Hello and welcome to my course on a 'method of routine diagnostic arthroscopy'.
This is an important subject.
Why? Well, during my years as a knee surgeon, I had a great many patients come to see me
because they were not improved after previous arthroscopic surgery. I was surprised in many
cases to find that their previous surgeon had failed to locate the obvious source of their
symptoms, and I realised that this was because the surgeon had simply not performed a
thorough and systematic examination during the arthroscopy.
For over twenty years now and together with a number of dedicated colleagues, I have been
trying to spread the use of a systematic method to the hundreds of young surgeons who attend
our skills workshops at The Knee Foundation.
This course is aimed at an 'intermediate' level, and may be of interest to both patients, junior
doctors and operating theatre staff.
This is what we are going to cover during the course:

Firstly, I am going to take you through some steps the surgeon needs to take on the
day surgery is decided.

Then we will skip to the short period before surgery, when the patient still has a
chance for last minute interaction with the surgical team.

There will be a brief discussion of the anaesthetic choices, and the preparation of the
patient before the first portal (cut) is made.

I will run over the anatomy with you.

I will explain the limitations of some of the instrumentation an arthroscopic surgeon is
obliged to use.

After this I will explain why it is very important that the surgeon should follow a routine
in fully examining the knee. I will use pictures and videos to illustrate this section.

Then a round-up of some of the conditions most likely to be missed by failing to use a
systematic approach.
Note that, except for a brief overview in the final lesson, we are not going to talk about the
surgical procedures which a surgeon might perform during an arthroscopy - this is the stuff of
more complex courses. The purpose of this current course is to show how important method is
in arthroscopy - and how one can miss the diagnosis by using faulty method.
Informed Consent
Something I want to impress on you is that the surgical routine does not start when the surgeon
puts the knife to the patient's skin. It starts when the surgeon and patient agree that surgery will
be undertaken. Time taken here to explain the procedure to the patient will save much of the
anxiety patients may suffer in the build up to the actual procedure.
In my practice, I have a really useful three-dimensional model of the knee, and I take every
patient through their procedure using this model. It is made by Adam Rouilly and I have found it
over the years to be virtually indestructible. This little model is so useful that I give one to each
of my departing knee fellows (trainees) when they head off back to their own countries to set up
practices there!
The model allows a discussion of various knee cap problems such as tilt and maltracking; it
helps to demonstrate the effect of procedures to improve the mechanics of the knee cap; the
common sites of arthritis can be identified and relevant procedures for arthritis can be
discussed; the cruciate ligaments are easily identified, and the procedures for reconstruction
can be explained. And so on.
I think that this model is much more useful than pictures, as the two-dimensional nature of an
illustration may cause the patient some confusion - whereas the model allows for a much more
sophisticated level of dialogue altogether.
The term 'informed consent' should not mean that the surgeon has informed the patient what
surgery he is going to undertake. It should mean that the patient should be an informed patient.
The patient must understand 
why the arthroscopy is deemed necessary

what the procedure entails

what options the surgeon has should something be found which was not expected by
the investigations prior to surgery

what the patient can expect post op

what rehabilitation entails

what reduction of symptoms is likely as a result of the surgery
Procedures just before the anaesthesia
The period just before the patient receives the anaesthetic is an important time, and again here
a surgeon can miss an important opportunity to 
reassure the patient that it is he who will be doing the procedure, not another doctor
the patient does not know

check that relevant x-rays have arrived, together with the patient notes

confirm the procedure which has been signed for, and that the symptoms are still the
same

make sure the SURGEON HIMSELF, under the watchful eye of the awake patient,
marks the correct knee with a thick surgical marking pen which won't wash off
Picking up that last point, how easy do you think it is to do an arthroscopy on the wrong knee?
Yes. Terrifyingly easy.
Firstly, because the two knees might both look perfectly normal at the time, as there may be no
swelling or external sign of anything wrong with the knee.
The patient is asleep when the surgeon is scrubbing. Also the nurse is draping the knee while
the surgeon scrubs, and the surgeon generally accepts that the nurse won't made a mistake!
But a big black arrow on the bad knee, put there by the surgeon himself before the patient is put
to sleep, ensures that such a disaster does not happen.
I won't go into detail about the anaesthetic, or discuss whether one should have this or that
anaesthetic, but I would just like to tell you about one or two steps which I believe make a great
difference to the patient.
I had the good fortune to work closely with a team of anaesthetists (anaesthesiologists) who
were expert at doing what is known as 'regional blocks'.
A regional block is a nerve block with local anaesthetic, which blocks the nerve in its lower
distribution, in contrast with a local block, which paralyses the nerve structures just around the
injection itself. Some anaesthetists (anaesthesiologists) are good at this and are able to produce
complete loss of sensation in the knee.
For ordinary arthroscopic procedures we used this for some
time, but found that many patients were frustrated that they
could not use their quadriceps muscles for sometimes
several days afterwards.We now use local anaesthetic in the
skin at the sites of the portals before the operation starts and
also leave some local anaesthetic in the joint at the end of
the procedure.
Here you can see the bulge in the skin where the local anaesthetic is being injected.
Don't worry about those pen marks. You will understand what they are when you get to a later
section of the course.
Use of a tourniquet
A tourniquet is an inflateable wrap, which goes around the top of the thigh and gets pumped up
to stop the blood flowing to the limb.
Probably the majority of knee surgeons apply and inflate a tourniquet before commencing the
arthroscopy, and in addition the scrub nurse usually first exsanguinates the leg (squeezes the
blood out using an elastic bandage). This offers the surgeon an advantage in there being
virtually no bleeding during the procedure, but I believe this to be a two-edged sword for the
following reasons:

