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©2013 UpToDate ® Print Email Differential diagnosis of bowed legs Condition Possible clues to the diagnosis Physiologic bowing Age <2 years; bilateral and symmetric; involves the femurs and tibias; normal stature; no lateral thrust during ambulation; improves with age Pathologic bowing Short stature, intercondylar distance >6 cm when the legs are held with the patella facing forward and the medial malleoli touching Blount disease Asymmetry; focal angulation of proximal tibia; lateral thrust during ambulation; radiographs with medial beaking and downward slope of proximal tibial metaphysis and epiphysis Rickets Nutritional rickets Breast-fed infant with inadequate supplementation of vitamin D; decreased serum calcium and/or vitamin D; widened physes and flared metaphyses X-linked dominant hypophosphatemic rickets (OMIM #307800) Growth retardation, rachitic and osteomalacic bone disease, hypophosphatemia, renal defects in phosphate resorption and vitamin D metabolism; widened physes and flared metaphyses may or may not be present Skeletal dysplasia Characteristic clinical and radiographic features vary according to the dysplasia. Most children with skeletal dysplasia do not present solely with bowed legs. Some examples of additional manifestations are provided below. Achondroplasia (OMIM #100800) Short stature; rhizomelic shortening of the limbs; frontal bossing; midface hypoplasia; lumbar lordosis; elongated fibula; trident hand Pseudoachondroplasia (OMIM #177170); associated with knock-knees in some patients Autosomal dominant inheritance; short-limb dwarfism with onset by 2 years; joint laxity; vertebral anomalies Metaphyseal chondrodysplasia (multiple types) Persistent bowing and short stature Multiple epiphyseal dysplasia syndrome (OMIM #132400) Autosomal dominant inheritance; mild short-limb dwarfism; brachydactyly; small, irregular epiphyses on radiographs Cartilage hair hypoplasia (OMIM #250250) Autosomal recessive inheritance; short-limb dwarfism; fine, sparse hair; sparse eyebrows, eyelashes, and beard; short hands Asymmetric growth Fracture History of fracture Sepsis and DIC (eg, meningococcemia) History of infection Neoplasia (eg, focal fibrocartilaginous dysplasia of proximal tibial metaphysis) Progressive, unilateral deformity; radiolucent, well-circumscribed lesion, often with rim of reactive bone OMIM: Online Mendelian Inheritance in Man. Data from:

Asymmetric growth Fracture History of fracture Sepsis and DIC (eg, meningococcemia) History of infection Neoplasia (eg, focal fibrocartilaginous dysplasia of proximal tibial metaphysis) Progressive, unilateral deformity; radiolucent, well-circumscribed lesion, often with rim of reactive bone OMIM: Online Mendelian Inheritance in Man. Data from: Schoenecker PL, Rich MM. The Lower Extremity. In: Lovell and Winter's Pediatric Orthopaedics, 6th ed, Morrissy RT, Weinstein SL (Eds), Lippincott Williams & Wilkins, Philadelphia 2006. p.1158. The knee and leg. In: Mihran O. Tachdjian. Clinical Pediatric Orthopedics: The Art of Diagnosis and Principles of Management. Appleton & Lange, Stamford, CT 1997. p.87. OMIM Online Mendelian Inheritance in Man (www.ncbi.nlm.nih.gov/omim/).