Knees put up with a huge amount of strain during most types of activity. So what are the most effective treatments when running injuries occur?

Running is good, if your knees are up to it

Some people like to run. If you’ve got the genetics of Mo Farah then you could probably run thousands and thousands of miles, and as long as you’re lucky, your knees would probably be fine. We’ve all heard the research headlines that running is good for your knees and that it doesn’t cause arthritis. But is that really true, and does it really apply to us all?

If you’ve got normal tyres on your car, then you can drive nice and fast for good long distances. If your tyres are bald, then you might get a blowout. If your car’s shock absorbers are knackered and if you drive at speed along cobbles, then your car will probably fall apart, etc. etc.

The analogy for knees really isn’t all that different.

If you’re overweight, either through obesity or because of your natural shape because of your genetics, then you’re simply not ‘built’ for running.

If your meniscal cartilages are torn or missing, then you’ve lost your shock absorbers, and you’re simply no longer suited to running.

If your articular cartilage is wearing thin or if it’s worn away down to bare bone, and if you then run, you’re simply going to cause more damage.

And so the list goes on.

So, running with normal knees is good, but running on bad knees is bad, and it’s quite frankly just silly!

Runners are a funny lot!

Most people who run regularly share a number of particular traits:

• they’re usually skinny
• they are fit
• they have more energy
• they are more positive, and have a lower incidence of depression
• they love running
• they are obsessed!

They are obsessed with running, but they also obsess with all the many things that are associated with running, including:

• footwear
• running style
• diet
• supplements
• lycra!

And what’s the best way to make a runner hate you (or at the very least, stop listening to you and ignore all your good advice): tell them to stop running!

The positives of running

The list is long, and it includes:

• reduced risk of heart attack
• reduced risk of stroke
• reduced risk of diabetes
• reduced incidence of depression
• reduction in stress
• improved cognitive function and memory processing and storage
• higher pain threshold
• living longer and living better!

On top of all this, running is cheap and convenient.

Runners can actually feel somewhat cleverly smug about things, as the research is actually in their favour. Nokia et al published a study in The Journal of Physiology in 2018 looking at the effects of exercise on rats. 88 rats were taken and split into groups:

• 1) Sedentary
• 2) Weight-lifting
• 3) HIIT training
• 4) Long distance running

They studied the amount of Brain Derived Neurotrophic Factor (BDNF) released from each rat’s hippocampus in the brain. BDNF has been shown to increase the number of neurones in the hippocampus, and it is the hippocampus that aids in the storage of new memories, keeps new and old memories distinct, allows flexibility in the use of existing memories and assists the processing of new information (i.e. the hippocampus is kind of important, if you want to avoid depression and anxiety and if you want to improve mental performance).

The rats were examined after 7 weeks of exercise, and Nokia et al.’s results showed the following:

• No change in the sedentary group.
• The weight-training group gained muscle mass and strength, but there was no increase in BDNF.
• The HIIT group showed some increase in BDNF.
• The biggest increase in BDNF by far was in the runners! – and the greater the running distances, the bigger the increase in BDNF.

Therefore, running is actually good for your brain, not just your overall physical health.

So, it really can take quite a lot for someone like me to advise someone who runs to ‘not run’!

The most important thing is to listen to your body and to listen to your knees. For muscles, it’s true: no pain, no gain. However, for joints it’s the opposite. If your knee hurts then this is a sign that there’s a problem, and like many problems in life, the longer you ignore them with your head buried in the sand, the worse they get.

There are three broad categories of knee problems that I see in runners, and these are:

• 1) Over-use ‘injuries’, where the pain is coming from tissue inflammation.
• 2) Traumatic damage, where a specific structure in the knee is damaged.
• 3) ‘Wear and tear’, progressing from early degenerative changes to fully-blown arthritis.

Over-use injuries

This is where something is either rubbing, or where the tissues just aren’t able to cope with the stresses that are being placed on them, which tips the balance into negative in the ongoing damage-repair cycle.