little blood vessels (even small pumping arteries) may continue to bleed after the
operation, when any swelling is hidden by the bandages and any pain due to the
swelling is attributed to the surgery itself

there is an increased risk of suffering a clot in the leg after surgery if a tourniquet is
used (deep vein thrombosis)
For a routine arthroscopy I do not even apply a tourniquet!
Instead I make a point of controlling bleeding during the arthroscopy by these methods:

I carefully control the inflow and outflow of fluid into the joint using an irrigation pump,
which is ideal. I find this important because any excessive outflow of the irrigation
fluid will cause a drop in the fluid pressure inside the joint and will result in immediate
bleeding. I usually set the irrigation pump pressure at 50 mm Hg (mercury pressure)
and increase this up to 70 if necessary.

The inflow of fluid into the joint needs to be unimpeded. This means that the diameter
of the arthroscope must be large enough to allow a quick flow of fluid if one is going to
pass the fluid into the joint via the arthroscope itself. (We'll discuss the arthroscope
later.) Most arthroscope suppliers these days provide diagnostic and operative
instruments. The operative one allows a sufficiently high flow of fluid into the joint to
maintain pressure whilst doing most arthroscopic procedures. The diagnostic one is
slimmer, but is not adequate if one is going one to use power instrumentation (like a
rotating burr) during any subsequent arthroscopic surgical procedure. The alternative
is to use in inflow cannula - a separate wide-bore needle just for fluid inflow.

I also use adrenaline (epinephrine) in my irrigation fluid in a concentration of 1 part
per two million (1:2 000 000). This constricts the smaller blood vessels (capillaries)
and is effective in reducing capillary bleeding.

If there is any arterial bleeding during the procedure, I control this with diathermy
(cautery), burning the bleeding vessels to seal them.
For beginners in this technique of arthroscopy it may be practical to apply a tourniquet but not
inflate it. It can then be used if necessary. I started this way and graduated to the position of no
tourniquet after a period of three or four years.
OK. This is the end of Part 1. In Part 2 I will discuss the basic instrumentation and its limitations.
In this lesson I will tell you a bit about the instrumentation an arthroscopic surgeon uses and
how the instrumentation imposes limits on what can and cannot be done.
As I mentioned before, I have run skills workshops for many years, and during these workshops
I insist on making the delegates take their equipment apart and reassemble it again several
times over. It is surprising how few, even quite experienced, surgeons are unable to easily do
this, relying on the scrub nurse to do it for them.
Why do I make the trainee surgeons do this?
Well, arthroscopy is a difficult discipline. Think of it. One is
shining a tiny beam of light into the knee through a set of optic
fibres attached to a series of rod lenses that magnify the image
about forty times as well as directing the image at 25 or 30
degrees away from the direction of the scope itself. All of this is
contained within a narrow gauge tubular instrument about 5 mm
in diameter.
This is not like a conventional telescope or pair of binoculars
which look straight ahead. It is like looking through a telescope
at night with a prism on the end that directs both your vision and
a light source 30 degrees to one side. The advantage of this angulation is, of course, the fact
that by rotating the scope you can see a much wider field of vision without moving the telescope
from side to side.
The image is then relayed onto a video screen about two metres away from the surgeon. It is
like a video game. By looking at the screen the surgeon may be looking at the anatomy of the
knee, diverted 30 degrees to one side. When the surgeon rotates the arthroscope (but not the
camera which is attached to the eyepiece of the scope) by 180 degrees, he finds that the field of
vision changes from 30 degrees to the left, to 30 degrees to the right. Without moving the scope
from one side to the other, the surgeon can access a fairly wide field of vision.
The surgeon is on the left, the assistant on the right.
In addition to the technical issues we have already discussed, the surgeon has to operate with
his hands apart, but with the instrument tips close together. A bit like trying to knit while holding
the far ends of the knitting needles instead of the tips!
The surgeon's eyes are on the video screen, not the knee. Not easy!! It takes a lot of practice.
Note the illumination of the knee visible from the outside - it gives an idea of the brightness of
the light beam. Take another look at the surgeon's hands. He is holding an arthroscope in his
left hand and an instrument, probably a 'grasper' in his right hand. Let's look at the former in
more detail ....
The surgeon frequently has to change portals to look at an area from a different angle, and all
this may require that the instruments are removed and disassembled several times, and then
reassembled and reinserted. Dexterity speeds things up.
To make things more complicated, the 'seeing' is done entirely electronically. This means that if
the television screen shows the anatomy of the knee correctly orientated, you know that the
camera (which is attached to the eyepiece of the scope) is the right way up. This is like an
observer standing normally upright and looking at a scene. When the camera is upside down,
which is easily done as it is very small and light, the image on the screen is turned upside down,
like when you look at a view by standing on your head or bending down and looking between
your legs.
Finally, like a conventional telescope the arthroscope has manual focusing which is done by a
rotating mechanism on the video camera.
It goes without saying that if the end of the arthroscope is too close to any structure within the
knee it is difficult for the surgeon to recognise what he is looking at. It is like coming too close to
an object with a telescope - you cannot recognise an object without being far enough away to
see some details of its shape. Two things are important for the surgeon in this respect. Firstly
the knee must be fully distended with saline to allow enough space, and secondly he must pull
the scope back within the available space to clearly visualise (and photograph) the object.
The surgeon, therefore, has to introduce the arthroscope, turn on the irrigation to inflate the
knee with saline, look at the screen, recognise the anatomy and orientate the camera correctly.
He then may need to focus the image and at last by rotating the arthroscope and pulling it back
if necessary he can get a reasonably broad view of the structures within the immediate
surrounding of the end of his arthroscope.
Arthroscopy Setup
The setup for performing a diagnostic arthroscopy consists of:

