Clean Run - October 2015 - 30

joint conformation-no one knows for
sure. As discussed previously, this instability can still cause lack of congruent
movement, abnormal stress points in
joint cartilage, and compensation adaptation of tissue, posture, and movement from the micro to the total body.
Although it is treated as insignificant by
many surgeons, over time this instability evidently does matter judging by the
severe arthritic changes that develop
in most TPLO joints.
No one is really sure how many TPLO
dogs develop severe arthritic side effects versus those that undergo other
repairs versus those that are treated
with conservative management; there
is little research looking at these patients longer than 12 months, although
several studies have reported a 25-38%
overall post-TPLO surgery complication
rate. What little long-term or comparative research that has been done to
evaluate the TPLO since Dr. Slocum's
death have shown:
* There were no significant differences found in limb function between
TPLO and extracapsular repair two
years after surgery.
* After initial improvement, stifle joint
range of motion started to decrease.
* Joint range of motion and thigh
circumference in surgically treated
limbs remained significantly decreased relative to contralateral
limbs 1-5 years after surgery.
* 30% of treated dogs were found
to have signs of chronic pain when
long-term outcome was evaluated
at a mean of 2.7 years after surgery.

#4: Collateral Damage
Fourth, there can be collateral damage
from TPLO hardware, both in the bone
and in other tissue. Anytime an implant
is placed in bone that has been traumatized, the window is open to bone
infections (resistant staph infections
are starting to be a problem in the veterinary surgical world just as in the human one). Also, screws can back out,
animals can react to the metal implants
and the placement of improper length
screws can interfere with interosseous
tissues, leading to chronic pain and
movement restriction.
Following is a common problem we see
in TPLO dogs at my practice: Figure 4
shows an x-ray of a pitbull-type dog
that had already a TPLO surgery on
each hind leg. He now presented with
lameness and pain in the right hind leg.
The left CrCL (on the left of the x-ray
image) was repaired first with proper
length screws. The right CrCL (right side
of x-ray image) ruptured 4 months after the first one and was repaired by the
same surgeon using longer screws this
time (perhaps other screws were not
available?). The dog started acting significantly lame on the right leg (the second repair) about 18-24 months years
after the surgery and showed significant pain when the muscles between
the tibia and fibula were palpated (cranial tibial muscle). You can see in the xray that the longer screws used in the
second repair penetrated through the
5

X-ray of dog with bilaterally repaired cruciate
tears using different lengths of screws;
the left leg is on the left and the right leg
is on the right.
30

If I were faced with these numbers when
looking at a surgical procedure to repair
my own ACL, I might have serious second thoughts about whether it would
be worth the effort, pain, and expense.

bone of the lateral tibia and into the
interosseous space between tibia and
fibula. It is easy to let your eye see the
dark between the two bones as empty
space, but it is actually packed with
multiple muscles, major blood vessels
and several nerves.
In these two ultrasound images, the
difference between the right and left
legs is significant. The screws poking through the nerve-rich periosteal
bone covering can be seen as can the
scarring that they have caused. Bone,
metal, and dense scar tissue produce
a white "hypersound" or "hyperechoic"
signal because they bounce more of
the sound waves back to the ultrasound probe; muscle and fluid conduct
sound away instead of returning it, so
they produce a black or lighter grey hypoechoic image. See Figures 5 and 6.
I just had a similar thing happen to me
with a fractured ankle repair where a
bone screw penetrated the bone too
far on the opposite side of its placement. I can tell you that the irritation
and discomfort can be significant and
should not be minimized by a surgeon.
It took months to resolve the feeling of
pulling and tightness (and pain) of that
scar tissue. These are all problems that
can affect quality of life post-TPLO.

Why We Can Do Better!
So, after all that, can we conclude that
the TPLO is worthless? The answer is
definitely no. The procedure has helped
numerous dogs return to function. Do I
recommend it? Sometimes; if a dog has
had one side done and then ruptures
the other, I recommend it (especially if
it can be done by the same surgeon) in
6

Left leg showing a smooth, white tibial
surface and normal muscle striations
with some scar tissue.

Right leg showing marked unevenness from the screws
poking through the tibial bone surface and significant
loss of muscle structure due to the formation of scar tissue
against the bone.
Clean Run | October 15

Clean Run - October 2015

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