The swollen knee (also known as “knee water”) is a common problem caused by the buildup of fluid inside or around the joint. 
Swelling in the knee may occur suddenly or gradually and may restrict the movement of the leg, making walking very irritating.

The stroke in the knee joint develops mainly:

  • After a trauma or a sprain ,
  • Due to arthritis (inflammation of the joint),
  • Sometimes without a precise reason.


Causes of Knee Swelling

The knee has a joint capsule that is like a bag around the entire joint.
The capsule contains synovial fluid that nourishes and lubricates the joint so that it can move smoothly.
The joint capsule acts as a container holding fluid inside the joint.
Knee swelling occurs when excess fluid accumulates inside the capsule.

This can be caused by:

  • bleeding in the joint (hemarthrosis) is usually caused by an injury and swelling in the knee occurs very quickly.
    The swelling can be very intense and can cause stiffness  throughout the leg.
  • An accumulation of synovial fluid (water in the knee): in this case the swelling tends to occur gradually. In some cases the swelling may come and go; in addition, the amount of fluid in the knee is variable. It is usually caused by arthritis  or by arthritis.
  • The swollen knee may be a consequence of surgery , such as replacing the joint with a prosthesis .
    In this case, the swelling disappears several months after the surgery; the painfirst .
    My patients always ask me how long it takes to swell the joint because they are in a hurry to heal.
    I say that healing and swelling are not closely related.
    The patient may return to work as the knee can become swollen painlessly after surgery.


Swelling in the knee suddenly after an injury

Generally a knee that swells suddenly after an injury is caused by a hemarthrosis, meaning the blood collects inside the joint.
In this case, a structure inside the knee is damaged and begins to bleed, increasing pressure on the joint.
The swelling spreads and the knee becomes like a balloon:

  • Red,
  • Warm.

In this case, the joint effusion is seen in the upper, lower and lateral parts of the knee.
The articulation appears:

  • Rigid ,
  • Painfull,
  • Sometimes bruises may be seen .

There are 3 main causes of hemarthrosis:

1) Ligament rupture : a ligament tears completely. This is a common cause and usually involves the anterior cruciate ligament of the knee (ACL).
In case of crusader injury, the knee does not bend more than 90/100 ° and it is impossible to fully extend the lower limb for several weeks.

2) Meniscus injury :  The hematoma occurs if the lesion is in the outer part.

3) Knee fracture : a rupture in one of the bones that form the knee joint. A swollen knee of this type needs urgent medical treatment to avoid complications.

Swollen knee after injury

If the knee swelling develops after a short time of the accident (hours or days), it is most likely due to the increase in synovial fluid in the joint (or synovitis ).
This occurs when something inside the knee is damaged.
The swelling varies from case to case.
If the person puts a hand on both knees, you may feel that the knee is swollen and hot; this is a normal consequence of inflammation.
It is possible to notice a ball in front of the knee after an injury; This is a knee bursitis.

The most common causes of swollen knee are:

1) Meniscus  injury : an injury to the inner part of the joint cartilage of the joint (the inner part of the meniscus  is not vascularized and therefore, when damaged, does not bleed).

2) Knee sprains: it  is the stretching or rupture of ligaments.
The accumulation of fluid in the knee can vary from day to day, usually improving as the patient heals.
It usually takes 6 to 12 weeks for the healing of soft tissue injuries (muscles and joint capsule).
The cartilage lesions may need surgery because there is no blood supply.


Knee gradually swelling without an accident

The possible causes of a knee that gradually swells without a trauma are chronic diseases like:

The swelling may vary depending on the days and activities performed.
Normally, the swelling is not very noticeable.
The arthritis (ie, joint degeneration) is a disease that most often causes a swelling of this type.
Osteoarthritis induces the body to produce extra fluid in the knee.
On days when the leg is overloaded, the knee may ignite producing more fluid to try to protect itself and regenerate itself.

