What is Bow Leg Deformity?
Bowlegs is also known as ‘genu varum’. Bowlegs is the deformity in which both the legs appear as bow-shaped structure.
It is a deformity in which the tibia turns inwards instead of lying parallel with the femur. Or you can say the bone of the lower leg points medially towards the midline. Normally it goes away without treatment, sometimes treatment options like medication, braces, casts are required and surgery is required in severe cases.
You can remember it by making a mnemonic like when you pronounce the word varum. There comes the word ‘rum’ which means if your place the rum bottle in between the legs, it will keep your knee apart.
Normally babies are born with bow legs. Let me explain to you the term baby and the reason why babies are born with bow legs.
Bow Leg in Babies –
The word baby is used for any child whose age lies between birth to 4 years old. It is then further classified into newborns, infants, and toddlers. The newborn will be called baby from birth up to 2 months, and an infant will be referred to as a baby from 2 months to 1 year. And a toddler will also be called a baby from 1 year to 4 years.
Babies are born with bow legs because during pregnancy or when they are in the uterus(womb). They are in a folded position. But, when they reach up to 2 years of age bow legs will be no more, because as the baby starts to walk his bow legs will begin to straighten.
And after 2 years of age the alignment of the knee changes to valgus (knock knees) at around 3 years of age. And after that knock knees will nearly correct by the age of 6 or 7 years and the normal adult alignment is usually reached at around 8 to 10 years of age.
In case if the bow legs not get corrected by the age of 2 or 3 years then bow legs can be due to some underlying cause such as rickets, infections, injuries, or due to Blount’s disease. Then treatment options should be considered like braces, casts. medication or surgery will be done for the correction of bow legs.
Bow Legs or Genu varum Causes –
Causes of bow legs in babies-
Sometimes in babies, rickets can cause bow legs, In rickets, there is a drop in levels of vitamin D. There is an unusual change in the growth plate that causes soft bones.
Physiologic genu varum
Normally at birth some amount of genu varum(bowing) is present, and it usually disappears during the 18 or 24 months of life. This type of bowing is referred to as physiologic genu varum, Sometimes even after 2 years of age this bowing does not disappears. And it becomes very hard to differentiate between the physiologic genu varum and infantile Blount’s disease.
The major difference between physiologic genu varum and Blount’s disease is that in Blount’s disease the upper growth plate of the tibia is got affected.
It is a condition that happens in young children or adolescents. This disease affects the upper growth plate of the tibia, Generally, Blount’s disease is of two types (early-onset and late-onset) depending upon if symptoms
- Infantile Blount’s disease – Symptoms begin before 4 years of age generally around 18 to 24 months. However, it becomes impossible to differentiate between normal developmental bowing(physiologic genu varum) and infantile Blount’s disease. When things go out of hand or bowing got worsen then it can be seen on X rays.
- Adolescents Blount’s disease – Symptoms begin after 10 years of age.
Infections can also affect the growth plate of the bones that will lead to bow legs. ex osteomyelitis.
Causes of Bow Legs in adults & adolescents –
Here are the names of some of the conditions that can lead to genu varum in adults & adolescents.
Adolescents Blount’s disease
Generally, In Adolescents Blount’s disease, symptoms begin after 10 years of age. And until 10 years of age, this condition remains normal in babies.
Osteoarthritis of the knee
In osteoarthritis, the destruction of the articular cartilage takes place between the knee joint. So it can bend your knee outwards and lead to bow legs. However, osteoarthritis can also be a cause of it or it can be a result of bow legs.
High Arch Feet
If your feet are high arch means they are abnormally raised. It can bring your foot as well as your lower leg (tibia) out of the side more as compared to a person’s normal lower leg. So there will an appearance of bow legs.
The work of the adductors muscle is to bring your legs closer to your midline. If there is a weakness in adductors muscles it will bow your legs out away from the midline.
Genu varum Symptoms –
Children will not feel any type of pain or discomfort but the amount of bowing will be visible when a child walks or stands. However proper consultation should be taken from the doctors if symptoms like these appear after the age of 3.
- When the child is not able to touch both his knees but his feet and ankles are touching.
