Knee bursitis: causes, symptoms, home remedies
What is knee bursitis?
Have you ever had a moment where you hit your knee so hard you thought it was fractured? That is what knee bursitis can feel like. It can seem rather alarming as the knee will swell like nothing else!
Knee bursitis or prepatellar bursitis is a condition characterised by marked swelling in the bursae of the knee. Other layman terms given to this condition are: housemaid’s knee, coal miner’s knee and carpet layer’s knee.
Most of you won’t realise that we have bursae across our entire body. There are more than 140 bursae across our body! They develop after birth as our bodies way of dealing with friction between two surfaces.
Bursae are basically sacks filled with fluid. Think of a plastic bag filled with water and you will be close to what they look like.
As mentioned previously, the job of the bursae is to prevent friction. So, you will find them in areas of high friction like in the knee, the elbow, the hip and lots of other places.
Some statistics about knee bursitis:
Bursitis is much more common in Males than females. In fact, more than 80% of all bursitis patients are male
You can have bursitis at any age, but they are more common in adults between the age of 40-60.
Where are these bursae in the knee?
There are many different bursae across our knee, but the one usually responsible for knee bursitis lies between our kneecap and skin. It’s called the prepatellar bursae and can be easily irritated because its compressed and sheared when we kneel.
Causes of prepatellar bursitis
We can split the causes of knee bursitis into two main categories:
- Traumatic, acute onset
Bursitis can occur where there is a direct blow to the area which causes bleeding into the bursae. This will occur quickly, usually immediately at the time of the incident.
Examples of such trauma might be tripping and falling directly onto the knee.
Remember that with any traumatic onset it is very important to get imaging. This is so that we can rule out more serious diagnoses like fractures around the knee. Fractures will also cause the knee to swell up and become very painful and they could mimic knee bursitis.
- Micro-trauma, chronic onset.
Repeated stress on any structure in the body will eventually cause injury. The shearing and compressive forces of skin and bone against the bursae eventually cause it to become irritated.
The biggest cause of irritation to the pre-patellar bursae is repetitive kneeling.
Another cause, not previously mentioned is due to infection. This will be described in more detail as we talk about the different types of knee bursitis.
Types of knee bursitis.
Prepatellar bursitis looks the same, but there are two very different causes for this diagnosis. You can have an infective bursitis (medical professionals will refer to this as a septic bursitis), or a non-septic bursitis resulting from inflammation.
It is very important to differentiate between these two types as the septic bursitis can be very dangerous and treatment for this is very different.
Both septic and non-septic bursitis will present with:
- Warmth (this is more associated with a septic joint so something to keep an eye on)
- Tenderness (may or may not be present – see symptoms and diagnosis)
Things to look out for with septic bursitis:
Although most clinical symptoms are very similar, an associated fever is highly correlated with septic bursitis. If you have a fever greater than 37.7 0C and a swollen and red joint, then assume you have a septic bursitis.
Another clue to look out for is any cuts or scratches around the site of the swollen knee. The prepatellar bursae is so close to the skin, meaning bacteria can enter the bursae through a cut or scratch.
One last factor would be if you have any immunosuppressing conditions such as rheumatoid arthritis or diabetes. These conditions may inhibit your body’s ability to fight bacteria and predispose it to infection.
Septic bursitis can be very dangerous and needs to be treated promptly to avoid complications. We will talk about this a little later in this article.
Symptoms of knee bursitis?
Knee bursitis can look very concerning as the knee swells like a balloon. And it can happen very quickly in the acute setting. It could also occur overtime if the knee is subject to repeated loads.
You may encounter symptoms including: redness, swelling, warmth and tenderness over the knee.
Keep in mind, if your knee bursitis is a result of micro-trauma like repeated kneeling, there may be no pain or tenderness associated. You may just experience marked swelling and redness. It’s still normal to have swelling with no pain and this isn’t a reason to be concerned.
Knee bursitis – diagnosis and imaging
In formulating a diagnosis of prepatellar bursitis, most of the work is in the history of injury.
Chronic knee bursitis is reasonably easy to diagnose. You would present with marked swelling due to a repetitive activity which stresses the knee, plus or minus pain.
The acute bursitis is a little harder to diagnose, as there are several other conditions which could mimic this one.
If the condition was from a fall onto the knee, then a fracture needs to be ruled out.
If the condition came on without any blunt force, then we need to rule out conditions such as:
- Inflammatory arthritis
- Joint effusions resulting from meniscal or ligamentous injury
If the injury was a result of blunt force, then an X-ray is needed to rule out any fractures.
