Knee swelling causes ?
A swollen knee is a common problem. Many people call this “water on the knee.” However, determining the cause of knee swelling can be a challenge. Swelling may be acute or chronic. It may be associated with a recent injury or may have a gradual onset. The swelling can be within the knee or around the knee. Determining the treatment of the swollen knee depends on what caused the problem. Here you will learn how to determine the cause of knee swelling.
Fluid Inside The Knee Joint
If it is determined that fluid is inside the knee joint, the next step is to determine if there was an associated injury.
- Acute Injuries
An acute injury is a traumatic event that has occurred recently (within the past 24-48 hours). Acute injuries are distinct from chronic conditions because the knee swelling developed suddenly, as a result of the injury.If the injury is acute, the next step is to determine the type of fluid within the knee. There are specific injuries that can cause bleeding in the knee, and others that may cause a sudden increase in the production of joint fluid.
- Blood in the Knee
Two conditions commonly cause the accumulation of blood within the knee; these are anACL tear and a fracture of the bone and cartilage of the knee. These injuries allow blood to enter the joint and will create a large, swollen knee. When bleeding is the cause of knee swelling, the onset is rapid, and the swelling can be intense. Fluid usually accumulates within minutes of the injury.
- Non-Bloody Fluid in the Knee
Acute injuries that cause the accumulation of non-bloody fluid within the knee include meniscus tearsand ligament sprains. The knee swelling seen with these injuries is acute in onset, but less rapid than blood accumulation. Typically patients with these injuries will notice fluid accumulation hours to days after the injury (rather than within minutes as seen with bleeding into the knee). The amount of fluid can be significant, but it is not typically tense as seen with blood accumulation.
- Blood in the Knee
- Chronic Conditions
Chronic injuries cause a gradual onset of knee swelling. This fluid may fluctuate in amount and the symptoms may come and go. This is the most common type of swelling and often seen as a result of knee arthritis or wear-and-tear.
- Knee Arthritis
Knee arthritis causes the body to produce extra fluid in the knee joint. The amount of fluid tends to fluctuate over time. Patients with knee arthritis often notice the affected knee is larger than the other. The amount of fluid often corresponds with the amount of activity the patient has been doing–more significant activities cause more swelling.
- Knee Arthritis
- Rapid Onset of Swelling, No Injury
The last broad category of swelling is the rapid onset of fluid within the joint, but no recent injury to the knee. The most common causes of this type of fluid accumulation are due to infection or gout.
Infections can cause fluid to accumulate within the knee joint. Infections can be caused by contamination in the knee, such as from surgery or a wound to the knee, or a systemic infection that spreads to the joint. Infections inside a joint are problematic because your body has a hard time fighting infections within this space. Surgery may be needed to clean out the infection.
- Gout and Pseudogout
Gout is due to the accumulation of uric acid crystals within the fluid of your knee. Uric acid is a substance produced as part of digestion. In order to properly digest food, and rid our body of waste, our bodies produce substances such as uric acid to transport waste material. People with gout accumulate uric acid crystals within joints, leading to inflammation and swelling.Pseudogout is a similar problem, only a different type of crystals accumulates within the joint. In patients with pseudogout, calcium crystals simulate an inflammatory reaction within the joint, leading to a swollen knee.