a fibre-optic arthroscope, with an eyepiece and a system for bending and focusing
the light beam (inserted into the knee)

a light source - with its light beam shining down the arthroscope into the knee

a source of 'irrigation' fluid under pressure - again connected to the arthroscope

a suction machine to remove the irrigation fluid - again connected to the arthroscope

a tiny video camera attached to the eyepiece of the arthroscope

a monitor screen to display the video image

a recording device for storing images and videos during the procedure

a blunt probe, held in the other hand from the arthroscope, for feeling the structures
inside the knee
The arthroscope
The key instrument in an arthroscopy is the arthroscope.
The word 'arthro' means 'joint' and the 'scope' means
'looking' - so this is an instrument for looking into the joint.
We used to do just this - peering down the eyepiece into the
joint - but nowadays the image is relayed via a camera onto
a large
TV-type
screen (monitor).
The stem of the arthroscope is a rigid fibreoptic tube or 'sheath' 5mm wide and the
length of your forearm, in which can be slid a
blunt 'obturator' to close off the tube while it
is being inserted into the knee (both to
protect the joint and prevent the arthroscope
being blocked by anything). At the head end of the arthroscope is located:

the eyepiece, which would normally accommodate a small video camera mounting

a side inlet for the fibre-optic light source

an inlet and outlet for the irrigation fluid, each of which has a little tap for controlling
the fluid flow
The rigid arthroscope, being a straight rigid cylindrical tube with a narrow bore, has certain
limitations:

the image relayed to the TV screen is always a circular one

only a small part of the joint can be seen at any one time

if the surgeons pushes the arthroscope in too close, he may lose his way, and need
to pull it a bit further out to get a wider field of vision

