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BRITISH BROADCASTING CORPORATION
RADIO SCIENCE UNIT
CASE NOTES Programme no. 6 - Knees
RADIO 4
TUESDAY 6TH MAY 2008
PRESENTER: GRAHAM EASTON
CONTRIBUTORS: MATTHEW BARTLETT
TINA RANGOY
ROB MAST
HILARY PAVITT
DANIEL BYRNE
PRODUCER: PAULA MCGRATH
NOT CHECKED AS BROADCAST
EASTON
Your knee has a tough job. It takes the full weight of your body and it's often under considerable stress. The way it's designed means it's potentially unstable and vulnerable. Not surprising then that when you put your knee through its paces, it can sometimes let you down.
This week a tour through some of the commoner knee injuries and what can be done about them - from high tech surgery to rest and rehabilitation.
CLIPS
He listened intently to me and my life about how active I am - I work as a photographer, I work out, I dance tango - and for this I need my knee to be perfect.
I kind of think it's like you know I'm 46 so my body, I suppose biologically, doesn't want to be running around anymore, does it, but I do.
EASTON
Physical activity may be good for the rest of your body, but your knees can pay the price.
The thigh bone balances on the main shin bone with two crescent shaped shock absorbers, or menisci, sometimes tellingly called footballers' cartilages, in between. Then there are four main ligaments, which along with the muscles around the knee, help to keep it stable.
The two cruciate ligaments form a cross shape inside the joint, and their job is to stabilise front to back and twisting movements of the knee. Then there are the two collateral ligaments - one running down each side of the knee - which give the joint some side to side stability.
These ligaments are easily sprained or overstretched through twisting or wrenching; and sometimes rest, physiotherapy and a little patience is enough to get things on the mend. Matt Bartlett is a consultant orthopaedic surgeon with a special interest in knees, at Northwick Park Hospital in North London.
BARTLETT
As long as the ligament hasn't been stretched out or damaged then yes with rest it will settle down. The ligament injuries - medial collateral - if that's been stretched significantly then really you need to brace the knee to take the stress of it. Most medial collateral ligaments will actually heal up with conservative treatment, i.e. using a brace rather than surgery. The lateral side is a little bit more complex and that's because around the more posterior aspect of that there's an area that control rotation of the knee that we're really only starting to come to grips recently and that needs rather more aggressive treatment, sometimes if there's very significant injury there that will need to be repaired directly.
EASTON
What about physio - because it seems the obvious thing to do if someone's not in too much pain or too much swelling, it's a little bit sore, certainly in general practice one feels perhaps that might help speed things up a bit, even though there's a huge waiting list, particularly in my area, is that something you'd recommend?
BARTLETT
Well physio's a vital part of treatment for knee problems, both pre- and post-operatively and when we can treat injuries conservatively. The issue is really as to whether there's something there that will respond to physiotherapy and that's important to determine right at the outset because there really isn't any point sending somebody for physiotherapy for a long time if it's not going to do any good and they're going to end up in surgery at the end of the process, it's much better then to perform the surgery early, get them to physio afterwards for rehab and that will speed their recovery.
EASTON
What sort of ways could I find out which is which?
BARTLETT
Well it's really looking for red flags, so a lot of swelling of the knee, mechanical symptoms in particular and again very much on the history of the initial injury, if there's a injury that involved a lot of swelling initially then you're thinking that's possibly going to be an ACL injury that might require assessment earlier on.
EASTON
Hilary Pavitt is a keen runner who's started to get problems with her knees. She decided to see physiotherapist Rob Mast from St Leonard's Hospital in Hackney.
PAVITT
So what happens is I can run, they're not painful, I can run and I'm fine but then after I've been running, say about an hour or two later, I work from home so I tend to go for a run in the morning before I go to work and then sit down still in my running gear, I mean I've done my stretches and stuff but then I just go absolutely stiff and I can't walk up and down stairs.
MAST
And that happens after a couple of hours of running did you say?
PAVITT
Well I mean I don't run for a couple of hours but it always happens after a run and then I notice that throughout the whole day I sort of pulling myself up the stairs like an old lady. I'm not in pain but it just really, really aches and they're really stiff and they just don't seem to work.
MAST
And where do you feel the pain in your knees?
PAVITT
Around sort of here underneath the cap and round to the side there and at the back, so the whole - this one mainly. I mean this one's been bad for a few years in that we bought an automatic car, the last car we got, because I couldn't do - I used to get real pain from doing the clutch.
