Childhood obesity and SCFE

Almost every week we learn more about how obesity is affecting children, and how it is becoming more common.

A recent study, in the medical journal 'New England Journal of Medicine' highlighted how obesity develops right at the beginning of life - with most children becoming obese somewhere between 2 and 5 years old. Now, I’ve published in the journal Pediatrics that amongst almost 40,000 children in Scotland, that if they are obese at 5 years old, then there is a 75% chance that they will still be obese at 12 years old.  

But why is this relevant to me, a children's orthopaedic surgeon? 

There are several diseases of children’s bones linked to obesity, but the most important is almost certainly ’Slipped Capital Femoral Epiphysis (SCFE)'. In this disease the ball, of the ball and socket joint of the hip, slips out of place. It does so commonly because the hip cannot withstand the weight of the obese child. We’ve shown that obese children have almost a twenty times greater risk than thin children of developing SCFE.  This sometimes occurs gradually with a child limping or having knee or hip pain over many months. Sometimes it happens suddenly with the child collapsing in severe pain, often after a trivial injury, and being unable to walk. 

We always perform surgery to screw the hip back together. This is done with a general anaesthetic with the child asleep. Typically, the bigger the degree of slip, the bigger the surgery. 

The problem with this disease is that it makes the hip change shape, even with surgery. An altered hip shape means that the hip grinds as it moves, and this expedites the development of arthritis. In the very worst cases as the hip slips out of place the blood vessels which feed the hip are torn. In these cases the hip dies and collapses. These children will develop very severe pain and often need a hip replacement in their teenage years. Whilst a hip replacement is a good operation, it significantly limits an individual's activities and opportunities in life, and frequently leads to many more surgeries throughout adulthood.

How can we change this?

Whilst limiting the amount of obesity is obviously a major public health concern, specific steps related to this disease are also important. Most crucially it is important that doctors and healthcare professionals recognise the existence of SCFE. On average, after a child has developed symptoms, the time to diagnosis is about six months, frequently with many attendances to healthcare professionals. Over this period the hip problem frequently worsens, the surgery becomes more complex and throughout this period there is a risk of a catastrophic sudden slip. 

Healthcare professionals need to be alert that hip, knee or thigh pain in an adolescent child frequently indicates a hip problem - the knee and hip have the same nerve supply therefore children often complain entirely of knee pain! In these cases it is really important to carefully examine the hip (particularly the inward rotation of the hip). Any difference between the two sides could indicate a problem. Furthermore, if there is any doubt the healthcare team should arrange an X-ray of the hips with a side-view of the hips being most important (also called a Frog View). An x-ray is far more useful than any advanced imaging (i.e. MRI scans).

So my message to any healthcare professionals is -  Amongst adolescent and pre-adolescent children (especially obese children over 9-years old) with knee or hip pain, carefully examine the hips for asymmetry or restricted internal (inward) rotation. If there is any concern or doubt arrange a lateral (frog) radiograph. SCFE should always be sent immediately to a surgeon (ideally with an interest in children’s orthopaedics). The earlier the disease is diagnosed, the simpler the surgery to screw the hip back together and the lower the risk of arthritis.