This group includes conditions such as:

• ITB Friction Syndrome
• patellar tendinopathy
• medial plica syndrome
• fat pad inflammation

Broadly speaking, the best management of these conditions is:

• (i) See a specialist.
• (ii) Have appropriate imaging with an MRI + also an ultrasound scan, to A) confirm the diagnosis, but also B) to double check for any other potential intra-articular pathology.
• (iii) Rest!
• (iv) Take anti-inflammatories and try icing the knee.
• (v) Manual therapy.
• (vi) And then, if things still fail to settle, one can then consider other non-invasive treatment options, such as ultrasound-guided injections or shockwave therapy – and these normally fall under the remit of our colleagues, the Consultants in Sport & Exercise Medicine.

In these conditions, surgery is only rarely ever necessary.

Traumatic injuries

Fortunately, we see relatively little knee trauma in runners. It’s fairly rare for a runner to trip and fall and end up accidentally twisting their knee and causing major damage, such as ligament ruptures. However, one type of trauma that I do see on occasions is traumatic patellofemoral articular cartilage damage.

If a runner falls, and if they fall forwards landing on the fronts of their knees on hard concrete, then this exerts massive blunt trauma to the front of the knee, with impaction of the patella onto the front of the trochlear groove at the front of the femur.

If there’s a haematoma in the soft tissue at the front of the knee, or pre-patellar bursitis, this can be extremely painful, but these issues are just superficial and they normally tend to settle down on their own, mostly without the need for specific intervention.

If, however, there is severe enough compressive blunt trauma to the articular cartilage in the patellofemoral joint at the front of the knee, then this can sometimes cause acute damage to the articular cartilage (which will normally show up on an MRI scan). This can sometimes need early surgery.

If, however, an MRI scan shows significant patellofemoral bone bruising but no actual articular cartilage damage, then this may not actually be as genuinely reassuring as one might first think – because even if the articular cartilage initially remains intact, it can suffer delayed failure afterwards: sometimes months or even years later. Therefore, this kind of injury is certainly one to take seriously.

‘Wear and tear’

The main things that ‘wear’ in a knee joint are:

• the meniscal cartilages
• the articular cartilage

Meniscal tears

The meniscal cartilages are two elastic C-shaped wedges of cartilages in the knee that sit in-between the femur and the tibia, and that act primary as load sharers. (They used to also be called ‘shock absorbers’, although biomechanically speaking, this has rather been disproven now). As one gets older, the meniscal cartilages also get older, which means that they gradually become less elastic, more friable and more liable to tear. Importantly, 50% of degenerate meniscal tears occur spontaneously, with no history of any trauma at all.

Not all degenerate meniscal tears will end up needing surgery. However, recent ill-informed trash-talking in some of the medical press (note, medical not surgical – i.e. they are commenting on a subject in which they are not actually specialists, let alone experts) has suggested that ‘knee arthroscopy doesn’t work’ and that surgery for a degenerate meniscal tear is no better than placebo – this is just simply wrong! What’s actually important is appropriate patient selection.

If a patient has:

• just minor symptoms,
• minor, minimal or no actual functional restrictions,
• no mechanical symptoms, such as giving way or locking,
• if their symptoms are beginning to get better with time

then the correct management is to offload and protect the knee, and to wait and watch and just give things time, and just see how things go (i.e. conservative management).

With this ‘wait and watch’ approach, some people might actually end up needing surgery, but many will do well enough to manage without.

If, on the other hand, the patient has:

• sudden sharp pains,
• painful clicking / catching (not just painless clicking),
• giving way or locking,
• significant functional restrictions and/or
• significant symptoms that are not getting better with time, or that are actually getting worse

then in that case it is entirely appropriate to go ahead with an arthroscopy, in order to trim the torn degenerate meniscus smooth and stable (degenerate tears are rarely ever repairable). Importantly, trimming a torn meniscus cures the symptoms from a meniscal tear but it does not, of course, restore the function back to the damaged meniscus.