The swelling in the lateral parts can be the consequence of a reduction of the cartilage in these parts of the knee; usually occurs in the initial phase of arthrosis.
The swollen knee on the side is less frequent than on the inner side because this side of the knee is more susceptible to developing arthrosis.
The swelling on the outer side happens especially in the case of valgus knee because there is an overload on the side of the knee.

The tendonitis causes an inflammation of the tendon, especially the quadriceps  in the upper (above the knee cap) and patellar in the lower part, but there is the development of a visible swelling out.

Knee swells quickly without injury

Sometimes the swelling develops rapidly without any trauma.
The most frequent causes of this phenomenon are:

1) Infection:  infections increase the amount of synovial fluid produced. Generally, infections develop after surgery or a deep cut and can reach the joints.
Fighting a joint infection is very difficult and sometimes it is necessary to resort to surgery to solve the problem.

2) Gout :  High levels of uric acid (produced by the digestive process) cause the formation of crystals that are deposited in the joints. The deposit of these crystals causes inflammation in the knee and a slight swelling. The drop is treated with medication and diet adequate. 


Swollen knee on the side

The swelling can occur even outside the joint capsule (extra-articular swelling).
It is usually caused by:

  • An inflammation of one of the bursae of the knee ( bursitis ),
  • trauma to the muscles around the knee (hematoma).

The most common extra-articular swelling can be caused by:

1) Bursitis: bursae are small, fluid-filled pockets located between the bone and soft tissues and serve to reduce friction between structures.
If the friction increases for a certain disease, these pockets may become inflamed.
In this case the swelling does not affect the entire knee, but is located at the level of the bag.
A swelling in the front of the patella can be caused by pre-patellar bursitis (knee of the housewife).
A swelling located at the back of the knee , about the size of an orange, is due to a popliteal bursitis, also called a Baker’s cyst .

2) Hematoma: An abrupt trauma to the soft tissues of the knee can cause bleeding .
Blood that collects around the muscles can accumulate in a hard lump.
If there is only a small bleeding, usually what appears is only a small bruise called a bruise .

Swollen knee after surgery

It is normal for the knee to become swollen after surgery; often the patient also has a fever .
A routine operation such as surgery for broken meniscus (meniscectomy) causes a swelling that lasts for a few weeks.

It is not the case to worry about post-operative swelling; the knee needs a lot of time to deflate.
After an operation to reconstruct the ACL (anterior cruciate ligament), the knee needs at least 4/6 months to dislodge.

One thing that is often observed is that the joint gets thicker after surgery for a fracture;  this is a normal consequence.
This is not a joint stroke because it feels like the knee is hard on the swollen part.



Other causes of knee swelling

Generally the liquid that forms remains inside the knee because the capsule acts as a barrier and prevents spills. However, extra-articular swelling can sometimes occur.

Infections can cause swelling in the knee, in particular:

In this case the doctor prescribes antibiotics to reduce the symptoms.


Rare Causes of Knee Swelling

1) Dislocation of the patella: During flexion-extension, the patella slides in a groove in the front of the knee. An external force can push it to the sides, causing the exit of the anatomical site.
This trauma causes swelling in the knee.

2) Runner Knee: Inflammation of the patellar tendon may cause a slight swelling in the front of the knee.

3) Bone Cancer : There are several types of cancer that can cause a swelling in the knee, also in children.

4) VTE: a deep vein thrombosis is a blood clot that forms in a deep vein, usually in the legs.
Usually these clots are painful and form after prolonged bed rest, surgery or an airplane trip.

5) Hemarthrosis caused by circulation problems: it is a sudden bleeding that occurs in the joint in people who:

  • They have blood clotting problems,
  • They are taking blood thinning medicines such as Coumadin.


Swollen knees during pregnancy

Often during pregnancy happen swollen knee problems, especially from the second trimester.
This phenomenon occurs because the child increases in weight and causes an increase in the pressure of the uterus against the inferior vena cava (a large vein that carries blood from the legs to the heart).
This can lead to  fluid retention  at knee level, but can also affect:

  • The hands,
  • The feet.

