Quadriceps tendinitis, also known as quadriceps tendinopathy or tendinosis, is a overload, tearing and inflammation of the tendon at the top of your knee cap. This tendon’s main purpose is linking the quadriceps muscles to the knee cap to straighten your knee. It’s used for used for so many daily activities every day like walking, getting up out of a chair. Your quadriceps tendon pain is in one of 3 stages of tendon damage. If you’re feeling tendon pain over the front of your knee you’d need an expert eye to have a look at it before it gets worse.
Onset of your quadriceps tendon pain can be sudden or it can develop gradually over time. The most common cause of quadriceps tendinitis is repetitive movement like climbing up and down many flights of stairs or doing a lot of squats or lunges, or even sports like volleyball, highjump and tennis.
What is the quadriceps tendon?
The muscle on the front of the thigh is called the quadriceps femoris and is actually a group of four muscles: Rectus Femoris, Vastus Lateralis, Vastus Medialis and Vastus Intermedius. Just above the knee the bottom part of these muscles form the quadriceps tendon which attaches to the top of the patella (knee cap).
A tendon is made up of parallel collagen fibres that connects muscle to bone. Collagen is a strong type of connective tissue that can withstand a lot of tension. Tendons need less energy and oxygen to function, so they can withstand load and tension for longer periods of time than muscles.
Tension in the quadriceps tendon keeps you from falling when going down stairs and allows you to sit down slowly instead of just dropping into a chair. The tendon maintains this tension to hold or control the movement of your knee. This means that bending or straightening your knee isn’t just all or nothing – you can bend your knee slightly and hold that position.
What does the quadriceps tendon do?
The quadriceps tendon acts like a pulley connecting the muscles on the front of the thigh to the knee cap. When the muscles contract it creates tension in the quadriceps tendon which causes the knee to extend (straighten). This happens every time you walk up a step or get up from a chair.
In normal everyday activities like standing the quadriceps tendon keeps our knee straight and straightens the knee with every step we take. During downhill running the tendon controls the amount that the knee bends to keep you from stumbling. Tendons absorbs kinetic energy to transfer it into the muscle or Tibia.
The quadriceps tendon handles significant loads during sporting activities. For example, to jump into the air a large amount of force is transferred through the quadriceps tendon to get you off the ground. When landing the quadriceps tendon works hard to keep the knee from bending all the way and it also acts like a shock absorber to soften the landing.
How does quadriceps tendinitis happen?
Healthy tendons are made up of densely packed, parallel collagen (connective tissue) fibres. This specific structure of tendons is what makes them so strong and resilient. The blood vessels that supply tendons also run parallel to these fibres, but the inner part of the tendon has a relatively poor blood supply.
Reactive tendinopathy
With overuse or overloading there will be thickening of the tendon to reduce stress on the tendon. There isn’t any inflammation during this phase and, if the load is reduced in time, there isn’t any permanent damage to the tendon. However, the thickening can cause some loss of flexibility. This process is called a reactive tendinopathy. A normal tendon responds to load and tension by stiffening, so the thickening is your body’s way of compensating for a lack of stiffness, trying to heal the tendon. Therefore your tendon works like a worn out spring that struggles recoil & expand.
This is usually caused by a sudden increase in activity, for example someone who doesn’t normally run doing a trail run. Falling directly on your knee will also case
Tendon disrepair
If a reactive tendinopathy is not managed properly – by decreasing the load on the tendon – the body will carry on this “healing” process. Unfortunately, this phase is different, because there is an increase in other cells in the tendon (not just collagen). These cells cause separation and disorganisation of the normal collagen in the tendon and small blood vessels develop in the inner part of the tendon, disrupting the tendon’s fibers from absorbing load. This is the tendon disrepair phase.
We normally see this condition if people carry on training through the pain for weeks of months. The tendon doesn’t have time to adapt in between the activities that cause the quadriceps tendinitis, like downhill running every day for weeks or repeated falls on your knee.
Degenerative tendinopathy
This phase is normally seen in older patients or athletes who kept on overloading the tendon for months or years. If you reach this phase, your condition cannot be reversed, because there are areas of “dead” tendon that cannot heal. These areas have lots of small blood vessels and very little collagen.
