Also referred to as “knock knees,” knee valgus is a common misalignment characterised by the inward bending of the knees.
This condition is most frequently seen in young children, but in some cases, this potentially painful condition can persist into adulthood.
There are several other known causes of knee valgus. Some are structural deformities, such as rheumatoid arthritis or a deformity of the knee joint, femur, or tibia.
Knee valgus caused by these deformities is not preventable and cannot be reversed, but there are several treatment options available that can help ease the discomfort associated with this condition.
For the purposes of this article, our main focus is on another common cause of knee valgus that can be prevented and corrected: muscle imbalance due to poor posture.
In this post, you’ll learn what knee valgus is, what causes it, and how knee valgus caused by poor posture can be fixed.
What is Knee Valgus?
Knee valgus occurs when the femur rotates inward, whether due to structural deformity or weakness in the muscles and ligaments that support the knee.
When it occurs both knees point towards one another in a standing position, rather than being pointed forward.
Typically, someone with knee valgus will have their femurs pointed inwards with their hips being in constant internal rotation. These two factors work together to rotate the knees inwards.
Furthermore, flat feet or collapsed arches normally accompanies knee valgus. Some people may also have tibia (shins) external rotation to compensate for the knock knees.
Symptoms of Knee Valgus
The most obvious symptom of knee valgus is a knock-kneed appearance of the legs. Most adults with mild cases of valgus will not experience any pain or discomfort.
A simple way to test for a valgus misalignment is to stand with your legs together and note whether your knees and ankles are touching.
If your knees are touching but there is a gap of at least 2 inches between your ankles, you most likely have knee valgus.
If left untreated, however, valgus may progress and cause symptoms such as:
- An altered gait
- Foot, ankle, and hip pain
- Difficulty balancing
- Reduced range of motion
- Knee pain
- Low back pain
There aren’t too many side-effects of having a mild case of knee valgus, however, if you do have knee valgus it is something you will want to correct it rather than ignore.
Furthermore, correcting knee valgus can improve your movement, and as we will see later, your overall posture.
Possible Causes of Knee Valgus
In this section, we’ll look at the possible causes of Knee Valgus.
The causes of knee valgus are plentiful. Some of the cases of knee valgus are caused by bone deformities and complications such as Osteoarthritis, Rickets and Scurvy.
Genetics has also been known to play a part with some people developing it early and some people developing it later in life.
Knee valgus is common in young children, with more than 20 per cent of kids under the age of 3 having a gap of at least 0.4 inches between their ankles. In most cases, however, the condition corrects itself as the body matures. Studies show that by the age of 7, only 1 per cent of children have a gap.
In some cases, knee valgus may continue into adolescence or develop in adulthood. These cases are rare and usually the result of an underlying illness or condition, such as Blount’s disease.
One other common cause of knee valgus is poor posture. This is what we’ll explore in more detail in the next section.
How Does Poor Posture Cause Knee Valgus?
In order to understand how poor posture contributes to knee valgus, it’s important to consider how the muscles of the hips and legs work together to ensure proper alignment of the knee.
The knee joint is supported by a network of muscles that not only allow for a full range of motion, but also stabilize the knee.
These muscles include the hip abductors, the external rotators, the quadriceps, and the hamstrings.
When the knee is properly aligned, your weight is distributed evenly along a load-bearing axis that runs down through the hip, knee, and ankle.
When the muscles that stabilize the knee become weak, whether due to trauma or overuse, a misalignment of the knee can occur.
In the case of knee valgus, weak hip external rotates, hip abductors, and pelvic muscles cause the femur to rotate inward, resulting in a knock-kneed appearance.
It is important to keep in mind that some degree of varus (“bow legs”) or valgus (“knock knees”) is normal and won’t produce any noticeable symptoms or loss of movement.
The Muscle Imbalances and Postural Dysfunctions that can lead to Knee Valgus
Much of the time knee valgus develops as a result of dysfunction in certain parts of the body:
- Tight Adductors – Adductors are the muscles which run down the inner thigh/groin area. If these are too tight, the tightness will pull the thighs inwards and the hip into internal rotation. The result of this is the knock-knee effect.
- Weak Abductors – The abductors are the muscles that help pull the legs away from the midline of the body. The sufferer of knee valgus is likely to have weak abductors, whilst the adductors are too overactive. Since the abductors are too weak, the inward pull is greater than the outward pull. The lack of balance between the two muscle groups results in the knees pointing inwards.
