Fluid in the knee is a physical complaint shared by many people. At a higher stage, it can lead to a significant limitation in the ability to walk and stand.
What is fluid in the knee?
In medical terminology, the term knee joint effusion is predominantly used. In knee joint effusion, externally visible changes may be noticed in the affected knee joint. Colloquially, the expression “fluid in the knee” is widely used. This refers to a number of conditions that contribute to fluid accumulation within the knee area. In medical terminology, the term knee joint effusion is predominantly used. In the case of a knee joint effusion, externally visible changes can be noticed in the affected knee joint. This is accompanied by internal deformities. The fluid consists of a pus-like consistency (pyarthros), the body’s own joint fluid (synovial fluid) or blood (hemarthros). It should be noted that fluid accumulation is not a disease, but a symptom. In general, a distinction can be made between an acute and a chronic complaint. The former occurs in all age groups, whereas a chronic course develops predominantly in people of advanced age. Individual forms of fluid accumulation are also diagnosed among professional athletes. Knee joint effusion can be attributed to excessive stress and associated knee injuries.
Causes
Fluid in the knee always occurs as an associated condition. The cause of acute knee joint effusions is trauma secondary to injury. Examples include cruciate ligament rupture, patellar luxation, osteochondral fracture, or fracture of the tibial plateau. In rare cases, a peripheral meniscal lesion may be implicated as a cause of transient fluid accumulation. A common trigger of a chronic course is excessive irritation of the synovial membrane. It leads to increased production of joint fluid (synovial fluid). In medicine, other known causes are meniscal lesion, patellar tendonitis and plica syndrome. In these cases, an imbalance is found between production and reabsorption. The result is an accumulation of fluid in the knee joint capsule. In rare cases, fluid in the knee is brought on by infection. With an inflammatory response, fluid reabsorption is impeded, resulting in a steady accumulation of fluid. Finally, rheumatic diseases and osteoarthritis may be implicated as possible causes.
Diseases with this symptom
- Osteoarthritis
- Cruciate ligament rupture
- Patellar luxation
- Meniscus injuries
- Knee joint osteoarthritis
- Patella fracture
Diagnosis and course
Knee swelling is the first sign that fluid has accumulated in the knee. The knee assumes an atypical shape, which is accompanied by a continuous increase in size. This is accompanied by a limitation of movement and partial stiffness. Pain is felt under high pressure, which worsens as the condition progresses. If fluid is suspected to have accumulated in the knee, a general practitioner or orthopedist should be consulted. The physician begins with a medical history that focuses on the physical condition. A physical examination plays an important role. During this examination, the “dancing patella” (kneecap) is checked for functionality. At the same time, the knee is analyzed by ultrasound, X-ray and computer tomography. If an infection is suspected, a microbiological examination can be performed. Fluid is collected with a puncture and checked for a possible pathogen.
Complications
If a fluid-filled protrusion is present in the back of the knee, it is a Baker’s cyst, which leads to complications if it presses on nerves and vessels. Knee swelling is present as a complication in most cases. In addition, the Baker’s cyst can rupture, or tear, due to excessive growth and pressure during knee flexion. Because the synovium then leaks into the surrounding tissue, inflammation and even more severe pain are not uncommon.Due to gravity, synovial fluid flows into the muscles of the lower leg and sometimes even into the ankle area, where pressure builds up that cannot escape. This results in compartment syndrome. This exerts pressure on the nerves and blood vessels and, if not treated surgically in time, may lead to lower leg amputation. If the knee joint is punctured to remove the fluid, the knee joint may refill with synovium and swell after a temporary improvement. If necessary surgical treatment, minimally invasive, by arthroscopy or open, is delayed too long, cartilage damage or damage to the menisci cannot be ruled out. This risk is increased if the cause is rheumatoid arthritis. If inflammation (arthritis) develops in the knee joint due to microorganisms (viruses or bacteria), cell and tissue damage can occur, as well as the death of the joint elements. This condition, which also involves a reduction in general condition, can occur preoperatively but also postoperatively.
When should you go to the doctor?
Fluid in the knee, or more casually, “water in the knee,” is always a reason to see a doctor. Also known as knee joint effusion, it is a symptom of several conditions. The fluid in the knee is either joint fluid, a purulent secretion or blood. Fluid in the knee comes in acute and chronic varieties. While acute knee joint effusion occurs in all age groups, chronic joint effusion mainly affects older individuals. Fluid in the knee also occasionally occurs in professional athletes. Anyone who notices swelling in one knee or both knees should seek medical attention immediately. Swelling in knees indicates fluid accumulation. There are several possible causes for fluid in the knee. The sooner medical treatment begins, the better. Doctors have numerous diagnostic methods at their disposal. X-rays, ultrasound and computer tomography are common examination methods for fluid in the knee. If the examination results indicate an infection, this is followed by a knee puncture, in which the physician removes some of the fluid in the knee for microbiological examination. If there is fluid in the knee, time is of the essence. Seeing a doctor and starting treatment early can help prevent a lengthy and painful course of treatment. At the end of treatment, the physician may prescribe physical therapy for his patient to regenerate the traumatized knee joint.
Treatment and therapy
After a diagnosis, the physician decides what therapy to initiate. As a rule, treatment is causal. Accordingly, the cause is treated so that the fluid in the knee can decrease in the long term. If a knee joint effusion is the result of trauma, immobilization of the knee is sought. First and foremost, it is important to treat the injury. On the other hand, chronic courses are accompanied by medication, while an infection is treated with antibiotics. In severe cases, it is necessary to operate on the knee. Meanwhile, it is no longer necessary to open the entire knee. Instead, small areas are punctured, after which the fluid is drained. The surgical procedure aims to reduce the accumulated fluid in the knee to relieve pressure. However, it is often possible to eliminate the swelling by immobilizing the knee joint. Elevation of the corresponding extremity also provides relief. If necessary, this can be accompanied by a therapeutic intervention in the form of a joint puncture. Herbal and homeopathic remedies finally round off a treatment. In retrospect, physiotherapy is recommended to regenerate the knee joint after most of the fluid in the knee has receded.
Outlook and prognosis
Fluid in the knee does not have to cause particular discomfort or complications in every case. However, the causes and symptoms are relatively different. In most cases, fluid in the knee occurs because of inflammation, such as when a cruciate ligament tear has occurred. If this injury is not able to heal properly, the fluid can accumulate. This is especially the case if the leg continues to be heavily loaded. There may be severe pain and restriction of movement due to the fluid accumulation. Furthermore, osteoarthritis, can be responsible for the fluid in the knee.This also results in pain and restrictions on movement. The quality of life decreases in most cases. Treatment is primarily causal and aims above all to cure the underlying disease. If this is cured, the fluid in the knee usually also disappears by itself and no further complaints occur. It is not uncommon for medications to be used to prevent or treat inflammation. In severe cases, the fluid can also be removed directly by the doctor. Furthermore, there are no restrictions or discomfort for the patient.
Prevention
With preventive measures, it is possible to reduce the risk of knee joint effusion at any age. In particular, it is important to avoid excessive stress on the knee through sports activities. The best-known high-risk sports include squash and skiing. These sports should be pursued only in moderation. At the same time, it is recommended to strengthen muscles, tendons and ligaments. Jogging, swimming and stretching can help in this regard. If a knee injury has already been sustained, therapeutic measures can be taken for regeneration and stabilization. In this way, the risk of a relapse is reduced. It may even be advisable to start physiotherapy.