It’s not all bad news though, because there will still be areas of the tendon that can heal and this is what we as physiotherapists will focus on during treatment.
The main causes of Quadriceps Tendinitis
Quadriceps tendon pain could have a sudden onset or you could gradually develop pain over a period of time.
Sudden onset
A single incident, like after a sudden acceleration (a sprinter’s push off out of the blocks), jumping off a wall or falling directly on the knee can cause small tears in the tendon. This leads to quadriceps tendinitis because the tendon is loaded beyond its normal limits. Like a cable that snaps.
When you exercise – especially activities like downhill running, box jumps and kicking – the tendon must absorb the forces placed on it. However, tendons do not respond well to changes in activity. If you make big changes to your training, the loads on the quadriceps tendon will be higher than it’s used to . This causes inflammation and swelling of the quadriceps tendon which you will experience as pain at the front of your knee.
Gradual onset
The main cause of quadriceps tendinitis is overuse and repetitive overload. Tendons need time to recover after training, so insufficient recovery (“healing”) time causes a quadriceps tendinitis. This is why it’s important not to go back to training before your pain has settled. A tendon takes up to 48 hours to respond to load.
People who lead sedentary lives (if you sit for 6 hours a day, behind a desk or in traffic) have an increased risk of developing quadriceps tendinitis. The knee is in one position throughout the day, leading to tightness of the quadriceps muscles. When you do other activities, like climbing stairs or getting into your car, you need the full range of movement of the knee, but the tightness adds extra tension and load to the quadriceps tendon. Think of a big industrial cable under tension that cannot stand the loads placed on it – over time it starts to fray.
Running downhill your quadriceps muscle controls deceleration of your body, working as your “brakes”. Repetitive downhill running puts excessive force on the patella tendon and this is also referred to as runner’s knee.
Symptoms of Quadriceps tendinitis
How bad is it?
In the early stage of quadriceps tendinitis you will have pain above or below the patella after training or activity. The pain goes away with rest, but will return after your next training session. This phase is known as a reactive tendinopathy. If the tendon is overloaded there will be some thickening of the tendon to reduce stress on the quadriceps tendon. Normally tendons respond to loading by an increase in tendon stiffness.
Without treatment you will find that you have pain at the beginning of your training, but it disappears after your warm-up. The pain returns after training and settles again with rest. This stage is known as tendon disrepair. Your body tries to heal the small tears in the tendon when you rest, but you resume training before the tendon heals completely resulting in degeneration of the tendon.
If you do not get treatment in the previous stages of quadriceps tendinitis and continue overloading the tendon, your condition will progress to degenerative tendinopathy. There will be areas of cell death in this phase which can not heal. During this phase you will have pain and stiffness during and after activity. The pain does not settle with rest and you will not be able to exercise.
Where the tendon tears
The quadriceps tendon is very thick and combines the forces of the four quadriceps muscles – like four motors attached to one cable. If the force of the motors (muscles) is unevenly distributed to the cable, the cable will start shearing away from the motor. There are four points where the tendon can be affected.
- Above the knee cap, where the muscle attaches to the tendon, about two fingers above the knee cap (patella).
- Where the supra-patella tendon attaches to the top part of the patella (superior border).
- Below the patella (inferior border).
- At the attachment of the infra-patella tendon onto the tibia (shin bone), about four fingers below the knee cap.
Diagnosis
A Physiotherapist can diagnose quadriceps tendinitis by doing specific tests to load the tendon. We can assess the quadriceps muscle strength and tightness to find all the factors contributing to your pain. During our evaluation we also do passive joint tests and put pressure on other parts of the knee to pinpoint the exact problem.
We assess the whole leg to identify weakness, tightness or stiffness at your hip and ankle/foot which may contribute to your condition.
If we suspect damage to some of the other structures in the front of your knee we can refer you for further investigations. For example if we suspect the tendinitis has deteriorated to such an extent that there may be ligament damage or quadriceps muscle tears. In our experience, these are the patients who disregard the pain and just run through it for weeks or even months.
