Physiological development
Coronal alignment normally changes with growth:
- infants are relatively varus
- alignment becomes neutral at approximately 2 years
- valgus peaks around 3–4 years
- gradual correction then occurs toward the normal adult pattern
Persistent or progressive valgus after the expected physiological period requires assessment.
Causes of pathological genu valgum
- skeletal dysplasia
- metabolic bone disease, including rickets
- physeal injury after trauma or infection
- tumour or physeal bar
- obesity-associated deformity
- post-traumatic overgrowth or malalignment
Assessment
- symmetry
- intermalleolar distance
- mechanical axis
- limb length
- rotational profile
- joint stability
Imaging
Obtain a standing long-leg AP radiograph when deformity is excessive, asymmetric, progressive, associated with short stature, or outside the normal age range.
Important measurements include:
- mechanical lateral distal femoral angle
- medial proximal tibial angle
- mechanical axis deviation
Treatment
- physiological valgus: observation
- treat metabolic or systemic cause when present
- guided growth for a skeletally immature child with progressive deformity
- corrective osteotomy when growth remaining is insufficient or deformity is severe