Intended for healthcare professionals

Clinical Review

Normal lower limb variants in children

BMJ 2015; 351 doi: (Published 07 July 2015) Cite this as: BMJ 2015;351:h3394
  1. Andrea Yeo, fellow in paediatric orthopaedics,
  2. Kyle James, consultant paediatric orthopaedic surgeon,
  3. Manoj Ramachandran, lead consultant paediatric orthopaedic surgeon
  1. 1The Royal London & Barts and The London Children’s Hospitals, Barts Health NHS Trust, London E1 1BB, UK
  1. Correspondence to: A Yeo andreayeo{at}

The bottom line

  • Musculoskeletal symptoms are one of the leading reasons for visits to general practitioners, with over 10% of children presenting for medical attention each year

  • Common reasons for referral include intoeing, flat feet, knock knees, and bow legs—all normal variants in growing children

  • Additionally, vitamin D deficiency and obesity in children are on the increase, with well documented associations with musculoskeletal disorders ranging from chronic conditions such as rickets with resultant bow legs or knock knees, to more acute conditions such as slipped capital femoral epiphysis

  • Recognising developmental norms and differentiating them from disease may help allay parental anxiety, ease referrals to primary and secondary care, and prompt appropriate timely referrals for abnormal conditions

Bow legs, knock knees, flat feet, intoeing, and out-toeing gaits in children are common but often cause undue parental anxiety, prompting frequent visits to general practice.1 2 3 4 5 A substantial proportion of referrals to paediatric orthopaedic clinics consist of normal physiological variants in growing children. Careful history, examination, and knowledge of the clinical course of rotational and angular deformities allow accurate assessment of children and provide reassurance to parents. Our review aims to assist general clinicians in recognising normal physiological variants in the lower limbs of children and to identify abnormal features that require specialist attention.

Sources and selection criteria

We searched PubMed and Google Scholar using the terms “p(a)ediatric”, “lower limb variants”, “intoeing”, “out-toeing”, “pes planus”, “flat foot”, “genu varum”, “genu valgum”, “vitamin D deficiency”, “obesity”, and “sporting activity”. The search was conducted from inception of databases to March 2015. Wherever possible we used evidence from randomised controlled trials, systematic reviews (including Cochrane reviews), and expert review articles published in the past 10 years. Current relevant Department of Health policies were also included.

Why are normal limb variants important?

Musculoskeletal symptoms are one of the leading causes of visits to primary care doctors …

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