What Is Patellar Tendinopathy?

Patellar tendinopathy (also known as jumper’s knee and patella tendinitis) is a common soft tissue injury which causes significant pain in the tendon on the front of the knee, below the knee cap (known as the patella). It can also cause stiffness and weakness around the knee. The pain is particularly noticeable in the morning and getting up after sitting for a while, for example, after driving or sitting in a cinema.

It is sometimes called ‘jumper’s knee’ because the injury often happens during sports that involve jumping, such as volleyball and basketball. 

The patellar tendon works with the muscles at the front of your thigh (quadriceps) to straighten your knee so that you can kick, run and jump. Patellar tendinopathy occurs when the patellar tendon is overused /overloaded. The tendon struggles to cope with the pressure put upon it resulting in micro-injuries and weakening of the structure; this causes swelling of the tendon and consequently pain. The process can occur over many months or can happen rapidly with one bout of intense exercise.

Anatomy of Patellar Tendinopathy

The patella tendon is located just below the patella (knee cap), and it has attachments on the patella and the tibia (shin bone). The role of the patella tendon is to transfer the force of the quadriceps muscles via your patella and your upper tibia.

The quadriceps muscles, quadriceps tendon, patella and patellar tendon are responsible for extending (straightening) your knee during running and jumping and are collectively known as the knee extensor mechanism.

Your quadriceps are even more critical when controlling your knee as you bend from a straight position, e.g. walking down stairs and landing from a jump. Your quadriceps muscles are heavily involved in most sports, especially jumping, running and kicking.

What Causes Patellar Tendinopathy?

The role of a tendon is to withstand high, repetitive loading; however when the patellar tendon is subjected to excessive, high-intensity activity involving jumping, running or other heavy load, it can place excessive strain on the patella tendon.

When tendons become strained, they sustain small micro-tears, which causes inflammatory chemicals and swelling (tendonitis); quickly healing if managed appropriately with rest i.e. a reduction of the high impact forces. However, repeated bouts of overstrain to your tendon causes increased microtrauma. This ongoing trauma occurring in the tendon can exceed the rate of repair, resulting in an incomplete, sub-optimal healing response. At first, the damage may only be minor and not cause any problem, but damage will progressively become worse, causing the tendon to become more inflamed and thickened, which results in significant pain and dysfunction. This is patellar tendinopathy and in severe cases can result in larger tears or even tendon rupture.

This injury usually happens gradually over time. Researchers in this field still have unanswered questions about how or why patellar tendinopathy occurs, but there appear to be two main types of issues:

  1. Problems with tendon loading – sudden changes in tendon loading. Such as starting to train at the beginning of a sports season or increasing your running training too quickly. This type of tendinopathy is more common in patients aged 15-30. Men are also more likely to be affected.
  2. Problems with the health of the tendon – this usually affects older adults (over 35) as their tendons degenerate and become more rigid and stiff. This is part of the normal ageing process. Genetics, smoking and some medical conditions can also affect the health of this tendon.

Risk Factors for Patellar Tendinopathy?

A combination of factors may contribute to the development of patellar tendinopathy, including:

Training/activity level

This can occur in a variety of ways. For example:

  • A rapid increase in the amount of training – how often you are training/playing.
  • A sudden increase in training intensity – how hard and long you are training/playing for.
  • Poor technique – If the way you are running/jumping/landing is not correct, you could put increased pressure through your patella tendon.
  • Training/playing on rigid surfaces – this will cause increased impact going through the patella tendon.

Poor Flexibility

Tight quadriceps and/or hamstring muscles can increase the strain on your patellar tendon

Lower Limb Biomechanics

Biomechanical issues can include muscle imbalances, poor foot posture, structural abnormalities, or poor knee or hip control.

Your physiotherapist will assess this and treat these issues as required. Changing your footwear can also contribute to the

Chronic illness/health

Some illnesses disrupt blood flow, which can cause weakness in the tendons around the body (including the patella tendon). Examples include kidney failure, autoimmune diseases such as lupus or rheumatoid arthritis and metabolic diseases such as diabetes.

Patella tendinopathy has also been associated with a high body mass index (BMI) or sudden weight gain.

What are The Symptoms of Patellar Tendinopathy?

The main symptom of patellar tendinopathy is pain, or aching, just below your kneecap. You’ll probably start to notice a gradual increase in pain, rather than having an injury that suddenly causes it. When you first feel pain, it will probably only come on after you exercise. As time goes by you may feel pain during exercise, which gets less after you warm up. This may then develop into constant pain for the duration of the activity. As well as being painful, your knee may be tender to the touch.

Symptoms often present gradually, without trauma, and can take weeks or months of repetitive overloading before becoming problematic. They can also come on more quickly if you have suddenly upped your training/activity level.

If you don’t have treatment for patellar tendinopathy, there’s a possibility that your tendon will eventually tear or rupture. If this happens, you may have sudden pain and your knee may give way.

Common Signs and Symptoms of Patellar Tendinopathy:

  • Pain/dull ache over the front of the knee below the knee cap.
  • Pain is made worse with jumping, landing or running activity.
  • Pain with negotiating stairs and inclines.
  • Localized tenderness over the patella tendon (painful to touch)
  • Often the tendon feels very stiff first thing in the morning or after periods of rest such as rising from sitting at your desk.
  • Delayed pain that comes on sometime after a period of activity.
  • The affected tendon may appear thickened in comparison to the unaffected side

If you are experiencing any of these symptoms in your knee, please book an appointment to see one of our expert physiotherapists.  The team at Physiohaus is able to diagnose and treat your knee pain to help you return to the activities that you love.