What procedure should be performed to repair a
ruptured cranial cruciate ligament?
This question has continued
to be the hot topic of the last several ACVS Symposium meetings. The commonly performed cranial cruciate ligament repairs
today are the TPLO (Tibial Plateau Leveling Osteotomy), TTA (Tibial Tuberosity Advancement), and lateral fabellar suture imbrications.
The fibular head transposition has fallen out of favor, as well as the intra-articular repairs that are commonly performed
in humans. A "new" technique is the TightRope repair.
The problem with comparing the different procedures is a lack of controlled clinical trials
and the fact that there isn't a good objective measure to compare the procedures. Typical measures comparing
procedures have included pet owner or surgeon evaluation/happieness with the outcome, goniometery (measuring the joint angles),
force plate evaluation, and kinesiology. Subjectively, we feel these measures to not demonstrate the full potential
of a patient at full performance, like field trial or agility. SUBJECTIVELY, TPLOs and TTAs will consistently get dogs
back to an athletic performance level; lateral sutures will not consistently do this.
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| TPLO repair at Vetcision |
TPLO
There are still few clinical studies
on the Tibial Plateau Leveling Osteotomy (TPLO) procedure. The following recommendations are based upon years of experience with the procedure by Drs. Huss and
Benson. Dr. Huss started performing the TPLO procedure in 1997, and currently has performed thousands of TPLO surgeries.
The TPLO instrumentation and implants are now manufactured
by many companies and have expanded to at least 4 different size bi-radial saw blades (14, 18, 24 & 30 mm radius) and
4 different size plates (2.0, 2.7 3.5 mm & 3.5 mm broad). This range of sizes permits a surgeon the ability
to perform the TPLO procedure on animals ranging in size from approximately 10 pounds to over 250 pounds. The smallest
size TPLO plate (2.0 mm) is equivalent in size to human finger plates. The tiny plates are even more technically
demanding to implant than the already demanding standard (3.5 mm) TPLO.
The TPLO instrumentation and implants are now manufactured by many companies and have expanded
to at least 4 different size bi-radial saw blades (14, 18, 24 & 30 mm radius) and 4 different size plates (2.0,
2.7 3.5 mm & 3.5 mm broad). This range of sizes permits a surgeon the ability to perform the TPLO procedure
on animals ranging in size from approximately 10 pounds to over 250 pounds. The smallest size TPLO plate (2.0 mm) is
equivalent in size to human finger plates. The tiny plates are even more technically demanding to implant than the already
demanding standard (3.5 mm) TPLO.
Each year more and more basic science research has
validated Dr. Slocum's recommendations and research on the TPLO. There is no longer a question as to whether the
procedure works. The big questions now are 1.) Is the the TPLO better than other techniques and 2.)
Which patients benefit from the TPLO procedure. Having performed some of the largest numbers of TPLO procedures, we feel qualified to make
the following recommendations based upon our experience.
- It takes 50-75 TPLO procedures to become proficient with this complex surgery.
- We do not recommend bilateral TPLO repairs at the same surgery.
- TPLO repairs can be performed on any age animal, however,
care must be taken in imature animals with open tibial physis.
- The
TPLO can be used succesfully as a revision surgery in patients that have done poorly with other cruciate repair techniques.
- The TPLO can consistently get athletic dogs back to performance
level.
- The TPLO can be performed on cats and dogs from ~10-15
pounds to over 250 pounds. The size of the bone related to implant size is the determining factor. TPLOs on small
animals should only be performed by surgeons very experienced with the procedure.
TTA
There are even fewer clinical studies on the Tibial Tuberosity
Advancement (TTA) procedure. The procedue was developed in Switzerland after the political fall-out of the TPLO.
The procedure results in changes in force in the stifle that eliminates the need for the cranial cruciate ligament
in a similar manor as the TPLO. The most recent studies are showing similar benefits to the TPLO. The complications
are different than the TPLO, but there are new complications related to this specific procedure. The early reports
were that the procedure was easier to perform that the TPLO, but that doesn't appear to be the case.
The TTA instrumentation and
implants are now manufactured by many companies and have multiple sizes and metallic make-up. There MAY be problems
using this technique on giant breed dogs due to implant size constraints.
