Patellar tendonitis: Causes, Symptoms, and Treatment

The kneecap, or patella, is a triangular, disc-shaped flat bone viewed from the front, which is part of our knee joint and plays a vital role in the mobility and strength of our knee. Like almost any other organ, the kneecap can become inflamed and cause patellar tendonitis. This can lead to considerable pain and restricted movement in the knee joint.

The kneecap is connected to the large thigh muscle, the Musculus Quadriceps femoris, in whose tendon it is firmly anchored and serves as a sesamoid bone. 

The function of a sesamoid bone is to create an additional distance to the bone (in this case to the thigh) and thus a higher level for the tendon of the muscle so that the muscle has to use less force to move the bone. This is why you can build up so much strength with the thigh muscle via the knee joint. The rear surface of the kneecap is covered with cartilage to allow the knee joint to slide smoothly.

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Symptoms of patellar tendonitis

The main symptom of an inflammation of the knee joint is knee pain, especially in the front part of the knee joint and above/below the kneecap directly.

Typical signs of inflammation may also be present, such as overheating of the knee joint, more or less severe reddening of the skin around the kneecap, swelling of the entire knee joint. After sitting for a long time in a position with bent knees, it is difficult for the affected person to get up, and the pain becomes more durable for a short time. Continuous movement helps to relieve the pain.


The most frequent cause of patellar tendonitis is overloading. Often the cartilage substance is also affected. Through much running, running or jumping, strong mechanical impact and pressure forces act on our knee, which can lead to irritation or inflammation of the patella. This can occur acutely due to excessive strain, or can also take a chronic course.

If the kneecap is unfortunately hit by a hard impact so that the sliding movement in the knee cannot cushion it, the cartilage can be damaged, and the kneecap is squashed.

An inflammation of the patella can also accompany cartilage degeneration or knee arthrosis. In this case, the disturbing sliding friction on the underside of the patella due to the damage to the cartilage causes nerve irritation, which is perceived as pain. Besides, inflammatory processes in or on the patella produce metabolic products that have to be cleared away by the body’s immune cells, causing fluid to collect in the knee.

The so-called patellar tip syndrome is a quite common pathological and inflammatory disease of the kneecap, which is also caused by unfavorable stress.

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Patellar Tip Syndrome

An inflammation initially manifests itself in pain and visible redness.

In patellar tendonitis, severe knee pain is caused by chronic overloading of the extensor apparatus of the patella. This is caused by a frequently recurring tensile stress that is unusual for the knee, such as that which occurs mainly in jumping sports. This is why the term “Jumper’s Knee” is used – also a synonym for the patella tip syndrome. Beginners, in particular, are at risk of developing the described symptoms if they quickly strain the knee unprepared.

Patellar tendonitis is usually treated conservatively. The most important thing is to stop the triggering strain for at least six weeks. After that, the load can slowly be regained. Also, anti-inflammatory drugs such as ibuprofen can be taken.

Diagnosis of patellar tendonitis

The clinical examination mainly makes the diagnosis of patellar tendonitis of the knee. For this purpose, the knee is inspected for redness and malpositioning and then examined for movement restrictions, pressure pain, and overheating.

Imaging procedures, such as X-rays or magnetic resonance imaging (MRI) of the knee, can also help make a diagnosis.


The therapy of patellar tendonitis can be carried out conservatively. The most important measure is to relieve the knee and avoid strong impact and pressure forces on the knee. Also, non-steroidal anti-rheumatic drugs, such as ibuprofen or diclofenac, can be used to treat the pain and inflammation.

Another therapy option would be the use of cortisone injections into the affected joint to locally counteract the inflammation. Physiotherapy can also be useful, as can heat or cold therapy, depending on the stage of the inflammation.

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