Obesity – is it always the cause of joint wear?

As a new report shows that childhood obesity levels are leading to hip replacements in children as young as ten, Yorkshire Knee Clinic’s Dave Duffy explains why weight is only one part of the jigsaw.

Last month, an article in the Telegraph raised the issue of joint replacement surgery in the young caused by obesity. It’s worth noting that the headline is a little more alarming than the statistics. Whilst there has been a 60% increase in obese patients seeking joint replacement surgery, only ten 10-19 year olds have had knee or hip replacement surgery since 2014, while 11 twenty-somethings had knee replacement surgery over the same period. Hardly an epidemic, but clearly concerning.

And yet, in any report of this kind, the focus inevitable falls on the weight, when other factors may be at play.

Any knee symptoms will be influenced by three elements:

1. The pathology, effectively, what is the problem inside the joint?

2. The load the knee has to carry: whatever’s above it.

Greater weight, on the face of it, will increase the load, but things are never quite so simple. A sedentary person on even the most damaging of diets may put less load through their knees than someone who, for example, runs or jumps regularly. With impact sports a person will typically put eight times their bodyweight through their knee during activities. How much damage that causes them depends on the third element:

3. Your ability to control that load

This is a combination of muscle strength and endurance. For example, you may have the strength to do 5 squat thrusts, but you may not have the endurance to do 100.

Weight inevitably increases the load going through the joint, so it stands to reason that weight will also accelerate damage in the absence of the strength and endurance to manage that load.

Childhood obesity may well play a part in the above statistics. But it is only one part of a considerably larger jigsaw, and it would be wrong to assume that obesity is the cause of a joint replacement, when other factors may be at play. Obesity is, however, likely to be a contributor.

To date, Yorkshire Knee Clinic’s knee surgeons have yet to carry out a knee replacement on any obese child. With surgery always the final option to be chosen once all non-operative routes have been tried (because of the reduced risk), our preferred route would be to try weight loss, activity modification, pain management and and/or physio ahead of any surgical option.

Are you or your child suffering knee pain? Talk to the knee specialists at Yorkshire Knee Clinic now.

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