Quadriceps Tendonitis

What is the quadriceps tendon?

The quadriceps is a group of muscles positioned at the front of the thigh and its notable functions include aiding with movements such as kicking, running, jumping and walking.¹ Tendons are bands of tissue grouped together that aid muscles to connect to the bone and the quadriceps tendon is located just above the patella (knee cap) on both legs.² The quadriceps tendon is formed by the four quadriceps muscles: the rectus femoris, vastus lateralis, vastus  mediali and the vastus intermedius, which are all positioned along the front of the thigh and attach together at the patella.³ 

The quadriceps muscles, the quadriceps tendon and the patellar tendon work simultaneously together to straighten the knee upon contraction.² If either the patellar or quadriceps tendons are damaged, this will mean that that muscle cannot anchor itself correctly to the kneecap, provoking pain as the knee can longer extend fully (knee extension and knee flexion).² Quadriceps tendon can rupture and this has a prevalence of 1.37 per 100,000 worldwide; most commonly caused by falls and the treatment includes a surgical repair technique using patella drill holes.⁴

What is quadriceps tendonitis?

If we break the word tendonitis down etymologically, we can see two words, “tendon” and “itis”. The suffix “itis” in medicine refers to an inflammation, so in this case the quadriceps tendon is inflamed.⁵ Causes of the inflammation or swelling are unknown, however there are certain triggers, according to the Arthritis Foundation, including⁶

• Bad gait pattern
• Overuse through sport
• Repetitive movements
• An infection
• Some types of arthritis
• Metabolic conditions e.g., diabetes 
• Stress on soft tissue due to poor alignment of the joint e.g., joint deformities

Anatomically speaking, it is usually caused by overuse or overloading of the extensor mechanism, in either a flexed or hyperflexed position, in a planted foot and is prevalent in athletic individuals under the age of 40.⁷

Is tendinitis the same as tendonitis?

Both refer to the same condition, they are just different variants of the same name.

Signs and symptoms

The potential signs and symptoms of quadriceps tendonitis are as follows:^9,10

• Burning sensation at bone-tendon junction
• Pain aggravated by activities that require extending the  knee e.g bending ,jumping , walking
• Inability to fully extend the knee
• A popping sound or clicking of the knee
• Pain along the top of the kneecap
• Tenderness at the kneecap upon touching
• Stiffness after exercise 
• Aches upon standing from a squatted position

If you have  any of the above symptoms, then a doctor should be contacted in order to give you the correct diagnosis and course of treatment. Typically, a specialist may recommend that you visit a physiotherapist in order to strengthen the tendon so that it can be brought back to normal functioning without pain. 

Causes and risk factors

The main cause of this injury is a microtrauma caused by overusing the tendon and this can be through activities such as: 

• Running
• Frequently kneeling or squatting
• Climbing stairs amongst others⁹   

A variety of risk factors exist for developing quadriceps tendonitis. In 2019, a study deduced that the main risks include age, birth gender, static and dynamic properties of the ankle, alochol use and use of ofloxacin (used to treat bacterial infections).¹¹  

A cohort study in 2013 found that the statistical odds of developing the injury increased amongst a younger demographic. Those born in 1980 had an odds of 38% of developing the disease whilst those born in 1960 had an odds of only 20%.¹² It could therefore be deduced that the younger the person is, the higher the risk may be of them developing this injury in their quadriceps. 

The second risk factor is birth gender. According to a 2018 study, in those assigned female gender at birth (AFAB), biological factors such as a lack of blood flow response after running, can provoke a higher risk of them developing injuries in their legs.¹³  

The third risk factor is linked to structural properties of the ankle, since poor ankle dorsiflexion (less than 11.5%) can increase the risk of a person developing this injury.¹¹  

It is suspected that reducing the consumption of alcohol to less than 7 units per week for those assigned male gender at birth (AMAB) and less than 4 units per week in those AFAB, can aid in reducing the risk of becoming injured.¹¹ 

According to Medline Plus, Oxfloxacin, in comparison to other antibiotic drugs, in a statistical analysis, showed an increased risk for developing tendonitis.

