In the last post, I showed a diagram of growing legs and made the bold statement that in general, funny shaped legs are normal in children. I gave a few red flags to help anyone wanting to know what was probably not a normal pair of growing legs. This time I will go into more detail about some of the specific presentations. I will avoid the child with the mysterious limp, as that post is still to come. Shrodinger's safeguarding rules apply where appropriate.
Bandy knees or ‘bow legs’ (Genu varum)
This is a normal part of development and usually resolves by the age of three years old. It is wise to consider risk factors for vitamin D deficiency. Bow legs may be part of a picture of vitamin D deficiency, but on their own in a healthy growing child do not indicate rickets. Children with bow legs should be referred if it is painful or asymmetrical, or the child is over 3 years old and the angle is worsening. Also refer if there is developmental delay, abnormal growth velocity or other musculoskeletal abnormalities. If there are risk factors for or evidence of vitamin D deficiency, please check levels as well as referring.
Knock knees (Genu valgum)Having knock knees is fairly common in mid-childhood. The appearance of the knees should be symmetrical. In most cases it is appropriate to reassure that it can be observed until adolescence. You should refer if affecting activities, the knees appear to be asymmetrical or if the angle worsening in a child over 8 years old.
An in-toeing gait is usually due to a persistent twist of the femoral head. As a result the internal rotation affects the entire lower limb so that the knees are also pointing inwards. There is usually no associated pain and the problem resolves spontaneously in 90-95% by late adolescence. Reassure in most cases after checking that the knees are also internally rotated. Refer if painful, progressive, asymmetrical or there is hypertonicity
Another cause of in-toeing is metatarsus adductus (a turning in of the bones at the midfoot) which causes in-toeing at birth. This, like talipes, can be observed if flexible and can be gently returned to an anatomical position while examining. Talipes and metatarsus adductus are both risk factors for developmental dysplasia of the hip.
Most children who tip-toe do so as a normal variant stage of development (a bit like bottom shuffling) and will progress to a normal gait over time. Assess the child’s global development, examine the spine, passively extend the ankles, assess muscle tone and ensure that the gait is equal. In most cases you can reassure reassure. I recommend referral if tiptoeing is unilateral or asymmetrical, there is increased muscle tone, the ankles cannot extend, there is a spinal abnormality or developmental delay.
Hypermobility in children is a complex issue. Joint hypermobility on its own is very common and is essentially normal. Children are much more flexible than adults and so the prevelance of hypermobility, using standard diagnostic criteria is as high as 30%. (1) Of course many older children use this to their advantage, becoming top athletes or dancers.
There are however, a small number of children who have an underlying syndrome. The prevalence of normal hypermobility makes these children very difficult to identify. Furthermore, there seems to be a great deal of debate about where to draw the line between normal variant and clinical syndrome. What I have been told by Rheumatology colleagues is that the danger lies in seeing hypermobility as a disability, since reducing activity is likely to worsen any symptoms and may contribute to obesity, itself a risk factor for joint problems. If a child has minimal symptoms, the British Society for Paediatric and Adolescent Rheumatologists recommend (2) that the term 'Connective Tissue Advantage' is used. As well as useful tips for patients and clinicians, there is also a comprehensive guide to spotting other significant clinical features of syndromes such as Elhers-Danlos.
An apophysis is any ossification centre which is under tension (unlike an epyphysis which is under compression) in a growing bone. As such they are prone to over-use injuries, especially during the adolescent period, when bones are growing rapidly and muscles become strong enough to do more damage to the bones to which they are attached.
So, pretty much everything that doesn't limp and isn't hot or swollen is probably normal (or requires supportive treatment only). The key thing is to know what is normal and what is not, as well as understanding what is treatable and what is not.
Next time - the limping child
Disclaimer - I hope that Usain Bolt will forgive me for the use of his image in the name of medical education. I couldn't find a picture of a stick figure with flat feet.
- Benign joint hypermobility in childhood, Rheumatology, Volume 40, Issue 5, Pp. 489-491.
- The British Society for Paediatric and Adolescent Rheumatology, Guidelines for Management of Joint Hypermobility Syndrome in Children and Young People.