Patellar tendinitis is an overuse injury that affects the tendon connecting your kneecap (patella) to your shinbone (tibia). The patellar tendon plays a pivotal role in the way you use your legs. It helps your muscles extend your lower leg so you can kick a ball, push the pedals on your bicycle and jump up in the air.
Patellar tendinitis occurs when you place repeated stress on your patellar tendon, often when you suddenly increase the intensity or frequency of your workouts. Stress causes tiny tears in the tendon, which your body attempts to repair. But as the tears in the tendon become more numerous, your body can't keep up, causing the inflammation in your tendon to worsen. Pain may be infrequent at first, but with continued stress and damage to the patellar tendon, the pain of patellar tendinitis can become a constant ache.
Patellar tendinitis is most common in athletes whose sports involve frequent jumping — for instance, basketball, soccer and volleyball players. For this reason, patellar tendinitis is commonly known as jumper's knee. However, since anyone can suffer from patellar tendinitis, whether they jump frequently or not, many doctors consider this term misleading. Terms used to describe recurring patellar tendinitis that causes further degeneration of the patellar tendon include patellar tendinopathy and patellar tendinosis.
Doctors aren't certain what causes patellar tendinitis. It's believed that a combination of factors could be involved, including:
When to seek medical advice:
- Stress on the patellar tendon. Repeated jumping is most commonly associated with patellar tendinitis. Sudden increases in the intensity of physical activity or increases in frequency of activity also put added stress on the tendon.
- Tight leg muscles. Reduced flexibility in your thigh muscles (quadriceps) and your hamstrings, which run up the back of your thighs, could increase the strain on your patellar tendon.
- Misalignment of your leg. The way your leg bones line up could be off slightly, putting strain on your tendon.
- Raised kneecap (patella alta). Your kneecap may be positioned higher up on your knee joint, causing increased strain on the patellar tendon.
- Muscular imbalance. If some muscles in your legs are much stronger than others, the stronger muscles could pull harder on your patellar tendon. This uneven pull could cause tendinitis.
If you experience knee pain, try self-care measures first. If pain continues, worsens or interferes with your ability to go about your day, call your doctor.
Pain is the first symptom of patellar tendinitis. The pain usually is located in the section of your patellar tendon between your kneecap (patella) and the area where the tendon attaches to your shinbone (tibia). During physical activity, the pain may feel sharp — especially when running or jumping. After a workout or practice, the pain may persist as a dull ache.
The pain in your knee may:
- Initially be present only as you begin physical activity or just after an intense workout
- Increase as you step up the intensity of your activity
- Progress to be present before, during and after physical activity
- Make going up and down stairs painful
- Become a constant ache that can make it difficult to sleep at night
Your doctor may be able to determine that you have patellar tendinitis based on your signs and symptoms. If the diagnosis isn't as clear, he or she may conduct tests to rule out other conditions. Tests and examinations might include:
A combination of tests may help your doctor rule out other conditions that can cause knee pain similar to patellar tendinitis, such as pain behind your kneecap (patellofemoral pain syndrome), tears in the meniscus that cushions your knee joint, and breakdown of the cartilage underneath your kneecap (chondromalacia patella).
- Physical exam. Your doctor may apply pressure to different parts of your knee to determine exactly where you're experiencing pain. Pain associated with patellar tendinitis usually concentrates on the front part of your knee, just below your kneecap.
- Squat test. In order to reproduce your pain, your doctor may ask you to do squats — a type of deep knee bend — either standing on both feet or on one foot. Your doctor pays close attention to how you perform the squat and whether you experience pain.
- Ultrasound. This test uses sound waves to create an image of your knee, revealing the location of tears in your patellar tendon.
- Magnetic resonance imaging (MRI). MRI uses a magnet to create images that are more detailed than ultrasound images. MRI can reveal more subtle changes in the patellar tendon.
Though pain is usually the first symptom of patellar tendinitis, it usually indicates that damage to your tendon is already significant. If you continue to work through the pain, ignoring the warning signs your body is sending you, you could cause even further tendon damage and other complications, such as:
- Weak leg muscles. As your leg compensates for the pain in your knee and the instability of your patellar tendon, your thigh muscles (quadriceps) and calf muscles can weaken.
- Torn tendon. Your body can't keep up with the continued wear and tear on your tendon, leading to larger and larger tears in the patellar tendon. Eventually the tendon could rupture, though a ruptured tendon is rare in chronic patellar tendinitis.
Treatment of patellar tendinitis is a long process, no matter what type of treatment you choose. Recovery can take a few weeks and up to a year for people who undergo surgery. Most people with patellar tendinitis find pain relief and improvement using conservative treatment — meaning treatments other than surgery. A small number of people who have persistent signs and symptoms may benefit from patellar tendinitis surgery.
The conservative approach to treating patellar tendinitis aims to reduce the strain on your tendon and then gradually build up the tendon's strength. Your doctor may use several techniques to accomplish this, including:
If you've recently developed patellar tendinitis, you can expect several weeks of conservative therapy before you'll be able to fully resume physical activity, including jumping. If you've re-injured your patellar tendon, the time for healing may be even longer.
- Rest. Rest doesn't mean giving up all physical activity, but avoid running and jumping. Your doctor can suggest other ways of staying active without stressing your damaged patellar tendon. It's especially important to avoid any activity that gives you pain.
- Adjusting your body mechanics. A physical therapist can help you learn to better distribute the force you exert during physical activity. For instance, an athlete who jumps frequently might learn proper jump take-off and landing techniques.
- Stretching your muscles. Inflexible muscles, especially inflexible thigh muscles (quadriceps), contribute to the strain on your patellar tendon.
- Strengthening your tendon. A physical therapist may recommend specific exercises to strengthen your patellar tendon. Exercises can also help strengthen your quadriceps.
- Patellar tendon strap. A strap that applies pressure to your patellar tendon can help to distribute force away from the tendon itself and direct it through the strap instead. This may help relieve pain.
- Massage. Massaging the patellar tendon, thigh muscles and calf muscles may help encourage tendon healing.
You and your doctor may consider surgery for your patellar tendinitis if more conservative approaches aren't working. There is little research into the best surgical techniques for patellar tendinitis, so often the procedure you undergo depends largely on your injury, as well as your surgeon's preferred method. Surgery may include repairing any tears in your tendon or removing any badly damaged parts of your tendon.
Expect several months of recovery after surgery. About a quarter of people who undergo surgery will still experience pain, and some people aren't able to return to their sport of choice after surgery.
Other types of therapy may provide relief from pain associated with patellar tendinitis. Though these methods haven't been thoroughly researched, your doctor might consider trying:
- Medications. It isn't clear if nonsteroidal anti-inflammatory drugs (NSAIDs) offer any relief from pain associated with patellar tendinitis. NSAIDS are usually used to relieve pain associated with inflammation, but chronic patellar tendinitis doesn't involve inflammation. Corticosteroids may be used for pain relief, though there's a concern that they could also weaken the patellar tendon.
- Other physical therapy treatments. This category includes treatments using ultrasound, laser and electrical stimulation. These can help to provide pain relief, though more research is needed to determine if they heal the tendon.