Tendons are cords of connective tissue that connect muscles to bones. Sometimes tendons become strained and inflamed. This is known as tendonitis or tendinitis. Different tendons may be affected for different reasons and often this is related to specific actions and activities. One such instance is jumper’s knee where the tendon of the thigh muscles become inflamed. It is also known as patellar tendinitis.
What is jumper’s knee?
Jumper’s knee or patellar tendinitis is injury to the patellar tendon. This tends to arise with strain due to physical activities like jumping, hence the term jumper’s knee. However, jumper’s knee may arise with other strenuous activities that does not involve jumping such as running. It is one of the common tendon problems seen in the United States and affects as many as 1 in 5 athletes who participate in jumping activities.
There are various options for treating patellar tendinitis. In mild cases that do not recur, jumper’s knee can be managed conservatively with rest and cold therapy. Regular stretching and strengthening exercises is also helpful. Medication may be necessary and sometimes surgery is required to repair the tears, especially if there is a complete tear of the patellar tendon.
Causes of Jumper’s Knee
The patellar tendon runs from the bottom of the patella to attach to the shinbone. It is a continuation of the tendon that connects four thigh muscles (rectus femoris, vastus medialis, vastus lateralis and vastus intermedialis) to the top of the patella. These four muscles share a common tendon known as the quadriceps tendon. Although patellar tendinitis technicaly refers to the patellar tendon, the quadriceps tendon may also be involved. Patellar tendinopathy applies to a host of problems with these tendons.
In patellar tendinitis, tiny tears form in the patellar tendon due to the strain. This usually involves the posterior proximal fiber of the patellar tendon. A few minor tears may not cause any significant symptoms and the body can rapidly repair it. However, if the number of tears increases then the may be extensive inflammation of the tendon with a host of symptoms typical of patellar tendinitis. This is usually an acute problem but can persist for a few weeks, depending on whether the causative activity is discontinued or not and whether there is sufficient rest.
The exact cause of jumper’s knee is not fully understood. It is known to occur with repetitive stress by actions like jumping. Although more force is placed on the anterior fibers of the tendon during jumping, it is the posterior fibers that are more commonly affected in patellar tenditis. Microscopic examination does not indicate a significant presence of inflammatory cells which occurs with inflammation. It is therefore believed that jumper’s knee may not alway be a true tendinitis (inflammatory) but rather a tendinosis (degenerative).
Read more on kneecap pain.
Who is at risk of jumper’s knee?
Any person who is involved in repeated jumping may develop patellar tenditis. However, it also occurs with running. Therefore any repetitive stress injury of the knee and specifically the patellar tendon could be responsible for jumper’s knee. It is also more likely to occur with very forceful jumping or with infrequent running or jumping.
If the thigh muscles are not strong enough or tight then this can also contribute to jumper’s knee even with mild physical activities that are responsible for causing this condition. Uneven conditioning and strength of leg muscles can also increase the chance of jumper’s knee as some muscles pull more on the patella than other muscles.
Signs and Symptoms
The signs and symptoms of jumper’s knee usually develops gradually. However, excessive force placed on the tendon, especially if it is over a prolonged period of time may lead to a sudden onset of symptoms usually during or after the activity. A complete tear of the patellar tendon is possible but is more likely to occur with persistent or recurrent tendinitis without proper treatment and adequate rest.
- Pain and burning at the front of the knee, usually over the patellar tendon. This is located between the patella (kneecap or knee bone) and shin.
- Knee pain that is worsened by certain physical activities like jumping or running. Eventually the pain is even exacerbated by squatting or when standing from the sitting position.
- Tenderness over the affected area which may also be accompanied by swelling.
- Stiffness may sometimes be present, especially in the morning. However, the range of motion at the knee joint is usually normal.
- Tightness of the thigh muscles, particularly the hamstrings and quadriceps.
Read more on aching knee.
Stages of Patellar Tendinitis
The signs and symptoms of jumper’s knee can be divided into stages depending on the duration and severity. There are four stages of patella tendinitis that need to be considered when evaluating the condition.
Pain occurs only after activities like jumping and running. This does not impair a person in participating in the causative activities.
Pain during and after the activity but this does not restrict a person from participating in the activity. The pain usually resolves quickly with suitable rest.
Persistent pain during and after the activity which does not resolve quickly. It can impair a person from participating in a sport and hamper certain actions.
Complete tear of the patellar tendon. Surgery is required to repair the tendon.
Treatment of Jumper’s Knee
Treatment and management of jumper’s knee depends on the severity of the condition. Conservative measures like rest and exercise along with physical therapy may be sufficient in the early stages. Eventually medication may be necessary. Somtimes more invasive procedures are needed, especially surgery if there is a complete tendon tear.
Apart from stretching and strengthening exercises, other physical therapies may also be helpful. It is therefore important to consult with a physical therapist. If a physical therapist cannot be consulted with immediately then rest and applying ice packs after an injury will minimize strain and help reduce inflammation.
A number of different drugs can be administered. Some of these drugs can also be injected. These drugs include:
- NSAIDs such as ibuprofen or naproxen.
- Corticosteroid injections or topically with iontophoresis.
Surgery is useful in repairing the patellar tendon in chronic cases. It is necessary if there is a complete tear of the tendon.