Why do professional footballers suffer osteoarthritis?
As a new study suggests knee surgery is a contributory factor in increased levels of osteoarthritis among retired footballers, we ask whether the report is taking too narrow a view.
This week, the World Cup in Russia draws to a close. At time of writing, England are still in the competition and there is a real chance that football might actually come homeTM – a fact that’s being attributed to everything from our sudden discovery of how to take set pieces, to Gareth Southgate’s waistcoat, to the youthfulness of the squad.
Yet once that squad is no longer quite so youthful, there’s a real danger osteoarthritis (OA) could be a fact of life for many of them. The risk of general injury to a professional footballer is 1,000 times greater than those in other high risk lines of work. A squad of 25 footballers will likely experience between four and eight knee injuries a season. And the risk of an ACL injury is 20 times greater during a game than in training.
Given the above, and the day-to-day pounding a footballer’s knees face, it’s perhaps hardly surprising that professional footballers are more likely to face OA (the wearing down of the cartilage-like material within the knee) once their career is done – and sometimes even during it.
Yet a new study suggests an additional contributory factor to developing OA: knee surgery. It’s a conclusion we’re not convinced quite stands up to scrutiny.
Osteoarthritis and knee surgery linked?
The study of almost 1,400 current and ex-professional footballers found that:
“The prevalence of knee OA was higher among retired than among current professional footballers and reached up to 40%… current and retired professional footballers were nearly twice as likely to suffer from knee OA by every additional severe knee injury and by every additional knee surgery incurred during their career.”
Explicit in the conclusion is the suggestion that ex-footballers who suffer from osteoarthritis in later life do so because they have had one or more surgical procedures on their knees. But this is to miss the fact that, usually, post-surgery the footballer will have returned to their sport and continued to place huge demands on their knees.
It’s simply not possible to directly connect the injury and the surgery because the return to sport adds an enormously disruptive factor into the equation.
Drawing causal links that aren’t really there is a common misunderstanding with knee injuries – sporting and otherwise.
Yorkshire Knee Clinic’s knee specialists will often hear patients say something along the lines of: “I’ve heard arthroscopic (keyhole) knee surgery increases the risk of wear,” but the actual evidence to support that is minimal at best.
The reality is that injuring the knee is what increases the rate of wear. That is even more the case when dealing with elite sport.
Hanging the boots up
20+ years ago, when knee surgery was less advanced than it is today, there was a much lower limit to what the knee surgeon could do. More footballers faced career-ending injuries, forced to ‘hang their boots up’ in their late twenties or early thirties.
Today, knee surgeons repair more damage, more often, more successfully. A professional footballer who injures his or her knee today is far less likely to face that ‘hanging the boots up early’ moment. They will play on, often into their mid-thirties or later, subjecting their knees to more wear and more injuries.
In that rather oblique sense, you could perhaps argue that knee surgery does lie at the heart of OA in retired professional footballers. Knee surgeons are, after all, creating the environment for a footballer to keep adding to the levels of wear.
Yet here again, this puts the knee surgeon at the heart of the issue when many other factors are involved: the club, the coach, the sponsors may all increase the pressure to get back on the pitch sooner rather than later – although no pressure to return to playing is likely to be as great as that coming from the footballer him/herself.
We would argue, then, that knee surgery is far more an effect of wear and injury in retired footballers than a cause of it. Knee surgeons are enablers, helping footballers get back on their feet so they can keep playing. Yes, that may ultimately lead to greater wear on the knee, but blaming the surgery is a little like blaming the garage mechanic for the potholes in the road, on the basis that if fewer cars were fixed the wear and tear on the tarmac would be less.
The positive from all of this, of course, is that we are far better able to protect against the effects of wear than we once were. ‘Salvage’ surgery (partial knee replacements, total knee replacements, cartilage replacements etc) is now so good that we can usually reduce the effects of wear or often return the knee to (near) normal function once OA is diagnosed.
That does not mean that knee surgeons do not have a duty to warn athletes against the potential detrimental effects of continuing with sport after knee surgery. Nor, we would suggest, does it mean that knee surgery should take the blame for what is invariably a far more complex issue.