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This article represents the personal opinion of Alistair Marks MRCVS at the
time of writing. It is offered, as information as might be presented in the
consulting room and not a scientific document and no liability for acting on any
information written here is accepted. It is not intended to replace your
consultation with your veterinary surgeon but it may help in discussing the
various options available to you should your pet suffer a cruciate injury.
Anatomy and function
The stifle joint is equivalent to the knee, in ourselves. It is a joint
between the femur (thigh bone) and the tibia (shin bone). Although primarily
functioning as a hinge, it is much more complex in that as well as flexing and
extension, the stifle can rotate (twist) as well, to a degree.
Key to the functioning of the stifle are the ligaments. The big ones on the
inside and outside are called the collateral ligaments and stop the stifle
hinging to the side. The pair of cruciate ligaments are arranged in a crossed
over pattern (crucifix). Their job is to prevent forward and backwards movement
in the tibia in the direction of the arrows. This means as the stifle flexes and
extends the surfaces glide over each other and a healthy stifle will flex and
extend millions of times in a lifetime, without wearing out. It is the cranial
or anterior cruciate which is the most commonly injured and whose job is to stop
the tibia sliding forward in relation to the femur.
The final significant part of the anatomy of the stifle is the menisci or
"cartilages". There are two in each stifle, both kidney bean shaped and lying to
the inside and outside of the middle axis of the joint. They act as a shock
absorber and also help restrict the forward and back movement of the tibia but
are only able to do this in combination with the cruciates.
Why do they fail?
We see many presentations of cruciate failure but broadly
speaking they can be truly traumatic where an extreme of force is applied to a
relatively normal ligament. Such an event might include a road accident, or jumping
for a Frisbee, or running along and putting the foot down a hole or jumping a
fence and getting a foot caught. Other patients we see have a
degenerating cruciate that finally fails when subjected to modest or even normal
stresses. This can happen to both older dogs but also younger dogs, the younger
ones often having with poor hips as well. Unfortunately dogs with degenerating
cruciates often end up with both stifles affected. What will I see?
In the truly traumatic cases, your cat or dog will be usually
completely lame and obviously sore. With the degenerative ones
the dogs (as it tends to be dogs who present in this way) are lame but the
lameness can be variable from complete to light.
How is it diagnosed?
A thorough examination and history taking will often
establish that the problem lies within the stifle. Being able to feel or see the abnormal forward and back movement of the tibia would confirm the
diagnosis. However often the injury is quite subtle and
sometimes only a partial tear is present. Also sometimes dogs are so tense that
it is impossible to demonstrate the abnormal movement. The
next stage is to repeat the examination under sedation and also take some
x-rays. This means the limb is relaxed and often the abnormal movement can
be generated whereas it was not felt in the consulting room. Some dogs have such
a small tear that no abnormal movement can be produced but they are,
unfortunately on a journey towards failure. Although ligaments
are not seen in an x-ray, the picture can show up early signs of change in the
joint such as extra fluid in the joint or the appearance of little spicules of
new bone. What is the consequence of cruciate failure?
Once the cruciate is damaged enough to allow abnormal
movement in the joint the joint starts along a journey of arthritis. The journey
is unfortunately only one way and the joint will continue to deteriorate
throughout the animal's life. However there is much that can be done to reduce
the severity of the arthritis and therefore the impact of the injury
What should be done?
Some cats and very small (toy) dogs will, sometimes, do well
enough, given several weeks of cage rest. This is a strict regime, not to be
undertaken lightly. The pet is confined in a cage at home and in the
case of a dog lifted outside for toileting and then lifted back into the cage.
The idea of this treatment is that the other structure in the joint will "beef up"
to allow the joint to function without the cruciate ligament. Results tend to be
variable but it can provide an economical outcome, in some cases.
