health.
For example, severe cartilage damage is often associated with a poorer prognosis, as it can lead to more significant joint dysfunction and pain. Underlying conditions, such as osteoarthritis, can also complicate the prognosis for knee cartilage damage. Patients with OA often experience a decline in cartilage health, which can lead to more pain and limited mobility.
Age and activities are also important factors. Older adults generally have a higher prevalence of cartilage degeneration due to age-related changes in the cartilage. People who enjoy high-impact activities or engage in activities that involve a lot of knee bending, such as gardening, may experience a faster rate of cartilage wear.
There are different ways to treat knee cartilage damage, from simple home care to surgery. The best approach depends on the extent of the damage, its cause, and your overall health and activity level.
Treatment may include:
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Physiotherapy can strengthen the muscles around your knee, improve movement, and ease pain. It also helps keep the joint working well and slows further damage.
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Painkillers like ibuprofen can reduce pain and swelling, or steroid injections can offer short-term relief from severe inflammation.
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If you're overweight, losing weight can reduce strain on your knee, which helps with pain and slows down cartilage damage.
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Certain injections, such as hyaluronic acid injections, can help relieve symptoms without surgery, which help lubricate the joint, smooth movement, and reduce pain. Another type of injection is platelet-rich plasma (PRP). This uses a concentration of your own blood to help the knee heal and reduce inflammation.
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If other treatments don't work, your doctor may recommend a surgical intervention, like arthroscopy. This involves inserting a small camera into the knee and cleaning out damaged tissue or encouraging cartilage to grow back by creating tiny holes in the bone. Another procedure involves moving healthy cartilage from one part of your knee to the damaged area - this works well for larger patches of damage. Doctors can also take some of your cartilage cells, grow them in a lab and put them back into the damaged area to help it heal. For severe damage, part or all of the knee joint may have to be replaced with an artificial one. However, this can greatly reduce pain and improve movement.
While some of these treatments may sound complex and worrying, be reassured that many people start with simple options like physiotherapy or medications before considering more advanced options such as surgery.
Why an MRI Scan is a Good Option
An MRI of the knee is typically performed to diagnose or evaluate issues such as knee pain, weakness, swelling, or bleeding in the joint tissues, as well as damage to cartilage, meniscus, ligaments, or tendons. It helps assess sports-related injuries, bone fractures not visible on X-rays, arthritis damage, fluid build-up, infections, tumours, and more. For example, MRI can also show bone changes that may predict future cartilage damage and evaluate knee cap (patella) injuries, reduced joint motion, complications from surgical implants, and pain or trauma caused by surgery.
MRI scans are also useful for tracking how cartilage damage changes over time. This can help monitor the progress of knee problems and evaluate the effectiveness of treatment. Your doctor can slow down or even reverse the damage by measuring how much cartilage is affected over time.
An MRI can also guide clinical decisions about needing knee surgery and monitor your recovery after treatment or surgery.
Find an MRI Scan for Knee Cartilage Damage
If you’re worried about knee cartilage damage symptoms, you can book a private MRI scan today. If you’re unsure whether an MRI is suitable for you, one of our expert clinicians is available for a personalised consultation. They can discuss your symptoms and concerns and help you decide what to do next. Remember, with knee cartilage damage, the earlier it can be detected, the better your outcome.
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Kafa, B., et al. (2024). Evaluation of Patella Anatomy for Total Knee Arthroplasty Approaches. https://www.cureus.com/articles/251860-evaluation-of-patella-anatomy-for-total-knee-arthroplasty-approaches#!/
Kato, Y., et al. (2019). A large knee osteochondral lesion treated using a combination of osteochondral autograft transfer and second-generation autologous chondrocyte implantation: A case report. https://www.sciencedirect.com/science/article/pii/S2352320418300555?via%3Dihub
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