A knee effusion is a term used to describe an excess collection of fluid in your knee joint.
An effusion can be caused by many things including
- knee fracture
- osteoarthritis
- infection
- gout
Alternate names
- water on the knee
Symptoms
The symptoms depend on the cause. These can include:
- Pain
- Stiffness
- Swelling
- Bruising
Causes
Fluid buildup from trauma
Some injuries that can cause fluid buildup in and around the knee joint are:
- Broken bones (fractures)
- Meniscus tear
- Ligament tear
- Overuse injuries
- Operation on the knee including knee arthroscopy
Fluid buildup from underlying conditions
Osteoarthritis is the most common cause of knee issues.
Other diseases and conditions which can result in a buildup of fluid in and around the knee joint include:
- Infection
- Rheumatoid arthritis
- Gout
- Pseudogout
- Cysts
- Kneecap (prepatellar) bursitis
- Tumors
Risk Factors
Many sports can pre-dispose to knee effusion. Sports like football, soccer or tennis, are especially risky as they involve ‘cut and run’ manoeuvres.
Also osteoarthritis is a risk factor.
Being overweight results in more pressure being placed on the knees. The increased wear and tear on your knee joint can result in an overproduction of joint fluid.
Investigations
Some tests which may be ordered for you include xrays, MRIs, joint aspirations and blood tests. These can help differentiate what the cause may be.
Complications
If your effusion isn’t treated it can result in severely limited movement of your knee. Depending on the cause of your knee effusion a whole host of complications could potentially arise.
Treatment
Treatment for Knee Effusion focuses on treating the underlying disease or injury.
- Osteoarthritis: Aspirating the built-up fluid from your knee joint can alleviate the pressure . Also a corticosteroid injection may be chosen to treat the inflammation.
- Gout or pseudogout: Both of these cause crystals to deposit in joints and may cause inflammation in the joint and surrounding soft tissues. Your doctor may start you on medications to control these conditions.
- Infection: Antibiotics may be used to treat underlying infection. You may need repeated aspiration of the infected joint or surgery.
- Arthroscopic knee surgery: Using camera on a flexible stick, an orthopaedic surgeon can look at the inside of your knee for signs of damage. The surgeon can then also repair damage inside your knee.
- Joint replacement: Most people with osteoarthritis of the knee don’t require surgery. But if bearing weight on your knee joint becomes near impossible surgery may be recommended.
Looking After Yourself
Taking care of yourself when you have water on the knee includes:
- Rest: Avoid weight-bearing activities as much as possible when your knee is painful and swollen.
- Ice and elevation: Cold therapy can help control pain and swelling. Apply ice to your knee for 15 to 20 minutes every two to four hours. You may use a bag of ice, frozen vegetables or an iced towel cooled down in your freezer.
- Pain medication: paracetamol is often effective at relieving pain. NSAIDs are effective for relieving pain and inflammation. If these don’t relieve the pain, ask your doctor about prescription medications.
- Muscle-toning exercises: If your thigh (quadriceps) muscle or hamstring muscles are weak, your doctor may refer you to a physiotherapist to learn how to strengthen these muscles to better support your knee.
- Managing your weight: Losing weight will minimize the amount of weight your knees have to support when you engage in weight-bearing activities.
Seeking Advice
Your Family Doctor (GP)
Your Family Doctor will be able to diagnose and help treat your problem. He or she will be able to
- tell you about your problem
- advise you of the best treatment methods
- prescribe you medications
- and if necessary, refer you to Specialists (Consultants) for further treatment
Having water on the knee because of an underlying condition doesn’t necessarily limit your mobility or decrease your quality of life. See your doctor promptly if:
- You injure your knee
- Self-care measures or prescribed medications don’t relieve the pain and swelling
- One knee becomes red and feels warm to the touch as compared to your other knee
Prevention
This condition is usually due to a chronic health condition or traumatic injury. Sometimes you can’t avoid knee trauma but you can take safety measures such as wearing a knee brace to protect your knee joint during physical activity.
To avoid this condition:
- Regular visits to your doctor: If you have a chronic health condition, such as osteoarthritis, rheumatoid arthritis or gout you should visit your doctor regularly to make sure you have it adequately managed.
- Look after your knees: If you’re overweight and want to lose weight, make sure you ease into it. Avoid excessive wear and tear on your knees by choosing an aerobic activity that doesn’t place continuous weight-bearing stress on your knee joints (eg running). Some good choices include water aerobics and swimming.
F.A.Q. | Frequently Asked Questions
I have a small effusion, should i expect to have surgery?
Usually surgery isn’t required unless the tests show you have a ligament or cartilage injury.
What’s a knee effusion with a Baker’s cyst?
The excess fluid in the knee is called an effusion and a bakers cyst is formed when this fluid extends into the calf. This can rupture and mimic symptoms of a deep vein thrombosis (DVT).