Small and medium patients can be treated by a surgical stabilisation of the
joint. There have been many dozen techniques described in the literature over the years. At Oak
Tree Vet Centre, a fascial graft is the method used. Larger
dogs, Labradors and above can do well with a fascial graft but their recovery is
slower and the graft is vulnerable to snapping. For these patients a TTO or
triple tibial osteotomy is performed, in preference. Fascial
graft repair.
A fascial graft or "over the top" repair is a soft tissue
repair where a strip of the dog's (or cat's) own tissue is harvested from the fibrous
tissue covering the muscle of the thigh and placed within the joint to mimic the
path and function of the failed ligament. A long incision is
made along the outside front centre line of the leg and a strip of fibrous
tissue detached from the top of the leg, near the hip and carefully peeled down
the leg to where the patellar (kneecap) ligament goes into the tibia. The stifle
joint is then opened and the diseased ligament cut away using a fine blade. The
body will remove the redundant ligament in time but it is thought that removing
as much of the diseased tissue as possible will allow a more speedy resolution
of the inflammation. Then, the cartilages are carefully inspected for damage and
any damaged portions removed. The graft is passed between the
condyles (knuckles) of the femur and round the back of and over the top of the
outside of two little bones called fabellae. The graft is then sutured down to
the outside of the femur and the end taken down and sutured to its starting point
for a more robust repair.
 The joint is then flushed of clots and
debris with sterile saline and then flushed with local anaesthetic which
promotes a more comfortable recover. The joint and the fascia
is then closed. The harvesting of the graft means that after closing the gap the fascia is pulled tight.
This adds to the stabilisation of the joint provided by the graft.
The remaining tissues are sutured, routinely.
Bone altering procedures.
In large dogs, the speed of recovery and the reliability of
the soft tissue repairs is more of a concern due to the larger forces operating
in the joint and also on occasions due to anatomical irregularities. In recent
years three procedures have evolved, all of which alter the angle of the top of
the tibia in relation to the pull of the thigh muscles through the patellar
tendon. The diagram below shows the pull of the quadriceps
(thigh) muscle through the patella down ro the attachment of the patellar
ligament onto the tibia.
The other line shows the angle of the tibial plateau (bearing
surface) The lines are not at right angles and as a
consequence there is a force trying to cause the tibia to slide forward under
load (animal stepping) and slid backwards when the weight comes off. The
function of the cruciate ligament is to resist these forces.
With no functioning cranial cruciate ligament, the tibia therefore tends to slide forward
and the femur back on each other in the direction of the arrows when the dog
bears weight and the opposite when not bearing weight. This accelerates the wear on the joint and the arthritis
progresses. What can be done?
If the top of the tibia or tibial plateau, as it is called, can be levelled,
so that it is perpendicular (at 90 degrees) from the pull of the patellar
ligament the pull of that ligament during weight bearing will minimise the
forward and back ward shift of the bones. How is this achieved.?
Currently there are three main methods The first and most common is the
TPLO or
tibial plateau levelling osteotomy, (osteotomy means cutting of a bone). In this
technique, a circular cut is made in the top of the tibia and the little piece
of bone rotated and held in place with a plate. A special saw and blade is required for
this technique and the repair is perhaps initially less stable with a loose
circular section. Also the circular blade may have a tendency to become hotter
than a straight blade, risking burning the cut surfaces of the bone and delaying
the healing. TPLO
The alternative way of altering the angle is to alter the
angle of the patellar ligament. This is called the TTA
or Tibial Tuberosity Advancement. Here a straight cut is made in the tibia and
the front section (darker) pushed forward and held in place by a sophisticated
and expensive! titanium plate. The big advantage of making only this cut is that
the long (load bearing) axis of the bone is not cut and that should improve
patient recovery. However the disadvantage, is that the repair can be vulnerable
to catastrophic failure.
TTA
The third
angle altering technique is the triple tibial osteotomy or TTO. A surgeon in New Zealand,
Warrick Bruce, came up with a combination of the two techniques above, involving
straight cuts (less heat) and doing a little bit of both angle changing methods.