MAST
And have you had any treatment for this?
PAVITT
No. I went to the doctor's once and she said it was something that the muscle there at the top of my knee wasn't strong enough and that's why they were aching and to work on that. But then that was it really, I was kind of dismissed.
MAST
And you haven't seen a physiotherapist before for this?
PAVITT
No. But it's just kind of gotten worse, which is why I've decided to do something about it. I kind of think it's like, you know, I'm 46 so my body I suppose biologically doesn't want to be running around anymore does it but I do. And I've got two young children and I still want to be active and that's the thing, so it's this whole thing of trying to find a way of managing this. And I'm not going to break any records running anymore, I don't care - I love it and it just does so much for me that I don't want to give it up.
MAST
I think if you've done this all your life then I don't think there should be a particular reason to say well you have to pack it in just because you get older, you probably do require a bit of - a least advice and perhaps some physiotherapy treatment. Let's have a look at it. Okay, my hands are a bit cold. Okay can you tighten your muscles? Okay, good and relax. Now just feeling for temperature which is not there and just having a look to see if there's any swelling, it doesn't look like there is. Now you said the left knee is the worst, is it? Can you bend your right? Is that painful?
PAVITT
No.
MAST
Okay. Now when I push here...
PAVITT
I wouldn't say it was painful but it's tender - ahhhh.
MAST
Now where at the top - is it the top?
PAVITT
Yes.
MAST
Not the inside or the outside?
PAVITT
That's quite tender but when you did that on the top it's made me go a bit funny actually.
MAST
Now can you sit up with your legs hanging off the side please? Can you resist me. Is that painful?
PAVITT
Yes.
MAST
Where do you feel that?
PAVITT
There, right there.
MAST
Now do it again in this position, the same ..
PAVITT
Am I pushing against your hand?
MAST
Pushing against - no that's not so much no. And now hold in that position, don't let me ...
PAVITT
Yeah.
MAST
As well a bit?
PAVITT
No not as much as the one when it was bent.
MAST
Okay, now can you lie down on your back again? So there's a combination of things going on. There's a bit of tightness of the lateral rotators or the iliotibial band that runs here but I think it's mostly related to your very tight rectus femoris muslce that has an adverse effect on the mechanics of your - the tracking of your kneecaps, that is a patella femoral tracking problem, they call that. And it's very common in runners and quite often it's just a matter of adjusting the sort of muscle balance around the knee and we picked up a few biomechanical factors earlier on when I had a look at you, you were locking your knees out for example. And exercises to address any of these areas can sort of help to rectify. So basically lengthening whatever is tight - sorry you can sit up - lengthening whatever is tight and strengthening whatever is weak. Then I think on a daily basis to do a programme on your own at home is usually quite effective and you probably need to see your physio, I would say, a number of sessions, maybe three or so to see how the programme is progressing, to see if it's making any differences, to see if maybe things have to be modified - to slightly change - and then take it from there.
EASTON
Hilary Pavitt getting some helpful advice from physio Rob Mast.
BYRNE
I was skiing down in France and basically I was going too fast and I slipped and I just sort of knew I'd damaged my knee straightaway and then tried to get up and I couldn't stand up on it.
EASTON
Daniel Byrne has come to see knee specialist Matt Bartlett at his clinic in Northwick Park Hospital in Harrow. Daniel's damaged his anterior cruciate ligament before - it's a common sporting injury - and he had it repaired by Matt. But now he wants to know what's behind his latest symptoms.
As with many areas of medicine, the patient's story is key to the diagnosis. Matt reckons that 90% of the time he can get an accurate idea of what's going on just from the details of exactly what happened at the time of the injury.
BARTLETT
At the time it happened did you hear a pop or a crack or ...
BYRNE
I heard like a crack sort of sound yeah.
BARTLETT
And how quickly did your knee fill up - when did you notice it was swollen?
BYRNE
Oh that night it was like sort of going black.
BARTLETT
So as soon as you first took your salipets off it was swollen was it?
BYRNE
Mmm yeah.
BARTLETT
Are you saying you had to be brought down on the blood wagon did you?
BYRNE
Yeah I did, on the back of the guy skiing down.
BARTLETT
After that having seen you we diagnosed sort of an ATL rupture - an anterior cruciate ligament injury - and reconstructed that a bit later, how did you get on after that?