- Bowing getting worsen along with symmetrical bowing in both the legs
- Hip range of motion getting reduced
Adults and Adolescents
However, in adults and adolescents bow legs do not cause pain. But persistent bowing can lead to pain and discomfort in the ankles, knees, hips, and in the future. Because the abnormal symmetry places abnormal stress on the knee’s joints.
Bow Legs Diagnosis –
Intercondylar distance – Your doctor will initially check your child’s Intercondylar distance. It is measured by holding your child’s ankle together and by measuring the distance between the knees. It will give u an indication for the bow legs if your Intercondylar distance is more than 6 cm.
Clinical thigh leg angle – Your doctor will measure your Clinical thigh leg angle ie the angle between your thigh and the leg. If it is more than 20 degrees.
Then your doctor will order an X-ray in the following cases –
- Still persistence of bow legs after 2 years of age.
- When there is an aggravation of bow legs after the age of 1 year.
- Your clinical thigh leg angle is more than 20 degrees.
- If your Intercondylar distance is more than 6 cm.
Infantile Blount’s disease – Infantile tibia vara is one of the most common findings of genu varum because in this the upper growth plate of the tibia got affected.
In general, it gets misdiagnosed with normal developmental bowing and in case if it left untreated. It will lead to mild laxity of Lateral collateral ligament in the future when the child gets older.
Measurement – Your doctor will also draw a straight line from the anterior superior iliac spine passing through the center of the patella to the medial malleolus. Normally all the structures lie in the same line, but in the bow legs, medial malleolus lies medially to this line.
This line can be drawn on the body but for the better result, it should be drawn on full length lower limb x-ray.
Bow Legs Treatment
HOW TO CORRECT/CURE BOW LEGS –
Here the most important question arises regarding bow legs is that how we can correct/ cure bow legs. Generally, there are two types of treatment for correcting bow legs Surgical and Nonsurgical.
Age also plays an important role in the treatment like the weather you are treating babies or adults.
Bow Legs Correction in babies –
Correction of bow legs in babies is done according to the etiology. At first, the doctor will identify the cause then after identifying the cause treatment is done.
Rickets – In case if your child has rickets, your doctor will prescribe you vitamin D and calcium tablets. As well as he will also suggest you to add vitamin d and calcium in your diet.
Sometimes when the conservative treatment got failed then they require surgical interventions. Generally, guided growth surgery is performed.
Physiologic genu varum – It does not require any treatment, Your doctor will consider it normal and will call your child for a regular check-up every in 3 months until the bowing has resolved.
It happens very rarely that after 2 years of age the physiological genu varum does not get disappear. And if the cause is not rickets or infantile Blount’s disease. Then in between 4 to 17 years of age when the physiological bowing gets severe, Guided growth surgery is performed.
Infantile Blount’s disease – Generally, it gets misdiagnosed but if you get diagnosed early, your doctor will give you brace. It will slow down your disease progression,
Despite being conservatively managing the disease with bracing, and if it gets fails tibial osteotomy surgery is performed by the age of 4 years. As it will permanently stop the damaging of the shin bone(tibia).
Bow Legs Correction in Adults & Adolescents
In general, many people think that the first line of treatment for the correction of bow legs in adults & adolescents is surgery. But it is not true you can correct bow legs in adults by doing appropriate exercises, change in diet plan as well and in lifestyle.
Adolescents Blount’s disease – In this disease symptoms begins after 10 years of age, and until 10 years it remains normal in babies. You can correct it by doing exercises, diet, and lifestyle modification.
But if conservative treatment fails, then surgery is the last option.
Osteoarthritis of knees & high arch feet – If bowing is due to osteoarthritis in the knees or due to high arch feet. Then at first, you should consult your doctor or physical therapist and treat these conditions that are causing bow legs.
Your physical therapist will guide you with the best therapeutic exercises to get rid of these conditions.
Adductors Muscles – Sometimes bowing is caused by muscle imbalances and muscle weakness in adults. Generally, adductors muscles are involved.
So consult your physical therapist he will guide the best set of exercises for balancing or strengthening your adductors muscles.