In this article you will find out about the most common causes of infrapatellar bursitis and the most effective ways to treat it.
There are many bursae present throughout the body. They are sac-like structures filled with synovial fluid. The main function of the bursa is to provide a cushioning effect to the structures underneath it, hence giving the musculoskeletal system mobility. The knee is the main weight-bearing joint which is surrounded by many ligaments, soft tissue structures, and a knee cap; the patella. In the body and there are four main bursae located around the knee joint held together by a patellar tendon; suprapatellar, infrapatellar, prepatellar, and pes anserine. Inflammation of any of these bursae results in knee bursitis which is accompanied by extreme knee pain and problems in walking.
Infrapatellar bursitis is a condition of the knee that involves swelling and pain under, above, and below the knee cap region, also called the patella. This type of inflammation is also known as the ‘Clergyman’s knee.’ There are many possible reasons that can cause this condition; such as injury to the area, infection, or overuse of the knee joint. 
There are many bones present in the knee joint, and hence in order for the joint to function without a lot of friction, there are many bursae around the patella. The infrapatellar bursa is located beneath the patella/kneecap and lies at the patellar tendon. This bursa is composed of two sacs. One sac lies more superficially and is hence called the ‘Superficial Infrapatellar bursa,’ whereas the other sac lies deep to the patella tendon, close to the tibial bone, and is called the Deep infrapatellar bursa.
Causes of Infrapatellar Bursitis
Whenever the thin sac of the bursa surrounding the knee joint suffers in any form, there is inflammation. This inflammatory process results in excessive fluid being produced inside the sacs of the infrapatellar bursae of the knee joint, causing irritation and knee pain. There are many factors that can cause infrapatellar bursitis, some of them have been listed below; 
Oftentimes superficial infrapatellar bursitis is due to direct trauma to the knee cap. This injury leads to rupture of the vessels that ultimately bleed into the bursa. Athletes are very prone to knee injuries, therefore the incidence of superficial infrapatellar bursitis increases twofold from their DOI. People who have bleeding disorders might end up with haemorrhagic superficial infrapatellar bursitis suddenly.
Chronic microtrauma can also be a risk factor for superficial infrapatellar bursitis. This results in the constant friction being produced between the patella, and the tibia.
Other forms of superficial bursitis include prepatellar bursitis, which is also known as the housemaid’s knee or the carpet layer’s knee. This name is derived from the understanding of knee joints being overused. Hence, professions that require work to be done on the knees are often the ones suffering from these inflammatory conditions.
Overuse as a cause of infrapatellar bursitis
There are a lot of conditions that can cause the infrapatellar bursa to get swollen due to frequent activities that require the bending of the knees. These activities can range from; running, jumping, playing football, climbing up and down the stairs, etc.
Underlying knee conditions
Many times infrapatellar bursitis develops secondary to an already existing joint problem of the knees. These lesions can be of any type which eventually affects the bursa lying close to the patella and the tibia. Lesions occurring in the patellar tendon commonly called the patellar tendinopathy or the Jumper’s knee can end up affecting the other adjacent bursae and hence also cause infrapatellar bursitis.
Inflammatory, osteoarthritis, and rheumatoid arthritis can also progress to develop infrapatellar bursitis if proper medications are not taken.
Septic infrapatellar bursitis
Organisms gaining entry inside the bursa can very easily cause septic bursitis. Infection can be introduced to the sites of the infrapatellar bursa through two sources. It can either be due to a superficial cut or mark that can cause a break in the skin barrier and give organisms a chance to inoculate inside the bursae. It can also be due to an infection in the deeper soft tissues and ligaments, traveling by blood and reaching the site of the knee joint, resulting in an inflamed bursa. Septic bursitis can either be acute, recurrent, or chronic.
The most common bursitis at the knee joint is prepatellar bursitis. It is essential to get aspiration done from the inflamed bursa and get its fluid analysis done. This helps trace the organism causing the infection, and hence treated accordingly with the right cover of antibiotics. 
Symptoms of Infrapatellar Bursitis
The symptoms of infrapatellar bursitis progressively increase with time. It takes over months for all the symptoms to align with the inflammatory condition.
Swelling around the knee pads
One of the most prominent signs of infrapatellar bursitis is swelling just above the knee cap. This swelling is soft on the touch but extremely tender, called a cyst. The collection of infiltrates from the trauma/infection is what forms this pouch around the knee joint.
