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Knee inflammation is a common reason people experience swelling, stiffness, or aching around the knee. It may develop after increased physical activity, prolonged standing, or a minor injury, but it can also come on gradually without an obvious trigger. For some people, symptoms settle with rest and simple care. For others, knee discomfort keeps returning or begins to interfere with walking, work, or sleep.
Inflammation in the knee is not a condition on its own. It is the body’s response to irritation or stress affecting the knee joint or the surrounding tissues. Understanding what is driving that inflammation is often the key to managing symptoms effectively and preventing it from becoming a recurring problem.
This article explains what knee inflammation means, the symptoms to look out for, the common causes and conditions linked to it, and the treatment options that may help. It also outlines when it is sensible to seek medical advice.
What is knee inflammation?
Knee inflammation occurs when tissues within or around the knee joint become irritated, leading to swelling, stiffness, warmth, and pain. It is a protective response by the body, designed to support healing. However, when inflammation persists or keeps returning, it can limit movement and affect daily activities.
Inflammation develops when blood flow to the knee increases and chemical signals are released as part of the healing process. In the knee, this may involve the joint lining, cartilage, ligaments, tendons, or small fluid-filled sacs that reduce friction during movement. In some cases, inflammation develops slowly over time due to repeated strain. In others, it may appear suddenly after an injury or flare up of an underlying joint condition.
Common symptoms of knee inflammation
The symptoms of knee inflammation can vary, but several patterns are commonly seen. Swelling is often the most noticeable feature and may cause the knee to feel tight or puffy, particularly by the end of the day. Some people experience stiffness after resting or when they first wake up, which eases slightly once they start moving.
Pain may feel dull and aching or sharper with certain movements, such as climbing stairs, squatting, or standing up from a chair. The knee may feel warm to the touch, and bending or straightening it fully can become uncomfortable. In more persistent cases, the knee may feel weak, unstable, or easily fatigued during routine activities.
What causes knee inflammation?
Knee inflammation can arise from several factors, and more than one may be present at the same time. Doctors usually consider how mechanical stress, injury, and joint health interact, rather than assuming there is a single cause.
Repeated strain is a common trigger. Sudden increases in exercise, frequent kneeling or squatting, prolonged standing, and sports involving running or twisting can all overload the knee. Even minor strains to ligaments or tendons may lead to inflammation if the knee does not have enough time to recover.
Inflammation may also result from changes within the knee joint itself. Cartilage wear, irritation of the joint lining, or increased joint fluid can all contribute to swelling, stiffness, and pain. In some people, inflammation is linked to medical conditions that affect the immune system or how the body processes certain substances.
Common conditions associated with knee inflammation
Knee inflammation is often related to an underlying condition affecting the joint or surrounding tissues. Identifying the cause helps guide treatment and reduces the likelihood of symptoms returning.
Osteoarthritis of the knee
Osteoarthritis is one of the most common causes of knee inflammation. As cartilage gradually thins, the knee becomes less effective at absorbing load. This can irritate the joint lining, leading to swelling, stiffness, and aching that often worsens after activity or later in the day.
Meniscus tears
The meniscus is a cartilage structure that cushions and stabilises the knee. Tears may occur suddenly with twisting movements or develop gradually over time. Meniscus tears can cause swelling, pain with bending or squatting, and sometimes a catching or locking sensation.
Ligament injuries
Injuries to ligaments, such as the anterior cruciate ligament or collateral ligaments, can trigger significant inflammation. Swelling may appear soon after injury and may be accompanied by pain, instability, or difficulty bearing weight.
Knee bursitis
Bursitis occurs when small fluid-filled sacs around the knee become irritated, often due to prolonged kneeling, repetitive movements, or pressure on the knee. Swelling is usually localised and may be tender, sometimes without deep joint pain.
Inflammatory arthritis
Conditions such as rheumatoid arthritis cause inflammation driven by immune system activity rather than mechanical strain alone. Knee inflammation in these cases may be persistent, affect both knees, or be associated with prolonged morning stiffness and other joint symptoms.
Gout and crystal-related arthritis
Gout occurs when uric acid crystals build up within a joint, leading to sudden and intense inflammation. While the big toe is commonly affected, the knee is also a frequent site. Swelling may develop rapidly and can be accompanied by warmth and significant discomfort.
Baker’s cyst
A Baker’s cyst is a collection of joint fluid behind the knee that often develops in response to ongoing inflammation within the joint. It may cause a feeling of tightness or fullness at the back of the knee, especially when bending or straightening the leg.
Why knee inflammation sometimes keeps coming back
Knee inflammation may improve initially but return if the underlying cause is not fully addressed. Continuing activities that overload the knee, returning to exercise too quickly after injury, or having weak or imbalanced muscles around the joint can all contribute to recurrence.
