Bowleg & knock knee is the opposite deformity in the lower limb. In bow leg, the leg is bowed outward from knee and below so that distance between knees is high, but ankle touches together, but in knock knee, both side of the knee on medial surface touches together, but the distance between ankles remain high. Both of these deformities can be physiological (a normal, natural occurrence) but also be because of some pathological ailment also. Normally at the time of birth, most of the leg in a newborn is bowed outward and slowly it corrects spontaneously around the age 18 months to 2 years than in natural course legs go in and develop knock knee and became more prominent at the age 3 years. Afterward, again they start correcting as natural progress and take the natural adult pattern of 5-7 degree Valgoid knee. That remains with the life of a person. If this variation in limb alignment persists beyond the age limit and of a high grade of deformity, then we need to identify the cause and treat them.
Other Causes of Bow Leg in children:
Ricket (Vitamin D Deficiency)
Skeletal dysplasia (abnormal bone development)
Growth plate injury
Other Causes of Knock Knee in children:
Growth plate injury
Normally infant’s legs are bowed but if it looks beyond normal then parents should consult a pediatric orthopedic surgeon or pediatrician. We need to have a close watch on the progress of bowing. If the knock knee persists beyond 7-year age the parents also need to consult a specialist.
Parents can easily recognize the bowing as well knock knee just by looking at the leg without cloths. In the bowleg, the tibia is bend outward so that space between knees is more compare to space in normal children. In knock knee, it is reversed. In this condition, both side knees touch each other in a standing position.
Primary diagnosis can easily be made just but examination of the child in standing position & exposed both lower limb. The first investigation is an x-ray if it is needed. In X-ray, we can determine the etiology. X-ray antero-posterior view of the lower extremity is required which should be taken in a standing position. It will give a clearcut diagnosis and severity of the deformity. Blood tests are required to see the level of Vitamin D.
Physiological variety of both bow leg and knock knee doesn’t need any treatment except assurance to parents. If the bowing is more and occurs because of vitamin D Deficiency, then needed vitamin D and calcium supplement? Usually, this bowing & knock knee correct spontaneously if dx in the early age group. Sometimes deformity is sever but bones is soft then plaster or mermoid brace should be given to the child.
When the deformity is severe and age is beyond 7 year in knock knee or 3 year in bowing of tibia then child need surgery to correct the deformity. Pediatric orthopedic surgeon will do surgery after evaluation. If the child has sufficient growth with him then the doctor will modulate physial plate growth by 8 plates or screw and if the child is crossed their growing age then cutting of the bone and correcting the deformity at once.
Blount disease requires special consideration in treatment planning but beyond discussion at this place.