What is Genu Valgum?
Valgum, more commonly referred to via medical terminology as "valgus" or "knock-knee" is a condition in which the knees angle inward toward each other, or the midline of the body, when the legs are fully straight. The opposite occurrence is genu varum, otherwise known as "bowleggedness".
Flexibility in the joints during childhood is completely normal, and is the reason why your children can sit cross-legged, or any other position you wonder how you were ever able to do.
Cases vary from slight to extreme, and are developed under a multitude of circumstances, including passively due to activity levels, hereditary, or retained as a result of a genetic disorder. Children who are "pigeon-toed" have an increased variability of retaining valgus into adulthood. According to , the average child has most prominent increase in valgus around age 4 at average 8 degrees, lessening each year with valgus averaging <6 degrees by age 11. Children in this study who's valgus was deemed within normal limits ranged from anywhere up to 12 degrees for ages 2-11.
What does that mean?
Valgum is extremely common, more common in fact than it's counterpart in genu varum. During youth, it's nothing to be extremely concerned about. Often, as children age and become engaged in more strenuous physical activities ( ex: running while playing soccer), the musculature in the lower extremities will naturally reduce the angle of varum. In other words - many a times, valgum is corrected on it's own.
What if it doesn't?
In most cases, physical therapy is an option to increase the strength on the lateral (outsides) aspect of the lower extremities, which will help to reduce the angle in a controlled environment. Teaching proper body mechanics through movement will increase the ability of the child to improve his/her valgum without the trained eye of a physical therapist, or the watchful eyes of their parents around.
If the angle is more severe, other options can be provided and discussed with an orthopedic specialist and a primary care physician to determine the best course of action.
Why should we correct it?
Genu valgum is not considered an emergency situation - nor should it be. It's a natural aspect of growing - simply something to be monitored. However, allowing valgum to stabilize and continue on into adulthood will create problems for the child later on in his/her lifetime. Multiple studies have shown that the presence of untreated valgum has an extremely high correlation with osteoarthritis of the knee and hip, misalignments of the pelvis and sacrum, which increase the risk of low back pain, leg length discrepancies, musculoskeletal issues, to name a few.
If that doesn't convince your young adult to improve their valgum condition, it may help to remind them that valgum is also correlated with an increase in non-contact ligamentous/soft tissue tears in the knee joint - those will end a season fairly quickly, and will increase their risk to tear a ligament simply performing a daily activity, such as jumping down off of a small ledge, or stepping off of a curb.
Knowledge is power!