What is jumper’s knee?
With jumper’s knee, you experience problems with the patellar tendon that runs across the knee joint. This tendon plays an important role in straightening the knee and absorbs a lot of force during movement, jumping, and pushing off. Due to repeated strain, this tendon can become irritated or damaged, leading to complaints known as jumper’s knee or patellar tendinopathy.
Location of the patellar tendon and kneecap
The patellar tendon runs from the shinbone upward toward the kneecap. The patella (kneecap) is embedded within this tendon. This creates a strong connection between the thigh muscles and the lower leg, but also makes the tendon sensitive to overload during intensive or repetitive movements.
Inflammation of the patellar tendon (tendinitis)
With overload, the patellar tendon can become inflamed. This is called tendinitis. It involves irritation and inflammatory reactions in the patellar tendon, often causing pain below the kneecap, especially during or after activities such as jumping or climbing stairs.
Degeneration of the patellar tendon (tendinosis)
Besides inflammation, the patellar tendon can also gradually deteriorate without a clear inflammatory response. This is called tendinosis. In tendinosis, the structure of the tendon changes and weakens, reducing its load capacity and allowing complaints to persist for a long time.
Development of jumper’s knee
When these changes occur in the patellar tendon, a so-called jumper’s knee develops. This tendon injury often develops gradually, without a clearly identifiable moment of onset. In that case, it is referred to as idiopathic onset, where symptoms slowly build up due to repeated strain.
How does jumper’s knee develop?
In many cases, the patellar tendon becomes overloaded without a direct trauma. Symptoms develop gradually due to repeated and often improper loading. Tiny microtears form in the tendon while the body does not get enough time to recover. As a result, the quality of the tendon decreases, which can lead to pain below the kneecap. This often occurs during sports.
Symptoms of jumper’s knee
- Pain at the lower side of the kneecap
- Pain when jumping, running, or climbing stairs
- Stiffness or tenderness around the patellar tendon
- Increase of symptoms during or after activity
- Reduced strength and confidence in the knee