X-rays
X-rays only show bone, not tendons and ligaments. It may be used to rule out avulsion fractures where a piece of bone breaks away with a tendon rupture. With a normal quadriceps tendinitis a X-ray will be of little value.
Sonar
Diagnostic ultrasound shows the soft tissue and will be more useful than X-rays for quadriceps tendinitis. Any swelling, tendon thickening, involvement of the bursa or possible tears in the tendons will be visible.
MRI
MRI can only be ordered by a specialist. If your knee injury was traumatic (accident, tackle or landing awkwardly) an MRI will visualise the structures within the knee joint to rule out any other injuries to the menisci (Knee Meniscus Tear) and ligaments (Anterior Cruciate Ligament injury (ACL injury).
Why is my quadriceps tendinitis not going away?
When the tendon is overloaded with forces from the pull of the quadriceps muscles, inflammation causes the body to send cells to repair the micro tears in the tendon fibers. Almost like a cable that starts to fray, snapping small strands one at a time. If you keep on running through it, you will continue to tear away the cells that are trying to heal and close the tears. The more you run, jump, squat or lunge through the pain, the more damage you cause and the longer it will take to heal.
Your pain and tightness will be worse AFTER the activity rather than during. The reason for this is the inflammatory cells attempting to heal the tissue when you rest, causing an increase in pressure in and around the tendon. Tendons have poor blood supply compared to muscles and, therefore, take longer to heal and recover.
A big problem with Quadriceps tendon pain
A big problem that we see with quadriceps tendinitis is that patients delay treatment. In the early phases of the quadriceps tendinitis/tendinopathy, the pain settles down with rest, but the tendon degeneration and muscle tightness do not go away with rest. If you take a few days off until the pain in your knee is gone (usually 5 days) and then start running again, the pain will return. The cells that have started to heal will tear and the whole process needs to start from the beginning again.
By the time patients make an appointment to see a physiotherapist, they have had to stop training due to their quadriceps tendon pain. This means that their tendinitis has progressed the stage of tendinopathy where there is degeneration of the tendon. As soon as there is degeneration we need to drastically change your activity to limit further damage to the tendon. This means that you will have to take time off from whatever is causing your pain. If you make an appointment with us before you reach this stage, it might only be necessary to decrease the load of your activity without stopping completely.
Another problem we see is that patients do not want to rest or change their activity. Tendinitis is an overuse injury, so the tendon needs active rest to heal, so you must modify your activity. If you carry on with your normal activities and training – which caused the problem in the first place – the tendon will not heal and the condition will just get worse until you’re forced to stop.
Physiotherapy treatment for quadriceps tendinitis
The most important part of physiotherapy treatment for quadriceps tendinitis is modifying your activities and training. The first thing to do with an overuse injury is to change what is causing the problem in other words manage the load on the tendon.
When you still have a lot of pain we will see you twice a week for treatment. This treatment will focus on pain management by means of electrotherapy, strapping and isometric exercises. Muscle tightness and trigger points will be addressed by acupuncture or dry needling, massage and stretches. Ultrasound, laser, strapping and taping will be used during the course of treatment to support the healing process.
As soon as your pain is under control we start to load the tendon with exercises specific to the phase of healing you are in. We will gradually progress your rehabilitation exercises to increase the tendon’s ability to handle these loads. Tendons take longer to heal than muscles, so rehabilitation can take 3 to 6 months.
Progression of Loading
- You will start with open-chain exercises, in other words exercises where you don’t put weight on your foot. These exercises put very little strain on the tendon and are different variations of knee extension (straightening). Starting with exercises where there is very little to no movement (isometrics) and gradually increasing the range of movement of the exercise.
- Next you will start with partial weight-bearing exercises like wall squats progressing to normal squats. The other leg takes some of the weight during these exercises, so all of the load isn’t on your injured knee.
- After partial weight-bearing we start conditioning your tendon to tolerate full weight-bearing like lunges progressing to single leg squats and pistol squats. These exercises are only performed with body weight until your tendon can do these movements without pain.