He and a peripatetic surgeon in Australia had
repaired over 800 stifles with their technique before coming over to the UK to
train and share their knowledge with UK veterinary surgeons. They have developed
a special set of instruments to be used alongside the standard orthopaedic saw
to remove much of the guesswork and feel needed to manage, successfully, the TPLO
procedure. It involved making a cut as in the TTA above and then
removing a little wedge in the main bone shaft. Closing the wedge drops the
front of the tibial plateau like the TPLO and at the same time pushes the
tuberosity forward like the TTA. None of the cuts are completely through the
bone and when the plate is applied it holds together a straight and inherently
stable join. TTO
TTO
Up until very recently At Oak Tree Vet Centre, we had decided
to offer the TTO as our preferred method of cruciate repair in large dogs.
These bone altering procedures
involve a significant investment in training and equipment. Here is our
operating trolley, ready to start a TTO.
What we do now.
A new material has recently come into veterinary use. It is a
titanium sponge called Orthofoam that allows bone to grow into it creating a
secure and permanent bond with the bone.
Cut into precisely measured wedges it is the ideal companion
for the TTA procedure filling the wedge, completely and providing a very strong
resistance to the wedge space collapsing. It is held in with a single pin and
figure of eight wires. In recognition of the first human surgeon Dr. Maquet who
first provided a similar procedure for his patients in the 70's the procedure is
the Orthofoam MMP TTA (Modified Maquet Procedure, Tibial Tuberosity Advancement.
Orthofoam MMP TTA
What happens on the day of the
operation.
Whether your pet is having a fascial graft or Orthofoam MMP TTA, he or she would be
admitted early in the morning and settled into one of our day kennels in the
prep room. Prior to the administration of the anaesthetic, we shall weigh and
re-examine your pet and if it has not been done already, take a pre anaesthetic
blood sample. The practice has a modern blood analyser for this purpose and
results are available within 15 minutes, allowing any adjustments to be made in
the anaesthetic protocol.
As both procedures are significant operations we provide intravenous fluid
support (a drip) for all our cruciate patients.
It is the routine at Oak Tree Veterinary Centre that patients receive not
only a sedative to allay any fear but two analgesics (painkillers) as their
premedication before general anaesthesia.
Following induction of anaesthesia, all patients are intubated to protect
their airway and maintained via a modern gas anaesthetic system featuring
sevoflurane, the latest and considered the best anaesthetic gas. At this time an
intravenous antibiotic is given to reduce the risk of infection.
All anaesthetised patients are monitored throughout, by the theatre nurse
under the constant supervision of the operating surgeon. The leg is shaved and
vacuumed to remove all hair. The skin is then washed and disinfected by a three
stage cleansing program
All patients have, of course, their own set of operating drapes and
instruments. We have surgical power tools from human surgery that are autoclaved
along with the large selection of instruments that are needed for these
procedures.
The patient is draped with large cloths and the foot recovered in a sterile
bandage. Finally a clear operating sheet is applied to the skin of the leg which
means practically all of the skin is covered.
We set up surgical suction and surgical diathermy.
The procedure begins with both the primary veterinary surgeon and a scrubbed
assistant, whilst a veterinary nurse monitors the anaesthetic and a fourth
person is available to meet the surgeon's equipment needs throughout the
operation.
At the end of the procedure, before leaving the theatre, the wound is
cleansed with sterile saline, dried and a spray bandage applied. On top of this
a sterile bandage like a giant elastoplast is stuck.
We don't use a bandage so that the patient has mobility right from
immediately post op.
For dogs undergoing a an Orthofoam MMP TTA, a post op x-ray is done to check that the
Orthofoam wedge, pins and wires are still correctly placed.
All patients receive post operative pain relief for as long as is required
for them to recover from surgery.
We now offer therapeutic laser therapy at the time of surgery to reduce port
operative discomfort and swelling. We are the first in Scotland and one of the
first few practices, in the UK to have a Class IV laser.