BYRNE
I was pretty much fine, I was back playing football - five-a-side football - played a bit of rugby, squash, so I was doing well and then it just - I just slipped down the stairs the other week and it went again.
BARTLETT
So when you fell down the stairs do you think that you twisted your knee again or landed on it awkwardly?
BYRNE
I think I sort of twisted it, I think, it was definitely sort of - my shoe was pretty - didn't have very good grip on it so I think it slipped.
BARTLETT
And did it swell up straightaway or as much this time?
BYRNE
It didn't swell nearly as half as much no.
BARTLETT
Could you walk afterwards?
BYRNE
Not really.
BARTLETT
What do you notice about your knee now after that injury?
BYRNE
I get a bit of pain in it if I've been standing on it for a little while, especially towards the top of my knee. And I just don't feel like it's secure as in how my other knee is. When I stand I stand with all my weight on the other leg really just because I don't want to put too much pressure on that knee.
BARTLETT
Okay, excellent. Do you mind if we have a look at your knee?
And if you could stand up for me first, just so I can have a look at the alignment of your legs. So your knees look nice and straight to me, you've got a bit of swelling around this left knee of yours which is the one that's been affected and there's not too much wasting in the quadriceps and your thigh muscles. Can you push your knees back completely straight for me? And this one doesn't quite go all the way straight does it.
BYRNE
There's a bit of pain in that one as well.
BARTLETT
Generally you're looking at their limb alignment to make sure there's no pre-existing problem with the knee. Then looking at how much wasting there is of the muscles around the knee in particular, that's a very sensitive sign of problems around the knee and tends to happen quite quickly after an injury, within a week or so. Then the next thing that I tend to look at is swelling because if you have swelling in the knee there's obviously a problem in there. Then at the range of motion, you need to make sure that people have got a full range of motion, that there's nothing stopping them coming out into full extension or going up into full flexion. And after that we look at the joint lines, so where the thigh bone and the shin bone meet each other and that's where the menisci live, the fooballer's cartilage, and we palpate along there to see if there's any tenderness. And then right at the end of all of that we look at the ligaments to see whether there's any laxity.
EASTON
And you might then be sort of putting a little bit of stress on them sideways to see whether they're lax?
BARTLETT
Yes and what we're interested in is whether they're lax and whether there's any discomfort when you do that to indicate there's damage to that structure.
EASTON
A lot of people, as with sort of back problems, think that an x-ray's the answer and - I mean I suppose sometimes an x-ray is called for, but in general is it helpful?
BARTLETT
X-rays, particularly in younger people, are generally not terribly helpful, they'll occasionally show a loose body or a fracture but usually you'll have a good idea that that's on the cards before you take the x-ray. They're very insensitive to soft tissue injuries around the knee, so cartilage and ligaments, because x-rays go straight through them, they don't show up.
EASTON
However, something like an MRI scan, a lot of people ask for an MRI scan, you know they come to the GP with a knee injury, but would that be the most helpful thing to do?
BARTLETT
Yes generally, MRIs are very helpful but they have their limitations, they don't show the joint surfaces terribly well and they're not very good for diagnosing problems behind the kneecap themselves. So there's a danger of things that because someone's got a normal MRI scan that they don't have anything wrong with their knee, which clearly isn't the case. About 10-20% of the time things won't show on the MRI that are significant problems with the knee and we can help them with.
We're looking now at the MRI scans of your knee, which were taken a couple of weeks back. Now you see first off - can you see all this white stuff, this is fluid, you're only meant to have a couple of mils of fluid in your knee which you wouldn't normally see on an MRI scan. So this is abnormal, clearly there's something going on in the joint and the joint's not liking it. So then looking through at the rest of the joint. The first thing we're going to do is look at the ACL reconstruction. And that - I can see the fibres there - so that seems - as far as I can tell - that seems to be in good shape. So the next thing we want to look at - and that's what the scan's best at looking at - are your footballers' cartilages - or menisci. Can you see here, we're look at the lateral side first, this is the more normal meniscus and can you see there's a black triangle here which looks fairly uniform and then to the inside of your knee, can you see there's a white line right through it and that's a tear. So this is torn. So what's happened in that recent fall you've torn the back of your medial meniscus - your footballer's cartilage - and the reason that your knee is feeling unstable now is that that is moving in and out of your joint. So essentially what we should do now, if you're happy to go ahead with it, is to do a knee arthroscopy, to look in through the keyhole into your knee, which will let me accurately assess your anterior cruciate ligament reconstruction, make sure that's still in good condition, but primarily to deal with this meniscal tear. From the look of this one, if it is possibly repairable I will repair it, but looking at this one it looks like it's one that we're going to have to take out, the actual tear itself, the bit of meniscus is torn into shreds so it won't be something that I can necessarily fix. You've still got about half of your meniscus left at the back there so that should be enough for your knee to function, I mean you will have a very slight increased risk of arthritis in later life but that shouldn't be too high.