- Flat Feet – Flat feet or collapsed arches will cause the knee to become misaligned and pointed inwards.
- Naturally Wide Hips – This isn’t necessarily a cause, but people with wider hips are at a higher risk of developing knee valgus over time. Wider hips are more prone to internally rotating resulting in the knees caving inwards. This is one reason why women seem to suffer from knee valgus more than men.
- Anterior Pelvic Tilt – If the front of your pelvis tends to be tilted downwards in an anterior pelvic tilt, this can cause the hips to internally rotate forcing the knees to point inwards.
Finding the root cause of knee valgus is not a simple job. Since the knee is in the middle of the hip joint and the ankle, the problem can originate from either end.
For example, most people with knee valgus have flat feet. Was it the flat feet that caused the knee valgus, or was it the internally rotated hip that caused the knee to buckle inwards which then caused the flat feet?
This complication in addressing the root cause can make it harder to find the best way to fix knee valgus.
The good news is that if knee valgus that occurs due to poor posture can be corrected if it is identified early.
In the following section, we’ll take a look at some of the treatment options that are available for correcting knee valgus.
How to Correct Knee Valgus
For severe cases of knee valgus, more aggressive treatment may be required to ease pain and prevent the condition from worsening.
Depending on the underlying cause of knee valgus, a doctor may recommend:
- Medication – In some cases, knee valgus may be caused by an underlying illness like rickets (calcium and vitamin D deficiency). In these cases, treating the underlying condition with medication may help correct the misalignment of the knee. Medications may also be used in the management of pain while following an individualized exercise program to correct knock knees.
- Surgery – Surgery to correct knee valgus may involve guided growth, in which a plate is inserted into the knee to correct the alignment of the joint, or osteotomy, in which the femur is realigned in order to correct the angle of the load-bearing axis. In rare cases, a total knee replacement will be recommended.
In cases where knee valgus is not caused by a structural deformity or underlying illness, most doctors and physiotherapists will recommend some simple exercises to strengthen weak hip external rotators and hip abductors.
Stretching exercises may also be recommended to restore flexibility to the hips and lengthen the tight muscles.
These stretches and exercises are aimed toward realigning the knee in order to correct the load-bearing axis and reduce pressure on the knee, hip, and ankle joints.
We’ll take a closer look at specific exercises you can try in the next section.
Corrective Exercises to Fix Knee Valgus
In this section, we’ll cover some exercises and postural issues to address and consider when fixing your knee valgus.
Before attempting any type of correction at home, however, it’s a good idea to consult with your doctor to rule out any underlying conditions that could be causing your knee valgus.
1. Stretch & Release Tight Adductors
The adductors are a group of muscles that run the length of the inner thigh and groin area, if these muscles are too tight, they will cause the knees to buckle inwards.
As a result, someone with knee valgus will find it helpful to begin a program of frequently releasing and stretching these muscles.
Another less commonly explored treatment option for knee valgus is trigger point therapy. Also known as myofascial release, trigger point therapy focuses on releasing muscle knots deep in the body’s soft tissues in order to increase circulation to the affected area, reduce inflammation, eliminate pain, and restore symmetry to the muscles, ligaments and joints that stabilize the knee.
Myofascial release is a type of manual therapy that is usually performed by a massage therapist, but there are many tools available on the market that can help you achieve myofascial release at home – such as foam rollers.
To lengthen the adductors you will want to perform both myofascial release and stretching on them.
To release the adductors, you will need a large myofascial release tool to perform myofascial release. A standard massage ball is likely to be too small unless you can raise it up somehow. You can use a foam roller like in the video above, however, we found the 5-inch Triggerpoint ball (which is larger than a regular ball) to be the most helpful in this situation.
Given the chronic tightness in the adductors, you may have to perform myofascial release several times.
The next important step after releasing the adductors is to regularly start stretching them.
There are several ways to stretch the adductors, however, we have found the standing adductor stretch to be the best as you can always shift about until you feel the desired stretch.
Start a regular adductor stretching routine and you should find it helpful in restoring balance to your thigh area.
2. Strengthen Weak Abductors
This is not the same muscle group as we just talked about.
