“A bursa is a thin sack filled with synovial fluid, the body's own natural lubricating fluid. This slippery sack allows different tissues such as muscle, tendon, and skin slide over bony surfaces without catching. Your bursa essentially reduces the friction between structures. 

A bursa is normally very thin, but they can become inflamed and irritated. This is what is known as bursitis.  

Knee bursitis can cause pain above, on or below your patella (kneecap). The bursae most commonly subjected to inflammation are the prepatellar bursa, infrapatellar bursa, pes anserinus bursa and suprapatellar bursa. 

The infrapatellar bursa essentially consists of two bursae, one of which sits superficially between the patella tendon (below the kneecap) and the skin and the second referred to as the deep infrapatellar bursa is sandwiched between the patella tendon and tibia bone (shin). It can occur conjunctively with a condition called “Jumper’s Knee”, which involves repetitive strain and irritation to the patella tendon, often from jumping activities. 

There are a myriad of factors that can contribute to knee bursitis. The most common ones include:

• Direct trauma or blow to the knee.

• Frequent falls on the knee.

• Repeated pressure on the knee (eg from activities that entail prolonged periods of kneeling) or repetitive minor trauma to the knee.

• Knee Arthritis, thus bursitis can be associated with such conditions as gout, rheumatoid arthritis, and osteoarthritis. 

The symptoms of knee bursitis include:

• Swelling over, above or below the kneecap.

• Limited motion of the knee.

• Redness and warmth at the site of the bursa.

• Painful movement of the knee. 

Knee bursitis swelling is within the bursa, not the knee joint. People often call any swelling of the knee joint "water on the knee," but there is an important difference between fluid accumulation within the bursa and within the knee joint. 

Symptoms of knee bursitis are usually aggravated by kneeling, crouching, repetitive bending or squatting and symptoms can be relieved when sitting still. 

Your physiotherapist will provide you with a thorough quiz of your medical history and a physical examination of your knee to determine if you have knee bursitis. If there is localised swelling and you feel tenderness over the bursa when pressure is applied, a diagnosis is confirmed. With respect to scans, an MRI or Ultrasound are the most effective for a definitive diagnosis of knee bursitis. 

The diagnosis is the easy part. Your physiotherapist will also undertake a biomechanical analysis to determine what the cause of your bursitis actually is. Factors may include muscle weakness, tightness, pain inhibition, leg length discrepancy, training techniques and more.  

Many patients with knee bursitis start to feel better within a few weeks of the injury. Your physiotherapy treatment will aim to:

• Reduce pain and inflammation, this is achieved with the application of electrical modalities, ice, therapeutic taping and education regarding activity modification

• Normalise your knee joint range of motion.

• Strengthen your knee muscles: quadriceps and hamstrings.

• Strengthen your lower limb: calves, hip and pelvis muscles.

• Normalise your muscle lengths.

• Improve your proprioception, agility and balance.

• Improve your technique and function eg walking, running, squatting, hopping and landing.

• Minimise your chance of re-aggravation.

For more advice, please consult your physiotherapist.” 

https://physioworks.com.au/injuries-conditions-1/pre-patella-bursitis 

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