EASTON
Injuries to the menisci are common in sportsmen and women - often caused by a sideways force on a bent knee. So classically a footballer jumping and landing whilst turning at the same time. Or a tennis player swivelling to hit a forehand while her foot stays in the same place on the ground. As well as pain and swelling, people often report a sense of the knee locking or catching, and they may feel that the knee is about to give way.
BARTLETT
This next gentleman's a referee and towards the end of last season he had a sudden onset of pain in his knee - locking and giving way. And I've had a chance to scope him before which demonstrated he had a large segment of his articular cartilage had separated from the inside of the knee - over the medial femoral condyl - the end of the thigh bone - and was floating around inside his knee. We've removed that and trimmed up the unstable cartilage around the defect and done something called micro-fracture to the base that involves making little holes into the bone underlying the cartilage. And the reason to do this is cartilage doesn't have a blood supply so it doesn't normally heal up at all but if you can get a little bit of blood and some clot forming in there then fibroblasts and other cells will invade and actually start to lay down a repair cartilage. It's not as good as articular cartilage but it serves to bear some weight and to actually stick down the edges of the defect. We're re-scoping him because after a number of months he's started to get more pain again, having done very well, got back to full duties as a referee and we're looking to see whether he's got an extension to that area of damage that he had, or possibly some other pathology, such as a tear of one of his footballer's cartilages.
EASTON
The most direct way of finding out what the problem is - and even repairing it - is to look right inside the knee joint using keyhole surgery. Knee arthroscopy is usually carried out under general anaesthetic. The arthroscope itself is about the thickness of a pen and is wired up to a television screen so the surgeon can see clearly what's going on. It's inserted through a tiny cut about a centimetre or so long around your knee.
BARTLETT
So just make a small cut beside the outside of the kneecap. And now we're going to introduce the scope and inflate the knee with normal saline. I can see there's a bit of debris floating around in here. Shouldn't really be anything in there at all. That's the area that we worked on before, so you can see that's quite nicely - there's a bit of a divert out there but it's quite nicely covered by fibrocartilage - that slightly greyer area of cartilage - and the edges of it look nice and stable. So my first concern was that some of that might have got dislodged but that doesn't seem to be the case. Good. There we go - just in that area, although it looked alright at first sight, just in the middle of that fibrocartilage it's just created a tiny tear, there's a little bit of unstable cartilage there, that's nothing particularly to worry about but that would explain why he started to get symptoms, that little bit of torn fibrocartilage is going to be flipping in and out of the inside of the knee and getting caught and that would be enough to give him some symptoms. And they'd be similar ones from the ones he's experiencing, so a little bit of instability but mainly soreness and swelling. Can I have the shaver please? He's also got a tiny little tear right at the back of the footballer's cartilage, on the inside and we'll shave that as well and that should make it much better. That's just shaved out that little bit of unstable cartilage there. This is probably the most difficult bit of the knee to get to, it's right at the back of the medial compartment, it's quite tight, you've got to be absolutely sure that you don't damage the joint surface as you're getting round to it. So what we do is to actually open the joint up to actually put quite a lot of strain on the joint so you get a bit of space. You can see there actually as we get down to it there's actually a much, much bigger tear than we first thought and so this is a new injury he's managed to sustain since the last time I scoped him. And once the meniscus is torn like this the bit that's torn no longer functions. But we try and preserve as much of the rest of it as we possibly can. And the aim is to take out that torn segment. It's the best possible result because it means he's had something that we could treat, well the area we've treated before isn't deteriorating so he should be able to get back to refereeing pretty quickly now.
EASTON
Injury to the menisci may be common in sportsmen and women, but it's the anterior cruciate ligament that wins the prize for the most commonly injured knee ligament in sport. The ACL as it's known is often in the news - for example when footballer Michael Owen damaged his in the 2006 World Cup.
Surgery isn't always essential, but in the case of an active young person keen to get back to physical activity as soon as possible, it often will be. Nina Rangoy damaged hers on the piste.
