Runners have a complex relationship with their knees. On the one hand it’s become such a commonplace assumption that the sport is bad for the knees that there’s an injury called “runner’s knee”; on the other is a decent body of evidence suggesting that running is actually good for the knees, with a 2013 study on 75,000 runners and almost 15,000 walkers finding that the former were significantly less likely to develop arthritis.
Given that being obese is the biggest cause of knee osteoarthritis, it’s not surprising that people who undertake an activity that keeps you trim find it’s good for their knees. However, that’s not going to be much solace to anyone who is already suffering from runner’s knee, and it’s certainly still wise to keep tabs on your knees (and every other part of the body) for any niggles when you’re training regularly. That’s especially true if you’re suddenly doing a lot more running than you have done in the past as part of a training plan ahead of a big event like the London Marathon.
If you’re taking on such a plan and do have concerns about your knees, you’ll want all the info you can get on preventing runner’s knee, as well as what you can do about it if it does strike. Here’s Ian McDermott, a consultant orthopaedic surgeon who specialises in knees and sports injuries, with everything you need to know.
What is runner’s knee?
“Runner’s knee is actually a bit of a made-up term,” says McDermott, “and it’s certainly not an actual proper medical diagnosis.
“Experts use the phrase ‘patellofemoral pain syndrome’, which means the same thing: pain at the front of the knee or knees linked to running. It’s an extremely common problem.”
If you have such pain, and it’s severe, the most important thing might actually be a proper diagnosis beyond runner's knee.
“Pain at the front of your knee – anterior knee pain – is just a symptom,” says McDermott. “If your symptoms are more than just a niggle then you should really seek a proper diagnosis. So the right question to ask is, ‘what’s actually causing my knee pain?’”
What are the symptoms of runner’s knee?
The clearest symptom of runner’s knee is pain, usually in the form of an intense ache at the front of the knee around the kneecap.
“This pain tends to come on not immediately as you start running but part way through a run,” says McDermott, “and it generally gets worse the longer you continue. The knee often particularly hurts after a run.”
Another big symptom is swelling, as McDermott explains.
“If the articular cartilage layer covering the surface of the bones in the joint becomes badly damaged from wear and tear due to excessive loading, this tends to cause intermittent swelling in the knee.
“Swelling in the joint can make the knee feel tight and stiff, and the most obvious place where you might see the swelling is directly above the kneecap – the suprapatellar pouch.
“It’s not the swelling itself that’s the actual problem: the swelling is simply a sign that there’s an underlying issue with possible damage in the joint itself, which is why just aspirating the joint [sucking out the fluid with a needle and syringe] is rarely ever the answer to the problem.”
What causes runner’s knee?
There are several underlying factors that can combine to cause runner’s knee.
“Pressure overload and eventually damage to the cartilage in the patellofemoral compartment at the front of a knee tends to be a multifactorial thing,” says McDermott. He lists the possible factors:
- excessive internal rotation in the hip joints
- weak glute muscles
- a tight iliotibial band (ITB), the ligament that runs down the outside of the thigh
- knock knees (AKA a valgus posture in the knee or medial knee displacement)
- feet that point outwards too much (excessive external tibial torsion)
- flat feet or dropped arches (planovalgus foot posture)
- the kneecap running too far towards the outer side of the knee instead of in the middle of the trochlear groove at the front of the knee (lateral patellar maltracking), and/or an L-shaped or flat patella instead of the normal V-shaped patella (patellofemoral dysplasia)
“On top of all this,” McDermott says, “some people suffer cartilage damage at the front of their knee from trauma, such as a fall onto a hard surface.”
Another potential factor is genetics, so if your parents, grandparents and great-grandparents all have dodgy knees, that’s probably not a good sign.
“Some people are just born to run forever,” says McDermott. “Other people may have one or more underlying potential issues that predispose them to having issues with their knees. If they are gentle with their knees and don’t overload them, then they might be fine and have no significant issues throughout their entire life.”
Unfortunately, running is one thing that ramps up the pressure on your knees.
“When you land on foot leg with the knee bent while running, the loading forces in the patellofemoral joint at the front of the knee can be up to seven times your bodyweight, which is massive,” says McDermott.
“So the real surprise is that more people don’t end up with knee pain from running!”
How to avoid runner’s knee
You’ve read a lot of bad news up to here, but don’t despair. If you suspect you have dodgy knees and have already signed up for a marathon, there are ways to avoid the pain.
“The best advice that I can give is to take your knees seriously,” says McDermott.
“If you have any concerns about symptoms linked to running, start by ensuring that you’ve got the best and most appropriate running shoes. This means seeing someone with specific expertise in assessing foot posture and providing proper supportive footwear that suits your particular needs.
“Going hand in hand with this is getting a full and detailed biomechanical assessment with gait analysis, from a senior experienced qualified physiotherapist or biomechanist.”
Once you’ve got the right running shoes it’s time to focus on your training. You need to give yourself as much time as possible.
“If you’re training for an event then you should give yourself plenty of preparation time,” says McDermott, “so that you can slowly and gradually ramp up your distances without unduly overloading your knees with too much too fast.”
How to treat runner’s knee
If you’ve already succumbed to what you fear might be runner’s knee, the first thing to do is get a proper diagnosis of the problem, says McDermott.
“You can’t really talk about treatment until you’ve got a clear and specific diagnosis. If you’re getting any significant symptoms in your knees, go and have a proper assessment from either a physio or a knee specialist.”
Drastic cases might require surgery, but for most people a physiotherapist will be able to help with the problems.
One thing to remember – do not do lower-body exercises that put pressure on the knees.
“Unfortunately too many people with runner’s knee end up being told to do loads of squats and lunges,” says McDermott.
“This seems a bit crazy, given that this increases patellofemoral loading and all too often simply aggravates the person’s symptoms.”
Resting up is key and the muscles you do need to focus on are your glutes, McDermott says.
“What’s often required is a period of relative rest combined with specific exercises to strengthen up your glutes, to stretch out your ITB and to build up the inner part of your quads [your VMO], combined with ensuring that your alignment, posture and running style is fully optimised.”
How long will runner’s knee stop you from running?
As you'd expect, this depends on the severity of your problems. It could be case of reducing your running a bit, but you might need to stop altogether to avoid future problems.
“For some people, all they might require is to cut down their mileage a bit,” says McDermott. “Mix in some cycling and the cross-trainer, and then slowly ramp things back up.
“For others, there could be significant damage inside the knee joint, in which case it might be a really bad idea to continue running – you might simply be storing up severe problems for the future.
“This is why it’s very important to pay attention to your knees, to take any symptoms seriously and, if your knees don’t feel right, to get them checked out. A bit of time and effort up front could save you years of pain in the future.”
Nick Harris-Fry is a journalist who has been covering health and fitness since 2015. Nick is an avid runner, covering 70-110km a week, which gives him ample opportunity to test a wide range of running shoes and running gear. He is also the chief tester for fitness trackers and running watches, treadmills and exercise bikes, and workout headphones.
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