Angular deformities around the knee; Genu Varum (Bowing) or Genu Valgum (Knock Knees) are commonly seen as deformities in children. These can be physiological as well as pathological. The newborns have a physiological genu varum which is highest around the age of 1 year and later as the child grows the lower limbs become straight and then further progress to Valgus between the age of 3-4 years. It reaches normal angulation of 7-10 degrees by the age of 7 years.
Causes of Bowing? Knock Knees
- Physiological: As shown in Figure 1
- Pathological: If the Genu Varum persists beyond 2 years, it is considered as pathologic. Few causes are listed below:
- Blood Investigations: Vitamin D3, Sr. Phosphorous, Alkaline Phosphatase, Calcium, Renal Workup
- Radiology: Full-Length Scanogram, Physeal Bar Mapping on MRI for Physeal injuries
- Medical Treatment plainly for Vit D Deficiency Rickets, Hypophosphataemic Rickets, Renal Osteodystrophy
- Bracing: Limited Role – Blount’s Disease
A three-point brace customized as per the child can be used to correct the deformity.
- Surgical Management: Two options are available as per the age at –
Skeletally immature children with at least 2 years of growth left, can be treated with Growth Modulation (Hemiepiphysiodesis), while the skeletally mature children with closed/fused growth plates require Osteotomy & Fixation. In cases such as dysplasia and osteochondroma, surgical treatment is case-specific.
Also known as hemiepiphysiodesis, is a lesser invasive procedure which involves the application of Clips/Bone Staples or Plates on distal femoral physis or proximal tibial physis to control the growth at the Growth plate and thereby correct the deformity gradually. The growth modulation corrects deformities at an average rate of 0.7 to 1.2 degrees per month. (Figure 2) and (Figure 3) The advantage of this procedure is early recovery, no immobilization in plaster, and the child can regain regular activities within a week.
Figure 2: 7-year-old with Genu varum treated with Growth modulation
Figure 3: 11 year old, with severe genu valgum treated with growth modulation
Indicated in skeletally mature children. This is a more invasive procedure that requires correction of deformity acutely at the distal femur or proximal tibia and removing a wedge (Part of bone depending on the degree of deformity) and fixation with a larger plate and screw system or an external fixator. This procedure requires more rehabilitation, a longer period of rest, and non-weight bearing.
Genu Varum and Genu Valgum are common deformities around the knee in children. They need to be addressed so as to maintain alignment and prevent arthritis and injuries in the future. Also, this mal-alignment can interfere with normal walking, running, and sports activities in the children. Timely intervention in terms of investigation and diagnosing the cause and further treatment is important.