Why Is my Knee swollen-what does this mean?

What is swelling? What does it mean and what should be done in response to it? There are different causes of swelling and to understand how to respond to swelling it is really important to try and distinguish between the different causes. Trauma. This can be a sporting injury, direct blow or fall, but there is a very obvious moment of injury. Speed of swelling of the knee is really important in this instance. If the area swells within an hour it is suggestive of blood, (a haemarthrosis), which flags up the possibility of more serious injury such as a fracture or ligament injury. In the knee we would often consider fracture to the tibial plateau, or ACL rupture, depending on the nature of the injury. In these situations rapid action must be taken so that the injured person sees a clinician immediately. Direct blows to the knee area can also result in a bleed within the soft tissues, not the joint. Although these can often be managed with physiotherapy again it is important to ensure that a more serious injury such as quadriceps rupture is not overlooked. Swelling in a crescent shape below the kneecap. This is normally fluid in the fat pad that sits as a ‘u’ shape under and around the bottom half of the patella, (knee cap). This is very common in all age groups and can be suggestive of the kneecap knocking into the fat pad and disturbing it. For more on this read my blog on fat pads:

The infrapatellar (Hoffa’s) fat pad explained

Fat pad swelling can occur alongside osteoarthritis of the knee, and recent literature suggests it may be part of the inflammatory cycle. When I see a large swollen fat pad I am always keen to see that come down in size. Ice massage to oiled skin can be very effective, (the  ice-it-away is brilliant for this) as can taping techniques to off load the fat pad or stabilize the patella. A physiotherapist should be able to help with this. Swelling over the front of the patella. This can be pre-patellar bursitis, an inflamed bursa, (a pouch of fluid). It is often seen in people after a direct blow to the front of the knee or after a lot of kneeling. Treatment is to avoid direct pressure, ice, elevate, and discuss the use of anti-inflammatory medications from a prescribing clinician. Non-traumatic knee joint swelling. If the knee joint is swollen without trauma the most common cause will be osteoarthritis, the wear and tear arthritis. Swelling can make the joint feel stiff when in one position for too long, and can make the communications between the knee and brain sluggish which in turn can inhibit the quadriceps muscles on the front of the thigh. This can lead to a feeling of lack of confidence in the knee and the sense that it might ‘give way’. For these reasons it is important to try and get this swelling down. First line attempts can be elevation and ice, but anti-inflammatory medications can also be used. A prescribing clinician should be consulted regarding this. Finally there are more unusual causes of knee swelling that are more systemic in nature. In other words the body’s immune system has got in a muddle and sets off an inflammatory response inappropriately. Clues to this can be multiple joints swelling, joints feeling stiff on waking, and often an accompanying sense of feeling unwell or fatigued. A GP or rheumatologist is the best person in this circumstance. Ultimately swelling is unhelpful. It restricts movement, makes the joint feel stiff, and can interfere with muscular firing patterns. However, as this blog has hopefully explained, there are many different potential causes and the best starting point is to ask, ‘why is this swelling present?’

Insight Institute of Neurosurgery & Neuroscience (IINN) 09-11-2023

I found your blog post on why a knee is swollen informative and helpful in understanding the possible causes and implications. Thank you for sharing.

Claire 09-01-2024

Absolute pleaseure and glad it helped.

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