the arthroscope cannot go around corners - although the light beam is bent usually to
30°, the surgeon frequently needs to 'change portals' to get a view around an object
The Blunt Probe
The next vital piece of equipment is the blunt
probe, which is used for feeling and pulling
structure
s within
the knee
joint.
The first
part of any arthroscopy should involve only the arthroscope
and the blunt probe. Too many surgeons fail to fully explore
the joint with the probe before dealing with any abnormality
found inside. On the left, you can see the probe being used
to explore under the meniscus.
On my skills workshops we sometimes have a 'desert island' quiz - "If
you were stuck on a desert island and could only take three
instruments with you to do your arthroscopies, which three would you
take?"
It's a bit of a daft question, as you would also need an anaesthetist,
anaesthetic drugs, electricity etcetera - but it usually results in
enthusiastic discussion, and makes the delegates really look at their
instruments critically.
Needless to say, the blunt probe is always one of the three. The other two are usually a sharp
cutting tool and a toothed 'grasper'. But an arthroscope and blunt probe are all that are needed
to perform a competent diagnostic arthroscopy.
Expanding the knee cavity
The space inside the knee joint is larger than one might expect, due to an extension of the joint
cavity a handsbreadth above and behind the knee cap (the black space where the arrow is
pointing).
During arthroscopy, clear fluid is pumped under pressure into the joint cavity to blow it up and
make more space for the surgeon to see all the internal
structures.
The fluid is led into the knee through the inlet valve on the
arthroscope itself, and the pressure is supplied either by a
pressure pump or by elevating the bag containing this
irrigation fluid on a high drip stand. I talked earlier about the
possibility of a separate inflow cannula to ensure sufficient
fluid pressure, and this is my usual practice.
One of the important roles of the surgeon is to ensure that
sufficient fluid pressure is maintained via the inlet while at
the same time the cloudy fluid is allowed to drain out via the outlet.
One of the key reasons for novice surgeons failing to find problems inside the knee is simply
that they do not know how to keep the joint clean an the fluid under pressure, allowing them to
direct the light source to a clear field of vision. They struggle away in the darkness and can not
only miss things, but they can do damage, too. This is one of the main reasons why I include an
animal model in our skills workshops, to make the surgery as realistic as possible.
This is the end of Part 2. In Part 3 I will show you around the inside of the knee.
The inside of the knee joint is dominated by the two femoral condyles, the shiny rounded ends of
the femur bone (thighbone).
If you imagine that the arthroscope has been
inserted into the antero-lateral portal, it will shine
initially into the gap between the two condyles.
This area is called the 'intercondylar
notch'because it intervenes between the two
femoral condyles . The notch houses the very
important cruciate ligaments. Let's look at this
anatomy in a bit more depth.
The lower end of the femur, including the
rounded femoral condyles, is covered with shiny
white gristle, called hyaline cartilage or articular cartilage. The full extent of this cartilage is only
evident when the knee is bent, although in the image above the artist has taken a bit of artistic
liberty showing it in a straightened knee. During flexion and extension of the knee (bending and
straightening) the condyles are rolled over the flattened tibial plateau, at the top of the tibia.
Integrity of the hyaline cartilage is critical for the smooth functioning of the knee, and damaged
cartilage gives rise to pain and subsequent
arthritis.
Between the two bones, acting as space fillers
and shock absorbers are the flattish wedgeshaped menisci (semilunar cartilages), looking
rather like flattened orange segments.
Composed of a tough spongy material, they
are also critical to smooth joint functioning, cushioning the irregular space between the rounded
condyles of the femur and the flattened tibial plateau.
I'm going to go into the anatomy in more detail, but before I do I want to mention something
about terminology.
The menisci, the wedge-shaped shock absorbers of the knee, are shaped like a half-moon. For
this reason they used to be called 'semi-lunar' cartilages. But confusion arose because doctors
also used this word 'cartilage' to mean the white joint covering (gristle) at the ends of bones. So
doctors dropped 'semi-lunar cartilages' and called the shock absorbers 'menisci'.
That seems straight-forward, but unfortunately the confusion didn't go away, as patients got
used to talking about 'the cartilages' when they were meaning the shock-absorbers.
So if I am talking about the shock absorbers, I will call them 'menisci' - OK?
Menisci
Here is a photo of a real set of menisci taken from a
cadaver for use in a meniscal transpant operation. What do
you think that fleshy stuff is in the middle between the two
menisci? Yes - the cruciate ligaments. They have been
cut off to free the graft from the femur.
The meniscus on the outer aspect of the knee is the lateral meniscus, and that on the inner side
is the medial meniscus. The inner edge is flattened, while the outer edge is thicker. At the front
(anterior) and back (posterior) the pointed ends are called the 'horns' of the meniscus. Hence
each meniscus has an anterior horn and a posterior horn - and both can be difficult to reach during
arthroscopy.
You will see that the two menisci are a bit different in shape. The medial meniscus is more 'Cshaped' while the lateral meniscus is more 'O-shaped'. The C-shaped medial meniscus is fixed
to the joint capsule all around its edge, and there is very little mobility. The O-shaped lateral one,
on the other hand is very mobile.
Which one do you think is more prone to tear? Yes, the medial meniscus. Because it cannot
move much, a shearing force may tear it as it cannot absorb this strain.
Cruciate Ligaments
The cruciate ligaments connect tibia to femur in the middle of the joint
space. The word 'cruciate' means 'crossed' - and the two ligaments cross
over one another. They are very important for the stability of the knee.
The mechanism by which the cruciates maintain optimal stability is
beyond the scope of this course. For our purposes I just want to point out a few key features
when it comes to assessing their integrity:

they actually lie outside the joint cavity, and what you can see from the inside is the
shiny joint lining covering them