To reduce swelling in the legs it is necessary to avoid standing for too long, trying to rest as much as possible while keeping your legs elevated.
Staying too long standing increases pressure on the vena cava, decreasing the quality of the blood circulation.

The heat tends to increase the swelling of the legs, while the cold gauze can decrease the swelling in the knees.

One needs to be very careful with swollen legs during pregnancy because they can be a sign of a more serious condition known as preeclampsia .
Consult your doctor to rule out a more serious illness if swelling:

  • Do not go through the home,
  • Involve different parts of the body.

It is necessary to inform the doctor if the swollen knee occurs with:


Swollen knees in children

Often children have swollen knees due to a fall or injury, but sometimes the swelling may be associated with other causes.
The swollen knee due to a sprain is less evident compared to adults.

The Lyme disease can cause inflammation  and persistent swelling in the joints.
Lyme disease is most widespread in the northeastern United States; therefore, especially in the areas with greater risk it is important to rule out this disease.

Children may have fluid in the knee due to:

  • An infection,
  • Juvenile rheumatoid arthritis .

The arthritis Septic is a painful infection accompanied by heat and swelling. The bacteria that causes the infection usually affects the knees, but can also occur in other joints.


Treatment for swollen knee

The methods for knee swelling are many and many times the therapeutic choice depends on what caused the swelling:

1) Ice: can be used to decrease blood flow and therefore reduce swelling and pain . It is important to use the ice correctly at 10-minute intervals.

2) Compression: To reduce swelling, use elastic bandages (such as kinesio taping ) or knee pads to create the right knee compression.

3) Medicines drugs nonsteroidal anti-inflammatory drug (NSAID) such as Voltaren Advil or may be prescribed to reduce swelling of the knee.

4) Aspiration: The fluid inside the knee can be drained with a needle by the doctor. Sometimes the liquid can come back.

5) Infiltration of cortisone : a cortisone is a steroid hormone, to suppress the immune system, reduces:

  • The inflammation,
  • I adore.



Natural Remedies for a Swollen Knee

If the swelling and pain last more than 48 hours or are accompanied by fever and severe pain, it is necessary to undergo medical examinations to arrive at a correct diagnosis.
Avoid exerting weight on the sore knee until it is dislodged.
An elastic band does not help to dislodge the knee; it is best to make a green clay compress to use throughout the night.

Ice. Wrap some crushed ice in a cloth and place on the knee for 20 minutes. Ice improves a swollen, sore knee.
Repeat the treatment every 2-4 hours, keeping the leg elevated.
Ice is useful only:

  • In the first 24 hours after an injury,
  • After the onset / worsening of pain.

Elevation. You can put your foot on some pillows.
One trick to keeping your leg higher during the night is to place something under the foot of the bed, so the body gets the ankles higher than the heart at night.

Rehabilitation exercises.  For those suffering from knee arthrosis it is important to perform exercises of:

  • Stretching,
  • Muscle toning.

These exercises help to warm up and stretch the muscles and are very useful after long periods of rest.
Regular exercise is very useful for improving:

  • To physical form,
  • Muscle tone.

Do not overdo the exercises if you are inexperienced.
Choose a gym that does not cause pain, such as:

  • Swimming,
  • Yoga.

Obesity. In case of being overweight , it is necessary to regulate the diet to lose the excess pounds. To do this always rely on experienced and qualified professionals.
Being overweight creates more pressure on joints and muscles, especially at the knees and ankles.
Excessive pressure favors inflammation of the joints and thus is a risk factor for developing swollen knee.

Massage therapy
The massage therapy is a useful treatment and may be associated with other described to remove the knee swelling.
Manual therapy promotes:

  • The release of endorphins and other chemicals,
  • An efficient circulation.

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