“Jumper's knee”, or patellar tendinitis

Symptoms of jumper's knee

The first symptom is pain. It is usually located between the kneecap and the point where the tendon attaches to the shinbone (tibia).

At first you may only feel pain in your knee when you start training or immediately after an intense session. Over time this worsens and begins to interfere with sporting activity. Eventually the pain hampers everyday movements, such as climbing stairs or getting up from a chair.

When to see a doctor?

With knee pain, first try home self-care measures, for example icing the area and temporarily reducing or avoiding the exercises that trigger symptoms.

See your doctor if your pain:

• is constant or gets worse;
• prevents you from performing routine daily activities;
• is accompanied by swelling or redness around the joint.

Causes of jumper's knee

Jumper's knee is a common overuse injury caused by repeated loading of the patellar tendon.

Because of the load, tiny tears develop in the tendon, which the body attempts to repair. However, as these tendon tears accumulate they cause pain due to inflammation and weakening of the tendon.

If the tendon injury persists for more than a few weeks, it leads to structural changes in the tendon (this condition is called tendinopathy).

Risk factors

A combination of factors can contribute to the development of jumper's knee, including:

• Physical activity: running and jumping are the most common causes. A sudden increase in the intensity or frequency of activity can also overload the tendon. Even changing running shoes and altered support can trigger it.
• Relative muscle weakness: heavy strengthening exercises for the thigh muscles place great load on the quadriceps and indirectly on the tendon. Poorly chosen weight or incorrect movement (squatting too deep), and repeated landing after weighted jumps chronically overload the tendon.
• Tight leg muscles: tight quadriceps and hamstrings can increase the load on the patellar tendon.
• Muscle imbalance: if some muscles in your leg are much stronger than others, the stronger muscles can pull the patellar tendon more. This uneven pull can also cause an overuse inflammation.
• Chronic disease: certain diseases impair the blood supply to the knee, weakening the tendon. Examples include kidney failure, autoimmune diseases such as lupus or rheumatoid arthritis, and metabolic diseases like diabetes. Steroids used for these conditions can further weaken tendon structure.

Complications

If you continue to load the tendon despite the pain, ignoring your body's warning signs, you can cause progressively larger tears in the patellar tendon. If left unaddressed, inflammation becomes more pronounced and persistent. Slow degeneration and deterioration of the tendon reduce its elasticity and tensile strength, and the process can even end in tendon rupture.

Prevention

You can reduce the risk of developing jumper's knee with the following steps:

• Don't play through the pain: as soon as you notice knee pain related to training, ice the area and rest. Until your knee is pain-free, avoid activities that load the patellar tendon.
• Strengthen your muscles: strong thigh muscles tolerate load better. Eccentric strengthening exercises (slowly lowering the leg under load after knee extension) are particularly useful.
• Improve your technique: since incorrect movement can lead to jumper's knee, consult a movement therapist and analyze your movement. Refining your technique can help a lot.

Diagnosis

During the exam your doctor will palpate parts of your knee to determine where it hurts. Pain from patellar tendinitis typically appears in the front of the knee, directly below the kneecap. In most cases the diagnosis is made by an experienced physician based on symptoms and physical examination.

So-called imaging studies can help confirm the diagnosis:

• X-rays: X-rays help rule out other bone problems that can also cause knee pain.
• Ultrasound: this test uses high-frequency sound waves to image the knee and can reveal small tendon injuries, tears, and swelling caused by inflammation.
• Magnetic resonance imaging (MRI): can reveal subtle tendon changes in great detail.

Treatment

Medical treatment for jumper's knee usually starts with the less invasive options. Physical therapy and stretching and strengthening the muscles around the knee play a prominent role.

Medications and other methods

• Pain relief can alleviate the pain of patellar tendinitis in the short term, but these do not have an anti-inflammatory (healing) effect.
• Corticosteroid injection: an ultrasound-guided corticosteroid injection into the sheath around the patellar tendon can help relieve pain. However, steroids weaken tendons and therefore increase the likelihood of rupture.
• Platelet-rich plasma injection: already tried in patients with chronic patellar tendon problems; evaluation of study results is ongoing. It is hoped these injections may promote new tissue formation, tissue regeneration, and thus help tendon injuries heal.

Physio- and physical therapy

Several physical therapy techniques can help reduce the symptoms of jumper's knee, including:

Stretching

Regular stretching of the leg muscles (primarily quadriceps and hamstrings) reduces muscle stiffness and helps restore disturbed muscle balance.

Strengthening the thigh muscles

Weak thigh muscles contribute to loading the patellar tendon. Since strengthening the quadriceps (e.g. with weights) may not be possible with a painful knee, muscle stimulation of the thigh muscles can be considered for jumper's knee. Exercises combining stimulation with bodyweight are most effective, but stimulation alone also helps.

Click here for a complete stimulation training plan to strengthen your quadriceps.

Microcurrent treatment

Microcurrent treatment is an effective anti-inflammatory procedure that is suitable for treating tendon inflammation. The devices below include programs for “Tendon inflammation”, “Patellar tendon inflammation” and “Achilles tendon inflammation”. Use these programs.

Click here to read how to perform microcurrent treatment.

I recommend these devices for treating tendon inflammation: Soccer Pro, Runner Pro, Cycling Pro, Premium 400

Iontophoresis

For athletes' tendon inflammation, steroid agents that cannot be given orally (they are often classified as doping substances) can be administered locally by iontophoresis, which can be performed with the IontoBravo iontophoresis device. In iontophoresis the corticosteroid medication is applied to one electrode and then introduced through the skin directly into the joint using a mild electric current.

Therapeutic ultrasound

Therapeutic ultrasound relaxes and warms the tendon and increases its blood circulation. Pain and inflammatory symptoms ease, and healing accelerates. Daily 8–10 minute treatments are needed for 15–20 days. Suitable device: M-Sonic 950 therapeutic ultrasound

Soft laser treatment

The soft laser beam has a twofold effect on the tendon. On one hand it warms the tissue and increases blood flow, which relieves pain and inflammatory symptoms. On the other hand it works at the cellular level, increasing ATP (energy) production in cell mitochondria. Better energy supply further speeds healing. Daily 3–5 minute treatments are needed until full recovery.

Recommended device: Personal Laser L400 softlaser

Surgical procedures

If conservative treatments do not help, further interventions may be considered, such as:

• Percutaneous ultrasonic (oscillating needle) procedure: this outpatient treatment is performed under local anesthesia. Using ultrasound guidance, a device is directed to the tendon. The oscillating needle removes the damaged tissue while sparing healthy tendon. This is a relatively new procedure not yet widely available, but results so far have been promising.
• Surgery: in rare cases, if other treatments fail, the patellar tendon may be surgically removed, which can end your sports career. Therefore strive to avoid surgery.