this covering may confuse the amateur, as it may give the appearance of the
cruciates being intact, when in fact they may be completely ruptured. Or they may
have pulled off from their bony attachment.
Collateral Ligaments
Those of you with collateral ligament injuries may be wondering why I have not shown the
collateral ligaments. Actually, the collateral ligaments cannot be seen from within the joint, as
they are outside the waterproof capsule of the joint.
On the other hand, the undersurface of the patella bone (kneecap) CAN be seen from within the
joint, but the position of the arthroscope has to be changed to view this properly. In the big
image above if has been peeled to one side to show you what it looks like, but we will be getting
back to this later.
Patella
Now I am going to go back to the bones and talk a bit about
the patella - the kneecap.
Here is an MRI scan, looking at the knee bones from the
side, and where contrast has been reversed so that the
bones are dark. You can recognise the rounded ends of the
femur and the flattened top of the tibia.
The patella (red arrow) is quite peculiar. It is located right in
the middle of the tendon of the quadriceps muscle, the muscle
which forms most of your 'lap'- the tendon being the bit at
the lower end where the muscle attaches to the tibia. From
inside the joint only the undersurface of the patella is visible. The tendon above and below lies
ouside the joint lining and cannot be seen.
The arrow shows you the undersurface of the patella. You can see how it only its undersurface
projects into the joint cavity (white). Any idea what that triangular grey mass is which is
projecting into the knee joint below the patella?
Did you get it? If so, well done. It is the fat pad.
Fat Pad
The fat pad can be the bane of an arthroscopist's life, as it
is bright yellow in colour and can often cover the end of the
arthroscope and obscure the view.
Some years ago, a knee surgeon would have thought little
about cutting away the offending bit, but now it is
recognised, not only that it plays an important protective
role, but also that scarring can be crippling to the patient.
Synovium
Well, we have walked around most of the structures in the knee cavity now, but we have not
talked much about the cavity itself and the important joint lining, or synovium. The synovium is a
glistening membrane which lines the walls of the cavity, and which secretes 'synovial fluid' to
luricate the inside of the joint.
From the point of view of arthroscopy, it is important to know that the joint cavity extends
upwards, a handsbreadth above the patella, into a pocket called the 'suprapatellar pouch' - literally
'the pouch above the patella'. You can see this pocket in these MRI scans (white colour in this
view). Surgeons often fail to fully examine this area, particularly with the arthroscope above the
patella, and problems can be missed.
Actually, on either side of the tibia, too, there are similar depressions called the 'parapatellar
gutters' - literally 'the gutters alongside the patella'. Although these are not so deep as the
suprapatellar pouch, they are important because gravity may allow lttle bits of material to slip
down and hide there, most often 'loose bodies'.
Loose bodies are bits of joint cartilage which have broken off into the joint, but which can then be
nourished by it and grow quite big. Periodically they cause nasty symptoms by getting caught
between the bones, but when the surgeon looks for them they may slip quietly into the
parapatellar gutters to the sides and back - and need to be looked for.
Similarly, at the back of the knee behind the cruciates loose bodies may lurk in a fold of
synovium and be hard to detect.
Synovial Plicae
A plica is a fold of synovium inside the knee cavity,
stretching across the joint. They may exist normally in three
anatomical places:

above the patella (SPP=suprapatellar plica)

along the rounded edge of the femur, to the side
of the patella (MPP=medial patellar plica)

in the notch of the femur below the patella
(IPP=ifrapatellar plica)
When plicae are soft and stretchy they cause little trouble in
the knee. But little episodes of direct trauma (bangs and bumps) may cause them to become
inflamed, to thicken up with scar tissue and interfere with the smooth working of the joint. We'll
look at them again later in the course.
Well, that is a fairly through overview of the anatomy we might see during a routine diagnostic
arthroscopy. I'm going to end the lesson there, I just want to round up by saying that to see all of
the anatomy within the joint, a surgeon must be able to easily change portals, putting the scope
and camera in from different angles. This is because the femoral condyles dominate the field of
view and one has to be able to see below, above and around them. Or things will be missed. I
will try to remind you of the anatomy as we go along to save you having to refer back too often
to this section.
Could you imagine waking up from an arthroscopy with your knee peppered with 'keyholes'
because the surgeon couldn't decide where they should go?
For a 'diagnostic' arthroscopy, usually three portals (keyholes) suffice to examine the knee fully.
For arthroscopic surgery itself, sometimes a fourth may be necessary to deal with some
particularly tricky problem.
What do I mean when I talk of a 'diagnostic arthroscopy'? Well, in the early days of arthroscopy,
when experience was hard to come by and arthroscopic instrumentation was less sophisticated,
orthopaedic surgeons frequently used to look around the joint with the arthroscope to see if they
could figure out the problem inside the knee. They did not actually perform any procedure.
Depending on their findings, they then either opened the knee themself and dealt with the
problem (for example, if there was a simple meniscal tear), or they would terminate the surgery
and refer the patient to someone more skilled (for example, if there was a torn cruciate ligament).
This first 'looking around' became known as a 'diagnostic' arthroscopy.
I am, however, using the term in a different sense. I am referring to the first part of an
arthroscopic procedure, when the surgeon follows a routine of examination EVEN THOUGH HE
SHOULD ALREADY HAVE A GOOD IDEA OF WHAT THE PROBLEM IS AND BE ABLE TO
DEAL WITH IT. There may be more than one thing wrong. He may need a good look around to
plan his second and subsequent portals. I believe there is very little place for using the
arthroscopy as part of a two-stage procedure, and absolutely no place for the beginner to look
around if he is not competent to deal with any problem that he may find.
The issue is that such an inexperienced surgeon is just the one who will miss locating the
problem in the first place. If a surgeon needs experience, the place for it is at the side of a more
experienced surgeon.
Have you ever had an arthroscopy and then been referred to another surgeon to actually carry
out the surgical procedure? This used to be very common. I believe that there is no longer any
place for this. An arthroscopy, even if nothing else is done to the knee, is still a surgical 'insult' to
the knee and the patient runs the risks inherent in any knee surgery - such as infection, deep vein
thrombosis, an anaesthetic complication, reflex sympathetic dystrophy. Why then force the person
into a second procedure? If the surgeon is not competent enough to deal with the pathology
(that is, the problems inside the knee), then he should not be doing the arthroscopy in the first
place.
Why is the first portal so important?
Well, because it is done 'blind' - until the arthroscope, with its fibre-optic light beam and camera,
has been inserted the surgeon can only see the outside of the knee. So if this is badly placed:

the sharp scalpel could slice a bit of cartilage off the condyles

the menisci or cruciate ligaments could be cut accidentally

and last, but not least, if this first portal is poorly placed the whole arthroscopy could
become incredibly difficult.
I teach my students and knee fellows a simple method
of marking the skin prior to the surgery, so that the
patella and safe portal positions are easy to locate,
even after the knee has been inflated with fluid and
the landmarks distorted.
Here you can see the knee is draped with sterile
drapes, and a sterile marking pen is being used to
mark the knee.
The drape has a collection system, as you can see, as a lot of irrigation fluid leaks out during
the surgery, and without this special drape it can go all over the surgeon's legs and onto the
floor!.
I will take you through the method of knee marking in detail.
Marking the portals
Here is how I mark my portals:

With a special surgical marking pen, I mark around the edge of the patella.

Then I mark the position of the tibial tubercle, the bony bump you can feel several
fingersbreadth below the undersurface of the patella.

Straight lines are then drawn on both sides from the edge of the tibial tubercle and
along the edge of the patellar circle, to end two fingersbreadth above the patella.

Horizontal lines are then drawn just below the patellar, and two fingersbreadth above
it.

At the points where the lines cross, I mark my main portals - two circles below the
patella (antero-medial and antero-lateral) (can also be called infero-medial and inferolateral), and two circles above the patella (medial supra-patellar and lateral supraatellar portals).
Very occasionally I might choose to use two other portals - one just below the patella in the
midline, and one to
the side of the
patella.
Here is a view of me
using the rubber
knee model which
we developed for
teaching surgical
skills at the Knee
Foundation.
It is an excellent
teaching aid and is
waterproof, with
superb internal
anatomical detail.
On the left ois a closeup photo of the notch
area taken during
arthroscopy. The
cruciates are just entering the picture at the bottom.
On the model on the right, the circles represent the portals:

supero-lateral

supero-medial

mid-patellar portal of Patel

antero-lateral

mid patellar-tendon

anteromedial
If this is a right knee, have a guess and tell me which portal is the arthroscope being
introduced into? Answer: It is the antero-lateral (infero-lateral portal). I usually use start
with the antero-lateral portal. The lateral side of the knee is the outer side - where you would
slap your thighs.
Now, getting back to the point I made earlier- that the first portal is made blind.
The surgeon needs to appreciate the underlying anatomy so that he does not damage the knee
when inserting the scalpel blade for the first portal.
Also, these simple systems will help to prevent damage to the internal structures:

marking the portals, as we have discussed

filling the joint via a needle with at least 300 millilitres of irrigation fluid before starting
with the surgery

making the incision with the knee straight, in which position the kneecap is up and out
of the way

angling the scalpel toward the femoral notch (we will learn about this in the anatomy
section)

feeling the way with a thin hypodermic needle before following this line with the
scalpel

using one’s index finger as a stop on the scalpel blade to prevent deep
penetration

remembering to put the blunt trocar (oburator) into the stem of the arthroscope before
inserting it
It sounds simple, but I cannot tell you how often I have seen on the soft joint cartilage the tell tale
scrapes of previous blunders by surgeons with careless method.
Identifying the notch
So, just a little recap.
The portals are marked. Some local anaesthetic with adrenaline has been injected into the skin
around the portal. The knee is pre-inflated via a needle attached to a drip containing irrigation
fluid. The antero-lateral portal has been chosen and a thin needle inserted to make sure that the
scalpel will not hit any of the structures inside the knee.
The surgeon takes the scalpel, with his fingers protecting it from going in too deeply, and cuts
the first portal in the direction he now knows to be safe. The scalpel is removed.
The arthroscope, containing a blunt trocar to protect its sharp edge, is inserted in the same
direction into the knee. The blunt trocar is removed
and the light source turned up.
An image appears on the TV screen.
Here again you see the notch between the two
condyles, this time with the cruciate ligament labelled
for you. You are looking from an angle, remember, and looking towards the medial femoral
condyle on the right, while you can see on the left just an edge of the lateral femoral condyle.
The image is round. Why? Because it is being relayed to the camera via the round arthroscope.
We've got to the end of this fourth lesson, now.
I'll just run over a few key points so far:

The skin markings help the surgeon relate the underlying anatomy to what he can
see on the outside, and especially to the portals

The first portal is performed 'blind', and the inside structures can be damaged by
faulty technique here.

I always start with the anterolateral portal, and the arthroscope, with its end bluntened
by the trocar, arrives neatly in the notch between the condyles. The trocar is removed
and the image relayed to the screen.

From now on the rest of the procedure should be done under direct vision.

Poor positioning of the portals will make the surgery a nightmare, and the problem
inside may be missed.

