Patellar tendonitis is an injury to the tendon connecting the kneecap (patella) to the shinbone (tibia). The patellar tendon works with the muscles at the front of the thigh to extend the knee for kicking, running and jumping.
Patellar tendonitis, also known as jumper’s knee, is most common in athletes whose sports involve frequent jumping — such as basketball and volleyball. However, even patients who don’t participate in jumping sports can get patellar tendonitis.
Patellar tendonitis is a common overuse injury, caused by repeated stress on the patellar tendon. The stress results in tiny tears in the tendon, which the body attempts to repair. But as the tears in the tendon multiply, they cause pain from inflammation and weakening of the tendon. When this tendon damage persists for more than a few weeks, it’s called tendinopathy.
A combination of factors may contribute to the development of patellar tendonitis, including:
- Physical activity – Running and jumping are most commonly associated with patellar tendonitis. Sudden increases in how hard or how often the patient engages in the activity also add stress on the tendon, as can changing running shoes.
- Tight leg muscles –Tight thigh muscles (quadriceps) and hamstrings, which run up the back of the thigh, can increase strain on the patellar tendon.
- Muscular imbalance – If some muscles in the legs are much stronger than others, the stronger muscles could pull harder on the patellar tendon. This uneven pull could cause tendonitis.
Signs & Symptoms
Pain is the first symptom of patellar tendonitis, usually between the kneecap and where the tendon attaches to the shinbone (tibia).
The pain in the knee may:
- At first be present only as physical activity begins or just after an intense workout
- Worsen until it interferes with playing the sport itself
- Eventually interfere with daily movements such as climbing stairs or rising from a chair
During the clinical examination, pressure may be applied to parts of the knee to determine where is the pain. Usually, pain from patellar tendonitis is on the front part of the knee, just below the kneecap.
One or more of the following imaging tests may be suggested:
- X-rays – X-rays help to exclude other bone problems that can cause knee pain.
- Ultrasound – This test uses sound waves to create an image of the knee, revealing tears in the patellar tendon.
- Magnetic resonance imaging (MRI) – MRI uses a magnetic field and radio waves to create detailed images that can reveal subtle changes in the patellar tendon.
For knee pain, try self-care measures first, such as icing the area and temporarily reducing or avoiding activities that trigger symptoms.
See a doctor if the pain:
- Continues or worsens
- Interferes with ability to perform routine daily activities
- Is associated with swelling or redness about the joint
Doctors typically begin with less invasive treatments before considering other options, such as surgery.
Pain relievers such as ibuprofen (Advil, Motrin IB, others) or naproxen sodium (Aleve, others) may provide short-term relief from pain associated with patellar tendonitis.
A variety of physical therapy techniques can help reduce the symptoms associated with patellar tendonitis, including:
- Stretching exercises – Regular, steady stretching exercises can reduce muscle spasm and help lengthen the muscle-tendon unit.
- Strengthening exercises – Weak thigh muscles contribute to the strain on the patellar tendon. Exercises that involve lowering the leg very slowly after extending it are particularly helpful.
- Patellar tendon strap – A strap that applies pressure to the patellar tendon can help to distribute force away from the tendon and direct it through the strap instead. This may help relieve pain.
- Iontophoresis – This therapy involves spreading a corticosteroid medicine on the skin and then using a device that delivers a low electrical charge to push the medication through the skin.
If conservative treatments don’t help, suggested other therapies are:
- Corticosteroid injection – An ultrasound-guided corticosteroid injection into the sheath around the patellar tendon may help relieve pain. But these types of drugs can also weaken tendons and make them more likely to rupture.
- Platelet-rich plasma injection – This type of injection has been tried in some people with chronic patellar tendon problems. Studies are ongoing. It is hoped the injections might promote new tissue formation and help heal tendon damage.
- Surgery – In rare cases, if other treatments fail, surgical repair of the patellar tendon may be suggested. Some procedures can be done through small incisions around the knee.