All-in-all, the TPLO and TTA are comperable procedures. We have elected to continue
performing just the TPLO procedure since we are intimately familiar with all of the subtle issues involved with this technique.
Lateral Fabellar Suture
For many years,
the lateral fabellar suture had been the gold standard for cranial cruciate ligament repair in small animals. Originally
described by Dr. DeAngelis, and then modified by Dr. Flow, the technique has recently had many different options made available
for the type of suture that can be used. The lateral
fabellar suture is a stabilizing technique that is outside the joint, but under the muscles of the knee. The suture
material is supposed to approximate the pull of the cranial cruciate ligament going from the tibial crest to behind the lateral
fabella of the distal femur(Dr. Flow also put a suture medially). The technique will stabilize the joint, but it can
be very binding. Nearly every technique will losen fairly quickly after surgery. So the patient needs to put scar
tissue down around the joint before the suture losens.
Large diameter
braided suture material was originally used as the suture of choice. There were many complications with infection, bacteria
lodging in the braids of the suture. Large diameter monofilament nylon is now typically used, starting with fishing
line; there are now several sources of nylon specifically made for this procedure. Recently, newer kevlar materials
have been made available as the suture. Metallic crimps have also been developed in place of tying the suture in a knot.
These techniques are relatively easy to perform by family veterinarians and boarded
surgeons. We have found, however, that there are many subtle technical issues that have to be addressed or there will
be problems.
TightRope R
This is a
newly developed extra-capsular suture repair technique for cranial cruciate ligament ruptures. There are not currently
any published reports in the medical journals on this technique. The technique uses newer materials (kevlar suture)
in a novel pre-formed implant. The method can be done through a limited approach to the joint. The end result
is very similar to a fibular head transposition with the suture material going between the tibial crest and the lateral aspect
of the distal tibia.
Since over 50-70%
of patients with ruptured cranial cruciate ligaments also have meniscal injuries, the interior of the joint still needs to
be visualized. This can be done minimally invasively with arthroscopy. Otherwise, the technique could be performed
open.
At Vetcision, we are always looking
to explore better ways of treating our patients. We will keep you informed on this technique as more information becomes
available.
Recommendations based upon patient size
10-35 pound patients
- Patients < 20 pounds may not need surgery if they show significant signs
of improvement within 2 weeks of injury and do not have signs of meniscal injury. Treatment should entail strict cage
rest for a month with NSAIDS. If they are not significantly improved within 2-3 weeks, consider surgery.
- Patients in this weight range will likely do well with any surgical procedure.
We perform the TPLO procedure or lateral fabellar suture stabilization. The only subset of patients we have noted, are
dogs with extremely steep tibial slopes (30+ degree). These dogs have not done well with lateral fabellar sutures.
When revised with TPLO surgery, they have done excellent.
Patients 35-60 pounds
- We offer both TPLO and lateral fabellar suture repair for the dogs
in this weight group.
- If the dog is a performance/working dog, or the owner wants to maximize the
potential for a good functional outcome, we recommend the TPLO.
Patients 60-250+ pounds
- We strongly recommend TPLO repair for the dogs in this weight group. If
for no other reason, studies have demonstrated that dogs with TPLO surgery will start weight bearing on the surgery leg
sooner than with any other repair technique.
- We recommend the TPLO repair exclusively for Rottweilers. The curvature
in this breed's hindlimbs has resulted in an increased incidents of problems with other cruciate repair techniques.
- The giant size dogs have resulted in concern for implant size. Some
surgeons are double plating the 200+ lbs. size dogs. We have not, but we are looking forward to a new larger size plate.
We have had giant breed dogs bend the plate when they have not been properly confined.
The preceding statements are based upon our years
of experience with thousands of TPLO procedures. From our first TPLO (a Bull Mastiff who went on to a CDX obediance
title) our goal was to duplicate Dr. Slocum's technique as precisely as possible. Our hope was to achieve the same success
he had reported. We have been able to do that. Over the years, we have made very slight modifications to the technique
based upon problems or issues we had found with the way our patients had responded.
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| Postop radiograph of a 3.5 mm broad TPLO plate repair |
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| Cruciate Repair Recommendations Postcard |