It is said that trimming a meniscus ‘causes arthritis’ – this is just not true. It’s correct that if you remove normal healthy meniscal tissue then you’re defunctioning the meniscus, and that would then increase the risk of arthritis in that knee in the longer-term future. However, removing an intact (or a repairable) meniscus would be just daft, and completely wrong!

If a meniscus has developed a degenerate tear, then the torn tissue has already lost its function. Therefore, trimming away just the torn defunctioned tissue (in order to eliminate the symptoms of the tear) does not defunction the meniscus any further, as the damage has already been done.

What is particularly important with runners, however, is to have a clear understanding of just how badly a meniscus might have been damaged / defunctioned / lost – as the less of a meniscus one has in one’s knee, then the more important it is to protect the joint from heavy / repetitive impact, and hence the stronger the argument is for advising against continuing with long-distance running.

Articular cartilage damage

If one is developing ‘wear and tear’ (degeneration / thinning / loss) of the articular cartilage on the surface of a knee joint, then this is a clear sign that the knee is becoming ‘arthritic’. If you continue to pound a damaged joint, then you’re simply going to make the damage worse, speed up the degenerative process, and bring forward to time when you’re likely to end up needing major surgery, with an actual knee replacement.

And you should NOT run on an artificial knee replacement prosthesis!

Conclusions

So, there are times when the correct advice to a runner is that they should actually just simply give up running! This does not really mean ‘giving up’ – what it actually means is adapting, and focusing primarily on light non-impact cardio fitness work instead, such as the exercise bike / cycling, the cross-trainer, the rowing machine and light weights – all of which are good for your heart and your health, whilst being light on and relatively safe for your knees.

Most importantly, you can’t (or at least shouldn’t!) talk about treatments for a knee without first having a clear and specific diagnosis. It’s pretty much impossible to have a firm and confident diagnosis without first looking fully at the knee, and it’s impossible to see exactly what’s going on inside a knee joint just by looking from the outside, and hence if you want to do things properly then you’re going to need to get some imaging. The gold-standard for imaging of a knee is an MRI scan.

An MRI scan may give you a list of various potential diagnoses, but it is not the be-all and end-all in itself, as it’s important to ‘treat the patient, not the picture’. However, the old adage of ‘look before you leap’ is highly apposite here, and you can’t see without looking. So, if you think you might have a knee problem, then get it checked out! See a proper specialist and get some decent imaging: if it’s all fine, then great. If there’s something wrong, then the sooner you know and the sooner you deal with it, the better!

Look after your knees!!

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If you’re a healthcare professional who is interested in running injuries, then check our marathon injuries webinar available on-demand.

About the author

Mr Ian McDermott is a Consultant Orthopaedic Surgeon specialising purely in knees. He is the founder and the Managing Partner of the London Sports Orthopaedics practice, based in the heart of The City of London, and he is also an Honorary Professor Associate in the School of Sport & Education at Brunel University.

Ian won the President’s Medal of the British Association for Surgery of the Knee for his research into meniscal repair, and he was awarded a Master of Surgery higher degree by Imperial College for his research into meniscal transplantation. Ian has Hospital Innovations ‘Centre of Excellence’ status for meniscal transplantation, and he also has Vivostat ‘Centre of Excellence’ status for his use of biological glues in knees.

Ian has also pioneered the use of custom-made knee replacements in the UK, and he is part of the Conformis Surgical Visitation Program, teaching surgeons from across the UK on the surgical techniques for custom-made knee replacement surgery.

Ian was also the youngest ever surgeon to be elected as a Trustee and Council Member of the Royal College of Surgeons, he is currently the President of the UK Biological Knee Society, and he is also the Vice-Chairman of the Federation of Independent Practitioners Organisations.

Ian has said that he would welcome any comments or queries relating to his article, or any queries on any other knee-related topic. He can be contacted via:

www.kneesurgeon.london

www.sportsortho.co.uk