Visibility is maintained by maintaining correct irrigation fluid pressure, by irrigating the
knee should the view become cloudy, and by carefully stopping any bleeding.
In Part 5 I will show you how careful placement of the second portals optimises the positioning
of the instrumentation and allows the surgeon to continue without any problem.
Once the arthroscope is in safely in the knee one is able to continue to work under direct vision.
But surgeons often forget that they can use direct vision to determine exactly where to make
their subsequent portals.
Remember that the arthroscopy started with the arthroscope in the antero-lateral portal, looking
into the notch (blue circle) ... From here, it is possible to see the main features of the anatomy
inside the knee cavity.
Moving the arthroscope over to the medial side (the right on the drawing) the surgeon can see
the rounded end of the femur bone - the femoral condyle, which is normally covered with
glistening white hyaline cartilage (red circle). Below this is the flat upper surface of the tibia bone
- the tibial plateau.
Sandwiched between condyle and tibial plateau is the flattened semi-circular (semi-lunar)
meniscus, with its free edge on the inner aspect.
I'll just move the arthroscope over further to the outer edge of the meniscus. Here you can see
that the meniscus is attached along its outer (lateral) edge to the joint capsule, which looks in
this picture like a silk curtain over to the right.
Remember I mentioned that surgeons often forget that they can use direct vision to determine
exactly where to make their subsequent portals? Well, this part of the capsule, now under direct
vision, is the area where a needle is passed from the outside to locate the right position for the
portal. The needle makes very little damage, so it is OK to try two or three positions before
committing oneself.
I'll show you what I mean.
The light source itself shines from the inside to illuminate the
skin, identifying roughly the position where the needle should
go.
Carefully a thin hypodermic needed can be pushed through
from the skin into the joint, and it is easy to adjust its position to
ensure that the next portal is made without damage to any of
the structures.
The scalpel then follows in the same position as the needle, to make
the second portal under direct vision. Following this I introduce a
small pair of artery forceps or the blunt end of a pair of dissecting scissors. I open these a little
to stretch the portal and make it easier to introduce the probe, and the probe is introduced.
I'm going to show you a video of this sequence now. Don't be put off by the video showing the
instruments being inserted on the opposite side of the knee - it is the priniciple I want to
demonstrate. Then needle has already been inserted to located the right position, and then
removed, but you will see the scalpel following its track, and finally the probe is inserted.
You will then see how the probe is used as a tactile instrument to hunt for damaged or softened
areas in both the meniscus and the bony cartilagenous covering. The screen below may appear
black - click the little arrow to get it to play. There is no sound recorded.
Because the
probe has been
placed under
direct vision, it is
exactly in the
best position to
examine the
meniscus and
joint surfaces.
From here, it is easy to slip the blunt end ender the meniscus, and examine it along its length for
any hidden tears, and to feel the consistency of the joint surfaces.
Now the surgeon really needs to have good tactile skills, because of something we call
'triangulation'.
The left hand - holding the arthroscope scope and camera - locates the area to be examined.
The scope may need to be rotated, so that the light beam, which as I mentioned before is bent
at the end, sweeps around to give a wide viewpoint. The camera may also need to be rotated so
that anatomy is seen on the screen 'the right way up'. A good assistant is a godsend.
Once the area to be examined is located, the left hand needs to hold very still, so that the
surgeon does not become disoriented.
The right hand is at the stage the 'tactile' hand, and the surgeon has to learn to assess the
consistency of the tissue below as he examines them with the probe.
Carefully, each anatomical part is examined, then arthroscope and probe are moved to a new
area, around all the bends and twists of condyle, notch and meniscus.
I am going to start this section by explaining what can happen if the first portal is wrongly
positioned.
If it is placed too close to the patellar tendon, one might lose one's way in the body of the fat
pad, which lies just under the tendon. All the surgeon will see is a bright yellow colour, and not
the shiny white surfaces you are starting to recognise. Removing the obstructing fat can be
traumatic, and the patient can be left with a scarred and painful fat pad, and even the serious
complication of 'infrapatellar contracture syndrome'.
If the first portal is too low, then it will be below the meniscus and tibial plateau, and it will be
difficult to navigate the arthroscope to the other side.
Continue to the next bit to see the kind of mess an amateur finds himself in .... Click the arrow
under the play to start the video. If you cannot get the player to work don't worry - I will also
show some still images to demonstrate the principle. Please note that there is no sound.
This is an example of how NOT to do an arthroscopy. The surgeon is lost in this knee - he is
desperately hunting around to find a landmark he can recognise.
Here are a couple of stills from the video, which just showed a swirling mass of undefinable
tissue -
This could be the fat pad - who knows?
A beginner can spend hours trying to orientate
himself when the image looks like this!
To make sure my students are confident about
the first portal, I turn again to my trusty Adam
Rouilly model to show them where they should
expect the scope to be positioned once they
enter the joint.
Compare the amateur's view with this crisp
image ... Need I say more?
The view should be crystal clear. Failure to see the anatomy clearly may be because 
the arthroscope scope is in the wrong position, and the tip caught up in fat pad or
capsular tissue