- Now you’ll progress to loaded exercises like knee extensions against elastic resistance and weighted squats. Initially with easy resistance, but before we move on from loaded exercises you will do heavy, slow resistance exercises. This is important to change the tendon’s capacity to withstand loading which leads to long-term improvement in the your quadriceps tendon pain.
- The next part of rehabilitation involves the stretch-shortening-cycle of the tendon. This is when the tendon acts like a spring for jumping activities, going from a lengthened position (stretch) to a shortened position (contraction) in a short period of time. A tendon should be able to withstand this kind of load without flare-ups or pain. Exercises will include skipping, box jumps and single leg hops.
- Running drills will be some of the last exercises before you finish rehabilitation. These drills will include acceleration and deceleration, rapid direction changes and a combination of running and jumping.
Phases of rehabilitation
1st Phase: Protection & initial Healing
P
Protect.
Pain is the body’s way of protecting an injured area by letting you know that something is wrong. If you carry on with painful activities the healing process will have to restart over and over again. If you start to limp due to pain, it might be better to use crutches for a few days to decrease the load and protect the tendon.
R
Rest.
Rest from activities that are worsening your quadriceps tendon pain.
Reduce the weight taken on the injured leg. Use crutches to take the load off your quadriceps tendon.
As soon as there’s no pain, don’t test it. Give it time to heal.
I
Ice.
Ice cubes wrapped in a towel or an ice pack tied around the front of your knee can reduce pain. You can apply an ice pack for 20 minutes every two hours. Always keep a towel between the ice and your skin (to prevent freeze burn).
E
Elevate.
If your knee is swollen, you can lie Lying on your back with your foot on a chair (your knee must be higher than your heart to allow gravity to assist in draining the pooled blood in your leg.) Raise your calf for 15 minute intervals during the day.
2nd Phase: Establish pain free range of movement
During your examination and test, it’ll become clear what you’ll be able to do, and what you should avoid. We identify factors that contribute to your quadriceps tendon pain, which are specific to your case. There is a pain free range of movement that you’re safe to move in, and our exercises will be targeted between these boundaries i.e Pain free range is from 0 – 30 degrees, 30+ degrees is painful. On completion of this phase you should be able to perform movements within limits.
Bending your knee will be painful during this phase, because the painful tendon will not be able to tolerate the compression. Straightening your knee with added load, even just body weight, will also be painful. Therefore, we will give you exercises with little or no movement in the middle of your knee’s normal range during this phase of rehabilitation.
As your rehabilitation progresses we aim to gain a larger pain free range of movement while your painful range becomes less intense.
3nd Phase: Tissue healing
The three phases of quadriceps tendinopathy (reactive tendinopathy, tendon dysrepair and degenerative tendinopathy) are not like muscle phases of healing that only go in one direction. For instance, if your reactive tendinopathy is overloaded it could get worse and go into the tendon dysrepair stage. Therefore it is crucial that we monitor the progress of your pathology.
On a cellular level we’re able to accelerate tissue healing using dry needling, laser, ultrasound and electrotherapy.
4nd Phase: Tissue Stress & ability to heal
During each session we will re-evaluate if you are achieving the necessary targets for your quadriceps tendon to be able to handle tensile, elastic and compression forces. We use isometric muscle contractions. These are muscle contractions without movement to keep the surrounding muscles active without placing excessive load on your quadriceps tendon.
5nd Phase: Muscle Strength & Full Range of Movement
Tightness of your quadriceps muscles will put extra tension and load on the quadriceps tendon and limit the full range of movement of your knee. We use massage, dry needling and neurodynamic mobilizations to treat the muscle tightness and regain full range of movement. The quadriceps tendon pain takes a backseat at this stage.
Strength training is an important part of tendon rehabilitation, because we want to retrain the tendon to handle the load when the muscles generate force. If the muscles are weak the tendon cannot adapt to increasing load.
Performing exercises slowly against heavy resistance has been shown to lead to changes in the muscles’ and tendon’s capacity to manage loads. During this phase these exercises will be done in the middle of the available range of movement to prevent compression of the tendon. As the tendon needs time to adapt and recover, you will only do these exercises 2-3 times per week.