RANGOY
I was skiing at the time. This was in February. And just a moment's loss of concentration I toppled over and actually the doctor asked me if this was rental skis and it was, so unfortunately they were screwed too tightly and they didn't release. So my knee just basically turned all the way around I think. And something snapped.
BARTLETT
Classically for an ACL injury, that's a weight bearing twisting injury, almost always the knee swells up immediately afterwards and most of the time people will report hearing or feeling a pop or a crack. And if you have those you're more or less sure that the ACL has gone.
RANGOY
I screamed so loud at the time but I don't really know if I heard it. But I knew that something serious was wrong. I kind of felt that I hadn't broken it but I couldn't stand on it. After half an hour, an hour, it started swelling up. I met Dr Bartlett and he told me that he would go in and clear things up to begin with. He listened intently to me and my life, about how active I am in my life. I work as a photographer, I work out, I dance tango and for this I need my knee to be perfect. And so he said we will do a reconstruction of the AC ligament.
BARTLETT
You see one of the tests we do under anaesthesia is something called the pivot shift test and in this we rotate the tibia internally, you can see that as we start to flex the needle there's a little jump and that's called a pivot shift because although we tend to test the ACL by drawing the tibia forward, so an anterior posterior motion, actually what it does is it resists rotation, that's what it's important for, and that's essentially what happens when your knee gives way and deficient ACL is that your tibia, the bottom part of your leg, rotates too far inwards on your femur, on your thigh bone, and then jumps back into position and makes it give way. She's okay if you walks in a straight line, as soon as she tries to make any twisting movement at all her knee gives way and collapses underneath her. The basic principle for reconstructing anterior cruciate ligaments is to harvest some tissue to make into a new ACL. So we have a set of instruments for actually taking two of the hamstring tendons and then fashioning that into a bit of tendon rope. Then you need to drill a hole through the tibia, through the shin bone, up into the knee exactly where the ACL normally comes out of the bone and another one up into the femur, so we have a set of aiming instruments that enable us to do that. And then another set of instruments for actually fixing the ends of the tendon rope in the bone after we've passed it through there. The basics of the surgery aren't terribly difficult but you do need to get everything in exactly the right place, you really do need to be millimetre perfect for placement of the tunnels to make sure that your new ACL works properly.
EASTON
At the Clementine Churchill Hospital in Harrow Matt fashions a new ligament out of Nina's hamstring tendons. The new tendon is carefully prepared with stitches at each end, ready to be pulled through into exactly the right position and then attached to the bones above and below the knee by screws.
BARTLETT
And what we're doing now is first pulling out the lateral wall of the notch, there's actually a notch or space in the middle of the knee between the inside and the outside and that's where the cruciate ligaments sit, like a cross. A bit too far forward it just won't work, it won't be at the right point. Let's have the [indistinct words] then please. The way that we get the drill hole through to exactly the right place we use an aiming device. Five millimetre drill please. And we drill the wire up through the tibia into the old footprint of the ACL, we're now going to over drill that with a drill a sufficient size to pass the graft up. Just checking that that tunnel seems to be pointing about the right direction. Okay so now we've [indistinct words] the lead suture of the graft through the tibial tunnel, through the femoral tunnel and out through the skin on the upper thigh. And we're just going to pull that through, all the way through the knee, see it coming out now of the tibia and then going into the femur and just pulling it hard until it's snugged down nicely, good tight fit in the femoral tunnel. And that essentially is reproducing the normal anatomy of the ACL.
RANGOY
Well now I'm two days after the reconstruction, so still in much pain. Right now I need to basically rest it so that it can give it the time to grow but also try to get some manoeuvrability into the knee. So very, very careful exercises that they've shown me and be on my crutches and in a leg brace. I think that possibly I'll be a little bit scared of skiing but I'm not ruling that out either that I will go back to it but it means more to me to dance. But that I will do - 100% sure.
BARTLETT
Once you have any damage inside your knee if you do have any wear and tear you should really be trying to avoid impact exercise as far as possible, so swimming and the exercise bike are much better exercises than actually running, from the point of view of your knee.
EASTON
And what about things like weight?
BARTLETT
Weight is critically important, particularly for problems behind the kneecap and that's because the lever arms involved mean that the force that goes through the knee is actually very much amplified, so during fairly normal activities you can take three to six times your bodyweight through your patella femoral joint and so small differences in weight make quite a lot of difference to the force that goes through there.
ENDS
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