What are the forms of knee tendonitis?

By Cristiano Antonino Last updated Jun 20, 2023

Knee tendonitis is inflammation of one of the tendons in the knee, the joint that connects the thigh to the leg

The pathology arises due to a functional overload, a continuous repetition of a movement that causes a strong stress to the damage of the tendon, where an inflammatory process consequently develops.

Find out below the most common causes and symptoms of knee tendonitis, how the diagnosis is made and what are the recovery times and possible therapies.

What is knee tendonitis?

Knee tendonitis is a state of inflammation of the tendons that insert into the bone elements that make up the knee joint.

It should be remembered that a tendon is nothing more than a band of fibrous connective tissue composed mainly of collagen and with a certain elasticity.

Tendons have the function of joining skeletal muscles to bones, thus allowing movement.

Acute trauma or functional overload can cause tendonitis, which etymologically means “inflammation of a tendon”.

There are three main tendon structures in the knee joint:

The patellar tendon, which connects the lower part of the patella to the tibial tuberosity, i.e. the prominence of the distal-anterior portion of the tibia;
The quadriceps muscle tendon, which connects the quadriceps femoris muscle (which is the main muscle of the anterior thigh) to the top of the kneecap;
The tendon of the popliteus muscle, which connects the popliteus muscle (located in the posterior-superior portion of the leg) to the lateral condyle of the femur and the knee joint capsule.

There are 3 types of knee tendonitis possible:

Patellar tendinitis, which affects the patellar tendon;
Quadriceps tendinitis, which affects the tendon of the quadriceps muscle;
Popliteal tendinitis, which involves the tendon of the popliteus muscle.

Of the three, the first, i.e. patellar tendonitis, is undoubtedly the most common, especially in sports and among truck drivers or forklift drivers, and is also known as patellar tendonitis or “jumper’s knee”.

What are the most common causes?

In most cases knee tendonitis is caused by a functional overload, i.e. by a continuous repetition of a movement that stresses the tendon in a harmful way which, consequently, develops an inflammatory process.

Although it can affect anyone, the pathology is statistically more frequent among people who practice sports or do jobs that place particular stress on the knee joint.

Patellar tendonitis: subjects at risk

As the other name of patellar tendonitis, jumper’s knee, suggests, those who play sports that involve sudden changes of direction, leaps and jumps are more likely to develop patellar tendonitis, including: volleyball, soccer, basketball, athletics, etc. .

It is also common in people who perform jobs in which the patellar tendon is subjected to constant stress such as trucking or forklifting, who continuously stress the knee by acting on the pedals to control the vehicle.

Quadriceps tendonitis: subjects at risk

Even if the quadriceps tendon is very robust and hardly prone to developing inflammation, quadriceps tendonitis particularly affects people who practice sports in which they run at maximum speed alternating with sudden braking, jumps, leaps and bending on the legs.

Popliteal tendinitis: subjects at risk

Popliteal tendinitis, on the other hand, is much more common in runners or in those who usually go hiking in the mountains.

In particular, it is above all the downhill walk that can put the subject at risk of developing inflammation.

What are the symptoms and possible complications?

The symptoms of knee tendonitis vary depending on which tendon is affected by the inflammation.

However, symptoms such as pain, swelling, redness and heat are common to all three tendinitis.

Symptoms of patellar tendonitis

Typical symptoms of patellar tendon inflammation include:

Local pain, which tends to improve with rest and worsen when the joint is stressed during physical activity;
A sense of soreness below the knee;
Feeling of stiffness in the knee;
Thickening of the patellar tendon.

Symptoms of quadriceps tendonitis

Sufferers of quadriceps tendonitis usually experience pain in the lower thigh that tends to get worse when the knee is flexed.

In some cases, in the same area where the pain is located, the patient may notice swelling, soreness and a sense of warmth.

Symptoms of popliteal tendonitis

When the tendon of the popliteus muscle is affected by inflammation, the patient may experience: pain on the outside and in the back of the knee, swelling and redness on the outside of the joint, sensation of knee yielding and, in general, of joint weakness.

The symptoms of a popliteal tendinitis can worsen during flexion and extension movements of the knee

In the event that knee tendonitis is not treated adequately, it is possible the onset of some complications.

It is in fact possible that the inflammation worsens until it damages the tendon involved or, in the case of patellar tendonitis, until it breaks.

Complications could make knee tendonitis much more difficult to treat and require surgery.

For this reason, in the presence of pain in the knee area it is strongly recommended to stop the activity that could be the cause of tendonitis and consult a doctor.

How is knee tendonitis diagnosed?

A thorough medical history to establish the causes and factors that led to the inflammation, together with a thorough physical examination are usually sufficient to diagnose knee tendonitis.

Sometimes, however, the doctor may also request imaging tests to have a more precise clinical picture, among these:

Tendon muscle ultrasound, to analyze the health of the tendon and the muscle connected to it;
Magnetic resonance imaging, to have an accurate view of each component of the joint;
X-rays, needed if there is a suspicion of a bone problem related to tendonitis.

Once the clinical picture is clear, it will be possible to establish the most suitable therapy for the case.

Possible therapies to cure knee tendonitis

Usually the cure for knee tendonitis involves a conservative treatment.

First of all, functional rest of the affected limb is recommended, which consists in the total suspension of the activities responsible for the inflammatory condition.

Rest times vary depending on the case and the severity of the inflammation.

In general it is important to wait for the pain to go away completely.

The patient is also advised to apply ice packs to the painful area about 4-5 times a day for 15-20 minutes.

Ice has an anti-inflammatory and pain-relieving action and can be especially useful in the initial stages of the disease.

It could also be useful to use a compression bandage around the knee, to mitigate the pain and speed up healing.

In some cases, your doctor may prescribe non-steroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation and relieve pain.

Rarely, and only in cases where the symptoms persist and NSAIDs are ineffective, a local injection of corticosteroids is prescribed to the patient.

In the most serious cases it is necessary to resort to physiotherapy exercises for a complete recovery which include proprioceptive exercises, stretching and strengthening of the muscles of the suffering limb.

Instrumental therapies such as ultrasound, tecar therapy, Transcutaneous Electrical Nerve Stimulation (TENS), or iontophoresis can also be added to these therapies.

Surgery to treat knee tendonitis (arthroscopy) is generally very rare, even if it becomes an obligatory option when the painful symptoms persist for months and other treatments are insufficient, or when the pathology evolves into a more serious damage to the tendon.