The Ottawa knee rule is a great place to start with any knee injury, to see if an X-ray is needed.
If you are still unable to weight bear and there is nothing seen on X-ray, then a CT will be warranted to rule out any small fractures that may have been missed with plain X-ray imaging.
In the event of an acute swollen knee without any real cause, there is reason to suspect septic bursitis. In this event a blood test can be helpful to see if there are any markers that would indicate inflammation.
If there is still uncertainty after imaging and blood tests your doctor can aspirate the joint to send the fluid for further investigation.
On top of helping with a diagnosis, joint aspiration has the added benefit of relieving pressure in the bursae. This can help with pain.
Is there an expected recovery time for knee bursitis?
Studies show recovery time for prepatellar bursitis will vary widely. In my experience there is no magic ball telling us exactly when you will recover, but I can give you a guide.
For all most types of knee bursitis the normal recovery time will be between 1-6 weeks. This may vary for the chronic micro-trauma knee bursitis. For the micro-trauma bursitis, the bursae will still be irritated until management strategies are put into place.
Best treatment for knee bursitis, including home remedies and exercise
Treatment for a septic knee bursitis and a regular prepatellar bursitis will vary. If there is suspicion that your bursitis is septic (infected), then it is recommended that you consult a medical professional to perform the required investigations.
Also, if you have had trauma to the knee, resulting in major swelling, you will still need to see a medical professional to ensure you don’t have any other conditions like a fracture.
If you have normal bursitis, either from overuse or an acute incident, then it’s recommended that you trial conservative therapy first.
Conservative therapy for bursitis:
The initial treatment of knee bursitis will involve the PRICE scheme. This means:
- Protect injury
For knee bursitis this may mean to stop or modify the activity that is causing pain and discomfort.
- Rest injury:
Rest doesn’t mean lying in bed all day. It may be as simple as modifying what you are doing to avoid things like stairs and squatting.
Icing can be done using a frozen bag of peas wrapped in a damp tea towel. Standard icing regimes include 15-20 minutes of icing and then a 45 minute break.
Compressing the knee can help to alleviate the build-up of fluid by helping to pump the fluid out of the bursae. You can buy regular Tubigrip online, or from the chemist to help and wear it throughout the day.
Elevation also helps to flush the fluid from the knee by using gravity to help push the fluid out of the affected bursae.
In my experience, there are minimal exercises that will be beneficial in the treatment of prepatellar bursitis. General walking will help to keep some of the fluid at bay, however this won’t fix the condition.
Sometimes it can be helpful to strengthen the hip and back muscles if you are kneeling due to a weakness in that area. For more tailored advice on a home exercise program feel free to book an online appointment with Click Phyiotherapy.
Bexters soda crystals:
Soda crystals can be one home remedy to trial for prepatellar bursitis. The theory is that the soda will help to suck the fluid out of the bursae via osmosis.
I have trialled this with patients and had varying degrees of success. The good news is that it’s very cheap to try and there’s no harm done if it doesn’t work.
If you wanted to trial Bexters soda crystals, I would recommend that you apply the crystals to your knee and wrap them in place with a bandage or cling wrap. Leave them overnight and be sure to sleep on a towel as you can often have excess moisture over night as the crystals draw out fluid.
Trial this for a week period and take note of the swelling before and after. If they have worked, you should see a notable reduction in the amount of swelling in the knee.
Self – massage:
Massage is another home remedy that has the same benefits that compression can have for knee bursitis. Gently rubbing the swollen knee can help to encourage fluid out and away from the swollen bursae.
Make sure that you don’t overdo it, massaging harder won’t do any good. This type of massage just encouraged fluid out of the joint and a gentle stroking from below the knee to above the knee is all that’s required. I would suggest you trail a 5-minute period, twice daily and see if you get results.
What about taping and bracing for knee bursitis?
Taping works very well for off-loading different structures in the knee. Unfortunately, bursitis is more a result of constant pressure so taping does not help to alleviate that pressure.
Wearing knee pads on the other hand can be very effective for relieving the pressure areas taking most of the load. If your job involves lots of kneeling such as tiling, roofing or carpet laying, then I would recommend looking into knee pads.
Knee braces can help to substitute for simple compression but I wouldn’t go out of my way to buy and expensive one.
The bottom line:
Knee bursitis needs to be defined from other common knee injuries and differentiated between septic bursitis and non-septic bursitis.
There are many different options for managing knee bursitis, but the best treatment is always prevention.
If you need further help and specific advice on your injury, please don’t hesitate to contact Click Physiotherapy for an online physiotherapy consultation.