Main article: Knee inversion and knee valgus, which manifest clinically as “O” and “X” shaped legs, are among the most common causes of orthopedic visits in children. Do all inversions and valgus require treatment? What can be done to help the child recover? These are the questions that parents are very concerned about, and they are also in this issue of the “Top 10 Most Common Health Problems in Children Family Guide”.
Q: What do you mean by inversion or valgus?
A: Knee inversion and knee valgus are outward and inward angular deformities of the knee, which are more common in pediatric lower limb deformities. The inversion of the knee is most often seen in the upper tibia and fibula, and the ectropion of the knee is most often seen in the lower femur.
Q: What are the causes of internal and external knee valgus?
A: There are two types of causes: physiological and pathological.
Physiological knee valgus is a normal physiological process during the developmental stage of a child. At toddler age, most young children have a slight inversion, with an angle of 0 degrees-15 degrees. At 1-2 years of age, this inversion changes to an outward angle. Generally, children within 2 years of age do not have straight legs, and if they are not particularly severe, they mostly have physiological inversion of the knee.
Within 2 years of age, there is a normal range of normal tibio-femoral angles for physical development, and the normal tibio-femoral angle for children at this time varies widely, ranging from 2 degrees of inversion to 20 degrees of valgus. after age 7, the normal range of valgus is 0 degrees-12 degrees.
Beyond 2 years of age, the physiologic knee valgus will correct naturally as the pediatric leg muscles develop and balance improves significantly.
There are many causes of pathological knee ectropion, such as rickets, trauma, inflammation, congenital skeletal growth disorders, skeletal achondroplasia, skeletal dysplasia, type IV mucopolysaccharidosis or cartilage ectodermal dysplasia, tumors, poliomyelitis and cerebral palsy.
Q: What kind of internal and external knee rolls need intervention?
A: For children over 3 years old, whether inversion or ectropion, with an angle of more than 20 degrees, both inner ankles more than 3 cm, or excessive distance between the knee joints of both legs, it should be considered as a possible pathological leg deformity that requires medical intervention.
Q: How is it diagnosed?
A: Knee valgus is common in children aged 3-5 years, when the tibio-femoral angle is at its maximum valgus position and is more likely to be noticed by parents.
Diagnosis can be made using imaging. In the standing position, anteroposterior x-rays of both lower extremities (hip, knee and ankle) are taken to assess the internal and external knee valgus, including the anatomic and mechanical axes.
In patients with skeletal dysplasia, if the cartilaginous epiphysis is clearly not ossified, an MRI may be required in order to assess joint alignment.
It is important to remind that if the inner ankle of both feet does not exceed 3 cm, an x-ray is usually not necessary and is physiological. There is also no need to wear braces or orthopedic shoes, it will recover on its own, so parents should rest assured.
Q：How to treat?
A: Physiological inversion and developmental valgus of the knee in children between 2 and 6 years old do not require special treatment, and 95% of them will correct on their own.
Children under 8 years old have room to grow and develop their knees. If the knee inversion is more severe, i.e., the ankle spacing and knee spacing is more than 5 cm, braces and orthopedic shoes should be worn with the aim of protecting the knee joint from ligament instability. The above orthoses can be applied for 1-2 years. Mild cases of internal and external knee valgus (knee and ankle spacing less than 125px) require only nighttime braces, and above moderate cases (knee and ankle spacing between 5-250px) require additional braces for daytime use. If the treatment is not effective after orthopedic treatment, surgery should be considered.
Surgery should be considered for inversion of the knee where the distance between the knees exceeds 10 cm and ectropion of the knee where the distance between the two inner ankles exceeds 10 cm. The age of surgery should be postponed until after 12 years of age as much as possible to reduce the recurrence rate.
Those with severe congenital familial tibial entropion and significant abnormalities in lower extremity force line alignment by adolescence should be treated surgically. The tibiofibular osteotomy is performed at the angle of formation, and the torsional deformity of the tibia can be corrected at the same time during surgery. If the child is of appropriate bone age, asymmetric epiphyseal block of the proximal lateral part of the tibia plus fibular osteotomy is feasible, which can correct the deformity.
Children with rickets should be treated surgically when the self-conscious symptoms disappear, blood calcium, phosphorus and alkaline phosphatase are checked and it is determined that rickets has become quiescent, and surgery is feasible for those who are older, have hard bones and have knee spacing of more than 250px.
Q：Will hip dysplasia lead to O-leg?
A: No.
For hip dysplasia, a brace can be worn for hip joint correction. Generally, children within 1 year of age wear them for 3 months, and those over 1 year of age wear them for 12 months.
Q: When should I wear corrective shoes?
A: Those who are over 3 years old but the angle of deformity is not obvious can wear custom-made orthopedic shoes to stimulate foot development and help correct the deformity. It should be reminded that it is important to ensure that the shoes are worn every day, both during the day and at night.