These are the Abductors, not the Adductors. The role of the abductor’s muscles is to pull your leg out to the side and away from the midline of the body.
When these muscles are too weak, they allow the tight adductors to pull the leg inwards. By beginning to strengthen them, we can create a better balance on both sides of the legs.
The abductors are primarily formed of the tensor fascia lata (TFL), the glute medius and the glute maximus.
You will want to ensure that these muscles are firing and strong, especially the gluteus medius which is commonly weak in many people.
To read more on how to strengthen your glute medius see this article on weak glute medius.
In addition to those articles, here are some exercises you can start doing to help strengthen the abductors.
Side-Lying Leg Raises
This exercise is simple to perform. Lie on your side and abduct the leg away from your body and then back down. Repeat this motion doing 30 reps on each leg. Make sure to keep the toes pointed down to work all abductor muscles
Side Planks with Leg Raise
Side planks where the top leg is raised is a great strengthening exercise. If you have weak abductors this exercise will be quite tough, in which case it may be better to start off with a modified version shown below.
Someone with knee valgus will want to focus their attention on performing squats with proper form. If you place bands around your knees this will force you to push your knees against the bands activating the abductors.
If none of those abduction exercises appeals to you how about 19 more? Watch the video above and choose the ones that you like.
For further exercises, you may also like to see our page on the external rotators of the hip.
3. Fix Flat Feet or Collapsed Arches
Since knee valgus is often accompanied by flattened arches, a physician may recommend wearing orthotics or insoles for flat feet to correct your gait and ease pressure on the knee, hip and ankle joints.
You may also want to look into the idea of fixing your flat feet through exercises that help strengthen the arch of your feet.
For more information on how to do this see our article on how to fix flat feet.
4. Check for an Anterior Pelvic Tilt
The presence of an anterior pelvic tilt can contribute to knee valgus.
An anterior pelvic tilt is where the front of your pelvis is tilted downwards and the back tilted upwards. A pelvis which is held in such a position may cause the femurs to internally rotate which forces the knees to turn inwards causing the knock knees.
To give yourself the best chance of fixing your knee valgus it’s a good idea to check if you have an anterior pelvic tilt, and look to do corrective exercises to stabilise your pelvis.
See our anterior pelvic tilt page on symptoms, how to test for it and how to fix it.
How to Prevent Knee Valgus in the Future
Knee valgus that is caused by a structural deformity usually cannot be prevented.
If your knee valgus is due to practising poor posture, however, there are a few simple lifestyle changes you can make in order to prevent the condition from worsening.
- Maintain a healthy weight. Numerous studies have linked obesity with severe knee valgus [1,2]. Excess weight places extra pressure on the legs and knees, which can exacerbate knock knees.
- Avoid hyperextending your knees. Focus on maintaining some flexibility in the knees when standing and walking. Hyperextension of the knee can cause injury to the medial collateral ligament (MCL), which helps prevent the knee from buckling inward, and the anterior crucial ligament (ACL), which provides rotational stability to the knee joint.
- Practice good posture when sitting. When sitting in a chair, your knees should be bent at a 90-degree angle with your feet flat on the floor. Avoid sitting with your knees together and your ankles apart.
- Practice good form. If you have knee valgus and are already working out, you will need to become more aware of your form and particularly where your knees are, compared to where they should be. For example, if you are in a squat don’t let your knees cave in but keep them tracked over the toes. If you are in a single leg lunge keep your knee stacked above the ankle and do not allow them to collapse inwards. Doing simple things such as these will start to work the muscles that aren’t firing and over time you may start to notice that your knee alignment may start to improve.
Fixing Knee Valgus is Not Simple but Form Counts
The exercises here are a great place to start and something you can do in isolation. But as you go about your day keep in mind what you are doing with your knees.
Look to correct the muscle imbalances from the hip all the way down to your knees because knee valgus isn’t just about the knees.
If caught in its early stages, mild cases of knee valgus can be prevented from worsening and contributing to the development of more serious conditions like arthritis of the knee and osteoarthritis.
Remember, the advice provided in this article is not meant to replace the advice of a medical professional.
If your knee valgus is accompanied by swelling or buckling of the knee, you may have an underlying condition that is causing your knock knees. Before attempting to correct knock knees, consult with your doctor about possible causes and treatment options for your knee valgus.