In some cases, pain settles but subtle changes in movement develop as the body tries to protect the knee. Over time, these altered movement patterns can place extra strain on certain structures and trigger repeated inflammation.
How knee inflammation is assessed
Assessment begins with understanding your symptoms. Our doctors will usually ask when the swelling or pain started, what makes it better or worse, and how it affects daily activities. A physical examination helps identify areas of tenderness, swelling, reduced movement, or instability.
Imaging such as X-rays or scans may be useful in certain situations, but they are not always required. Scan findings do not always match symptom severity, and knee inflammation is often best understood by combining clinical assessment with imaging rather than relying on scans alone.
Treatment options for knee inflammation
Treatment depends on what is causing the inflammation, how severe it is, and how long it has been present. The goal is to reduce pain and swelling while addressing contributing factors to prevent symptoms from returning.
Activity modification and symptom control
In the early stages, reducing activities that irritate the knee can help inflammation settle. This does not usually mean complete rest. Gentle movement is often encouraged to prevent stiffness and muscle weakness, while avoiding positions or activities that repeatedly strain the joint. Short-term measures to relieve discomfort may support recovery when used appropriately.
Physiotherapy and rehabilitation
As inflammation improves, rehabilitation becomes important. Physiotherapy focuses on strengthening the muscles that support the knee, improving flexibility, and correcting movement patterns that overload the joint. This is particularly helpful for people who are physically active, have physically demanding jobs, or have had previous knee injuries.
Minimally invasive treatments for persistent knee inflammation
When knee inflammation does not improve with activity modification and physiotherapy, minimally invasive injection-based treatments may be considered. These treatments are non-surgical and are aimed at reducing inflammation directly within the knee joint or surrounding tissues, allowing pain to settle and movement to improve so rehabilitation can continue.
The type of injection used depends on what is driving the inflammation and the condition of the knee joint.
Coreflex injections
Coreflex injections are used to address knee inflammation by targeting irritated tissues in or around the knee joint. They combine anti-inflammatory medication with local anaesthetic to help calm inflammation from the affected area.
By reducing local inflammation and discomfort, Coreflex injections may help improve knee mobility and function, particularly in people whose pain is limiting movement or rehabilitation progress.
Platelet-rich plasma (PRP) injections
Platelet-rich plasma (PRP) injections for knee inflammation involve injecting a patient’s own concentrated platelets into the knee joint to help reduce pain and support tissue repair, particularly in conditions such as arthritis or tendon-related injuries.
Intra-articular knee injections
Intra-articular injections involve injecting a gel-like substance directly into the knee joint. This gel is designed to improve the quality of joint fluid, which can become less effective when the knee is inflamed or worn.
By improving lubrication and cushioning inside the joint, these injections may help reduce stiffness, ease inflammation-related discomfort, and improve knee movement during daily activities such as walking or standing.
When surgery may be considered
Surgery is not the first-line treatment for most cases of knee inflammation. It is usually considered only when there is clear structural damage, mechanical symptoms such as locking, or failure of non-surgical and minimally invasive treatments.
What to avoid when you have knee inflammation
Certain habits can slow recovery. Persisting with activities that worsen swelling, frequent kneeling or deep squatting, or following unsupervised exercise routines that increase pain may all prolong inflammation. Ignoring early symptoms and delaying assessment can also make treatment more difficult.
When should you see a doctor for knee inflammation?
Medical advice is recommended if knee swelling or pain does not improve with rest, if the knee feels unstable or locks, or if inflammation keeps returning. Sudden severe swelling, redness, increasing pain, or difficulty bearing weight should also be assessed promptly.
Frequently asked questions about knee inflammation
Is knee inflammation the same as arthritis?
Not always. Arthritis is one possible cause, but inflammation can also result from overuse, injury, or irritation of soft tissues around the knee.
Can knee inflammation go away on its own?
Mild inflammation may settle with rest and activity adjustment. Persistent or recurring symptoms often need further assessment to address the underlying cause.
Should I exercise or rest when my knee is inflamed?
Complete rest is rarely helpful long term. Gentle, appropriate movement is usually encouraged while avoiding activities that worsen pain or swelling.
Why is my knee swollen but not very painful?
Inflammation can increase fluid within the joint without causing severe pain initially. Swelling alone still indicates stress within the knee.
How long does knee inflammation usually last?
This varies. Some cases improve within days to weeks, while others persist if contributing factors are not addressed.
Key takeaways and next steps
Knee inflammation is common and often manageable, especially when addressed early. Understanding what is driving the inflammation helps guide treatment and reduce the risk of recurrence. If knee symptoms are affecting daily activities or not improving as expected, a pain assessment can help clarify the cause and discuss appropriate treatment options, including minimally invasive approaches where appropriate.
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