the joint has not been properly pre-inflated with irrigation fluid

the fluid pressure is too low

the irrigation fluid is mucky and needs flushing through

some tissue is caught at the end of the
arthroscope
I mentioned before the possibility of using a wide-bore
inflow cannula to ensure optimal pressure using a
pressure pump. Here is a picture of this cannula.
Now I am going to take you through a more expert
diagnostic arthroscopy, step by step. If you cannot view
the videos, there will be an opportunity each time to
see stills. I am going to show first video again. This
time you will appreciate how clear the image is. Note:

how the surgeon explores both above and below the meniscus

how he is feeling the integrity of meniscal and bony surfaces with the tip and the side
of the probe

how he pulls on the outer edge of the meniscus

how he checks the posterior horn of the meniscus. The anterior horn is more difficult
to see from the original antero-lateral portal, and he needs to change portals, as I will
discuss later
Click the video arrow button to start the video... See how after fully examining the meniscus and
joint surfaces on the medial side, the surgeon swings the probe over into the notch to explore
the cruciate ligaments ...
On the right are still images for those of you
unable to play the video.
I have labelled the important landmarks for
you. The rounded white condyles are
important in orientating yourself. To the right
the tibial plateau is being examined. The
hyaline cartilage covering the bone here looks
a bit thin and pink coloured.
Here the probe has located a damaged area of
the tibial plateau.
In this next video the probe is in the notch. The surgeon is trying to examine the cruciate
ligaments. At first glance looks as if they are fine. But when the surgeon tries to pull on them
with the probe, he discovers that what he is seeing is not the cruciates at all - but a filmy infrapatellar plica masquerading as a cruciate! Such plicae are not always present. After 'hoovering'
away the plica, the real cruciate is revealed below. Now pulling on it tests its true integrity.
From this position, still with the scope in the original portal, the surgeon can slip the probe round
the back of the cruciate and test the posterior horn of the lateral meniscus, the body of the
meniscus and the joint surfaces as before.
I'll show you the stills again here. To the
novice, the cruciate seems to be filling the
notch, and looks normal. The probe, however,
can slip easily into the filmy material - and the
experienced surgeon identifies this as an
infrapatellar plica covering the real cruciate
ligaments.
A high speed rotating instrument is used to
quickly cut and suck away the filmy plica, with
the teeth pointing upwards to avoid harming
the underlying cruciates.
Now the surgeon can confidently test the
integrity of the cruciates, by pulling on them
firmly.
Now a surgeon, and especially an arthroscopic surgeon, has to train himself to be
ambidextrous.
If he finds it hard to see a part of anatomy, he needs to remove the instruments and swop their
positions around, coming in from the other side, or maybe even a third or fourth portal. This can
cause the novice a problem, as it is often hard to locate the portal again, as the tissues are in
layers and the gap can appear invisible. I teach the use of what I call a 'switching stick', to allow
a quick and easy changeover, without losing the portal. Failure to do this can result in long
delays in the operating room, and the surgeon may need to start all over making the portal
again!
And while I
am talking
about
problems, I
just want to
mention
again the
issue of
bleeding. It
is quite
easy to see when you have cut a bleeder. I make sure than any bleeders are cauterised.
Keyword (tags):
arthroscopy
infrapatellar plica
As we continue on this arthroscopy voyage together, I just want to touch upon the subject of
plicae. We mentioned them in the anatomy section as folds of joint lining left over from the
embryonic stage of knee development and I will go into more detail in the next part of the
course. For the moment I want to show you three illustrations to keep the topic started.
The commonest problematic plica is the medial plica. In the left image it is seen draped like a
curtain over the medial condyle, attaching at the bottom to the fat pad, at the top to the wall of
the supra-patellar pouch and on the outer aspect to the rest of the joint lining. This last is not
appreciated easily from an illustration.
In the next two images, you will see how the plicae can get irritated or damaged when the knee
is bent, particularly if they have recently taken a bump and become swollen or thickened.
I'm not going to go into any further details about plicae, as this is not the purpose of this
course. The issue is that many knee surgeons dismiss them as unimportant, because from
below it is hard to appreciate the mechanism by which they cause symptoms, simply because
the scope is in the wrong position and you should be able to appreciate this from the
illustrations. I will show you in Part 8 how I examine them.
But getting back now to my system of examination ...
Before swinging the arthroscope up and around the
condyles, noting any plicae as we go, the 'gutters' to the
side of the joint cavity must be examined. These are often
forgotten by the novice, but are notorious for hiding 'loose
bodies' - bits of joint surface which have detached and
which grow bigger in the joint cavity.
After examining the lateral gutters, the arthroscope is
brought up and around the condyle to view the trochlea
and the undersurface of the patella - the region known as
the patello-femoral joint. Again, this will be dealt with in the next lesson, when we view this
region from a new portal.
We are nearly finished this lesson now. I'll just show you a video of this region being examined
with the probe. You will notice some abnormal softness of the joint surfaces.
The red
circle in the
left hand
image
explains
where the
probe is
probing. Just
ignore the
arthroscope
in the picture - I need to edit the image. In the right
image the probe has reached underneath the patella,
where the cartilage is not normal. The probe is able to
make a dimple (this softening is called
'chondromalacia'). You can see the fluid inlet in the distance.
This is the end of this lesson now.