One of the most classical symptoms of infrapatellar bursitis is knee pain. It is felt all around the knee and extends below the knee pads. The pain is seen to get worse as the knee joint is bent. Activities such as climbing the stairs or kneeling are extremely painful. The reason for the extreme pain is due to the compression of the infrapatellar bursa and the soft tissues surrounding the patella.
Redness and warmth
Whenever there is an inflamed bursa, the skin overlying gets warm and red in colour. People who suffer from septic infrapatellar bursitis.
Knee joint rigidity
Due to the damage to the soft tissues and the bursa around the knee joint, it gets very hard to bend the knee. There is a rigidity and stiffness felt during flexion of the knee joint, this also leads to the weakness of the joint, as the capsule of the inflamed bursa swells up.
Fever as a symptom of infrapatellar bursitis
People who suffer from septic infrapatellar bursitis also come with complaints of fever and increased leukocytic count due to the organisms harbouring inside their knee joints.  
Diagnosis Infrapatellar Bursitis
There are a number of differential diagnoses established whenever a patient presents with signs and symptoms of infrapatellar bursitis. It is important to not just form a distinction between septic infrapatellar bursitis and other forms causing an inflamed bursa. Conditions such as joint effusions, osteoarthritis, cellulitis, septic, and inflammatory arthritis are the ones that present very much like infrapatellar bursitis and hence need proper evaluation. The tests that help with such distinction are mentioned below;
It is an X-ray of the anterior knee that can help with the diagnosis of infrapatellar bursitis due to any kind of knee injury that could have taken place. Any fracture, joint deformity, calcification, or any foreign body is detected on an x-ray. If there are no positive findings seen in an x-ray, then the person is sent to get an ultrasound done of the lesion. A Doppler Ultrasound is the radiological test of choice to investigate the contents of the inflamed bursa. 
It is important to get the blood tested for the number of leukocytes. An increased amount of leukocytes indicates an infection and hence needs further evaluation by joint aspirate.
This is a very important diagnostic test that helps differentiate between aseptic and septic bursitis. Some amount of fluid is aspirated from the inflamed bursa which is then examined, and the formation of crystals or presence of bacteria is then noted through this test.
Conditions that appear like Infrapatellar Bursitis
Differential diagnosis of a person presenting with knee bursitis is quite long. This is due to the many structures and bursae occupying the area of the knee joint. following is the list of conditions that have the same symptoms as presented with clergyman’s knee;
- Prepatellar bursitis or also known as housemaid’s knee
- Rheumatoid Arthritis
- Patellar tendinitis
- Patellar bursitis
- Pes anserine bursitis
- Calcification of the knee joint
Treatment of Infrapatellar Bursitis
The infrapatellar bursa has a poor blood supply, which is why it can struggle to heal its own. It is the oxygen and nutrients in our blood supply that helps to heal and repair structures in the body.
Prolotherapy involves the injection of a regenerative solution into the bursa to provide it with a direct supply of what is required to heal and repair.
As the treatment is helping to treat the root cause of the problem, it is deemed to be a permanent fix.
The treatment of the clergyman’s knee consists of NSAIDs to help with the knee pain. Moreover, in order to decrease the extent of inflammation, corticosteroids are also used to manage the condition. However, those who get diagnosed with septic bursitis are given antibiotic therapy to get rid of the infection causing all the problems.
Physical therapy is advised to help the soft tissues recover and to increase the range of motion of the knee.   
Frequently Asked Questions –
How do you treat Infrapatellar bursitis?
It is treated by decreased strain or stress over the affected knee. NSAIDs and other anti-inflammatory drugs are prescribed to help with the pain. Physical therapy is encouraged to help ease flexion of the knee joint. Steroid injections are also used to help manage inflammation.
How long does Infrapatellar bursitis last?
It can take weeks to months for infrapatellar bursitis to completely subside. However, it normally takes about a month for all the symptoms to resolve.
How painful is Infrapatellar bursitis?
This condition is extremely painful especially when the knee is flexed. Therefore, walking, and climbing the stairs can cause a lot of pain. However, there is only mild pain felt when the person is resting or not performing any activity.
How long does it take to recover from patellar bursitis?
It has been seen that patellar bursitis is less severe in nature and hence takes about 2-3 weeks to resolve.
Is it OK to walk with knee bursitis?
Rest is very important especially when a condition like knee bursitis has developed. A light walk will not cause a lot of harm but those affected with knee bursitis should avoid high-core exercises.
Is heat good for knee bursitis?
Dry or moist heat, such as taking a warm bath can help ease the pain.
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