As your quadriceps tendon heals and pain improves the range of movement of your exercises will also change. We will start moving into ranges that used to be painful and eventually you will be able to go through the full range of movement of your knee without pain.
6rd Phase: Eccentric Muscle Strength
It’s common to feel some pain when we start loading the quadriceps tendon – this is due to breaking down abnormal fibrous tissue adhesion in the tendon. Tightness in the quadriceps femoris will also affect the normal function of the tendon.
A muscle contraction works in two directions: One where the quadriceps muscle is contracted and it shortens like a getting up from a chair (concentric), and controlling the descent sitting down (eccentric). This loads your quadriceps tendon while it is lengthening and this lengthening compresses the tendon. These types of exercises are vital at conditioning the tendon to absorb a force, because the tendon must be able to tolerate load in a position of compression.
On completion of this phase you should be able to do a slow, deep squat without pain.
7th Phase: Testing for return to activity
In this phase we will start with a gradual build up into your previous intensity of normal activities and training to determine if your quadriceps tendon can withstand repetitive loading without flare-ups. Our physiotherapist guides you to re-engage in safe increments with adequate rest to give the tendon time to heal and adjust your program where necessary.
8th Phase: High Speed, Power, Proprioception
Your quadriceps tendon must be tested under high load and speed to ensure that it can keep up with the demands of your body. During this phase our physiotherapist will guide you to return to normal activities, this includes challenging your quadriceps tendon past its ‘normal’ boundaries to determine how it reacts to different forces. Ultimately we prepare you to return to participating in your sport.
Whatever must be done – we’ll get you there. Jumps, Landing, Sprints, and much more.
9th Phase: Sport Specific Training
This is the final stage of rehabilitation that can last anything from 2-4 weeks. Your physiotherapist will still continue with myofascial release, trigger point release and electrotherapy modalities where needed, but functional rehabilitation is most important during this phase.
Our physiotherapist will tailor specific exercises that will help strengthen the muscles and condition your quadriceps tendon specifically for your sport. A successful outcome is when you have gained knowledge throughout the rehabilitation program and can participate at full power and speed without any lingering pain, not to mention the benefits of minimizing your chance of future injury.
Healing time
Your Quadriceps tendon has poor blood supply compared to muscles, hence their white appearance on anatomy charts. Depending on the stage of your tendinitis, healing time could be from 6 weeks to 3 months. Initially physiotherapy treatments will be once to twice a week (depending on your pain), but as your quadriceps tendon pain improves we will see you once a week and later once every second week to progress your rehabilitation home program.
Other medical treatments
- Medication – Your GP may prescribe analgesics or anti inflammatories to decrease pain.
- Cortisone injections – A cortisone injection will clear all inflammation in the area, which decreases your quadriceps tendon pain considerably. However, it causes changes in the integrity of the tendon which can lead to tears or ruptures in the future.
- Brace – A knee ranger can be used to limit movement while your quadriceps tendon heals.
Surgery for quadriceps tendinitis
If your quadriceps tendon pain do not respond to 3 months of conservative treatment, surgery may be an option. Another reason for surgery would be if there is a complete rupture of the tendon off its anchor sites.
Surgery is performed via arthroscopy (keyhole surgery) to remove the damaged tissue and/or repair the quadriceps tendon. After surgery rehabilitation is crucial to restore the tendon’s normal function and to strengthen all the muscle around the knee. Without rehabilitation there is a very high risk of re-injury to the quadriceps tendon.
Also known as
- Quadriceps tendonitis
- Runner’s knee
- Quadriceps tendinopathy
- Pain over the knee cap
- Quadriceps tendonosis
What else could it be?
- Patella dislocation – The pain will be more on the outer side of the patella and you will not be able to straighten the knee at all. You will also have pronounced swelling of the whole knee.
- Patellar bursitis – Pain will be worse during activity and specifically when kneeling on the ground. Pressure on the are will also make your pain worse.
- Quadriceps muscle strain (tear) – Your pain will be over the front of the thigh rather than the knee.
- Knee Joint Osteoarthritis – The pain will be deeper and you will have significant knee stiffness in the mornings or after sitting still for a period of time.