Diagnosis 

Tests for quadriceps tendonitis include a clinical examination performed by a doctor and imaging techniques, notably ultrasounds, doppler and MRI scans, that can highlight the areas of swelling and the breakdown of collagen (which ordinarily gives the tendon durability and strength).^8,9 Doppler ultrasounds are an imaging technique used to show the increased blood flow in the tendon as a result of the swelling and ultrasounds may be utilized to localize the abnormalities in the tendon with additional ligament swelling.¹⁵ A usual presentation of this swelling will occur just on one leg whilst the other knee may feel weak depending on the cause of the strain.  

Treatment

Surgical

In many cases, unless the tendon has ruptured, the most common course of treatment is a holistic approach without any surgical interventions. Surgery is only needed if the non-surgical approach doesn’t work or if the tendon has ruptured.¹⁶ Repairing the ruptured tendon depends on the severity of the injury, but most common surgical techniques are patella drill holes, which 50% of patients were reported as undergoing in a study and simple sutures for 22.5% of the patients.¹⁷ 

Patella drill holes. The most frequently used technique, this is a procedure whereby drills are placed in varying locations on the patella in order to suture the tear and relieve the tension.¹⁸  

Simple sutures. In the simple suture technique, the knee is opened surgically and held in place with sutures (stitches) which then allows for the patella to be reconstructed in fragments with the aid of a reduction clamp.¹⁹ 

A surgeon will consult you using the relevant imaging technique on which type of surgery is recommended for your injury. 

Non-surgical 

Various non-surgical interventions can be implemented in order to strengthen the quadriceps tendon and these can include⁹

• Modifying activity to reduce strain on the knee e.g., less bending and jumping
• Stretching and warming up if doing any physical activity
• RICE (rest, ice, compress, elevate) method; applying ice two-three times a day for 20 minutes on the affected area  
• Using non steroidal inflammatory drugs for pain management 

Certain exercises can also be performed daily in order to strengthen and stretch the tendon in a form of rehabilitation. A physiotherapist may recommend both static and strengthening exercises. 

Static exercises. These contract certain muscle groups and may consist of plantar flexion and knee extensions.²⁰

Strengthening exercises. As the name suggests, these help to strengthen the muscles and for this particular injury these can be leg lifts and hamstring curls.²¹ Both the strengthening and static exercises should be performed daily. 

A physiotherapist or sports therapist can also recommend another intervention, which is kinesio taping. Kinesio tape which has properties of stretching up to 140% of its original length can help in reducing pain, swelling and muscle spasms.²² A specific type of kinesio taping called Y-taping can help for quadriceps tendonitis as it lessens the strain on the knee and allows for a greater muscle force.²³ One study established that kinesio taping, which can be readily bought online, can increase muscle strength, improve gait pattern and enhance functional outcome for those patients with a sports injury.²²

Recovery and outlook

For most patients, with the correct treatment and rehabilitation, the function of the quadriceps tendon will be regained and maintained with time. However, as a result of deterioration, chronic symptoms can occur and in some cases microtrauma to the tendon can lead to it becoming ruptured.⁹ Complications with treatment can arise becasue over-use of anti-inflammatory drugs can increase the risk of developing gastritis, and corticosteroids can rupture the tendon and weaken the fibers within the tendon. It is advisable to seek correct medical advice in order to reduce potential risk of complications.  

Summary

This article explored the painful knee condition known as quadriceps tendonitis. This can be caused by microtrauma arising from overuse of the joint when running, kneeling or climbing stairs. Additional risk factors include age, birth gender, structural properties of the ankle, alcohol consumption and the antibiotic ofloxacin. The condition is diagnosed by physical examination couple with MRI and ultrasound techniques. Treatments include several types of surgery, physiotherapy, exercises and anti-inflammatory drugs. For most patients, the outlook is generally good and recovery complete. In rare cases it can become a long term problem but this is relatively rare. If you experience any of the symptoms of quadriceps tendonitis, especially if you are in a risk group, you should consult a doctor.