Post operative care
On collecting your pet, both the surgeon and a veterinary nurse will go
through what has been found and done and give written instruction to help you
manage the initial recovery.
We like to check all of our cruciate patients after three days. With both methods, we remove the stitches after
10 days.
With the fascial graft, it is imperative that the stifle is carefully
looked after Minimal, toilet exercise on a lead and no jumping, stairs or
playing for the first four weeks and then a gradual increase in lead exercise
With the Orthofoam MMP TTA, the fog is allowed a few minutes lead walking
several times a day right from day one, a big advantage for boisterous large
breeds. At four weeks post op, we take a check x-ray to ensure everything is
correct.
At this time, we hope to start active rehabilitation. We believe, in the case
of medium and larger dogs, the best rehabilitation is hydrotherapy and the
equipment of choice is the water treadmill. Twice a week sessions, wading slowly
in deep warm water builds up the muscles in the leg, with minimal danger to the
healing joint. Our sister business petphysio.co.uk, which is and on site, here,
conducts the hydrotherapy, ideally twice a week for 6 weeks (12 sessions).
Simultaneous with the hydrotherapy sessions we like to give a course of four,
once a week, injections of a drug designed to curb the inflammation in the
healing joint.
Some of our cruciate patients have continued to attend regularly for
hydrotherapy, as the dogs have enjoyed themselves so much and that it keeps them
in peak condition.
What about the arthritis?
Unfortunately, the moment the cruciate begins to fail in the case of
degeneration or snaps in the case of trauma there is an inflammatory process
leading to the establishment of arthritis. Arthritis is a progressive disorder
but there are many things that can and should be done to slow down the
progression of the arthritis and minimise it's impact of your pet's quality of
life. The surgery is a significant part but there are four cornerstones to
managing the stifle arthritis or indeed any arthritis.
They are
1) Weight control. Being too heavy does not cause arthritis but if your dog
is to heavy and has arthritis or an injury it progresses much more quickly,
the disability is then magnified leading to the possibility of failure in another
leg.
2) Regular and reasonable exercise. Too much or strenuous activity is just as
bad as not enough. If your dog has arthritis you need to look at your
pet's routine, curb the excesses and make time for some gentle exercise every
day. Do not fall into the Ben Nevis syndrome where your dog bags some Munroes
at the weekend and is wiped out for most of the week, recovering just in time to
give his joints another battering, next weekend.
3) Supplements, in the form of additions to normal diet or the shift to a
"joint" diet is a major part of looking after the joints, next week, next
month and next year.
4) Drugs, surprising, are the last item, not the first. There is undoubtedly
a role for drugs to manage the stiffness and inflammation especially early on
after surgery or when there is a flare up. However there may be long periods when
daily administration of drugs is not necessary.
At Oak Tree Veterinary Centre, we are well placed to guide you though making
the most appropriate choices for your pet.
Why come to Oak Tree Vet Centre?
Alistair Marks, the proprietor of Oak Tree Vet Centre, is not a
registered specialist but is a practitioner of more than 28 years' experience and has
studied for and gained two formal post graduate certificates, one in small
animal orthopaedics, the other in veterinary radiology, as well as attending
numerous educational meetings both in the UK and abroad. He has brought
together what he feels is a worthwhile and comprehensive total case service from
diagnosis to managing your pet through the surgery, rehabilitation and then
maintaining mobility as far as and as long as possible, all here at the
practice. He is ably assisted by a team of four Registered Veterinary Nurses who are very
active in the provision of care, at all stages. We are careful to provide the
best experience during the perioperative period for your pet and enthusiastic
assistance during rehabilitation, which most dogs thoroughly enjoy.
We are content to make a direct claim to most of the significant insurance
companies if we have sight of the original policy documents prior to the
commencement of treatment. Please read our practice brochure and speak to us to learn more about this aspect of our service.
Oak Tree Veterinary Centre.
539, Queensferry Road, Edinburgh. EH4 7QE
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