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Ron Hines DVM PhD.......... An important message from Dr. Hines Lots of my articles are plagiarized and altered on the web to market products and services. There are never ads running or anything for sale with my real articles - other than my time. Try to stay with the ones that begin with http://www.2ndchance.info/ in the URL box or find all my articles at ACC.htm. The Anterior Cruciate Ligament (ACL) and the Cranial Cruciate Ligament (CCL) are the same thing. Our knee is our pet's stifle. Physicians describe the ligament as "anterior" because it is toward our front. Veterinarians describe it as "cranial" because it is toward the pet's head. What Are The Cruciate Ligaments And What Happened To Them In My Dog ? Your dog’s knee is also called its stifle. The two most common problems that involve this joint are torn or stretched cruciate ligaments and dislocating kneecaps, which you can read about in a separate article here . The condition of your pet's cruciate ligaments and its patella (knee caps) always need to be evaluated together (ref). Your pet's stifle is the joint that bridges the upper and lower leg bones, the femur and tibia (click "full size" here or above). Your pet's stifle is an amazingly complex joint. To add stability to the joint, Nature has provided some very strong ligaments. Two of these are attached in a crosswise fashion, hence the names, anterior and posterior cruciates or “cross” ligaments. These ligaments act together with two outer bands of fibrous ligament, the lateral collateral ligaments, and the kneecap to maintain your pet's knee stability through a wide range of motion. A small group of dogs suffer torn cruciates as a true sports injury. These are dogs that test the physical limits of their bodies through over-exertion, agility trials, roughhousing, dock jumping, and Frisbee catching. But veterinarians see cruciate ligament damage much more frequently in overweight, neutered, middle-aged dogs. Veterinarians used to think of cruciate tears as a relatively simple and straightforward problem - the dog made a sudden incorrect move that tore the ligament. But recent research has shown that cruciate problems are anything but simple and straightforward in their cause and treatment.
Research has shown that dogs over 4 years old that are spayed or neutered are considerably more likely to suffer cruciate tears than dogs that remain sexually intact. We used to think that cruciate problem appeared suddenly – after a sudden twisting movement or due to jumping up or out of an elevated location. But we now know that this problem has usually been brewing for some time. There is even some evidence that these ligaments may tear after your pet's joint becomes inflamed (lymphoplasmacytic synovitis) - rather than becoming inflamed because of a torn ligament as we had once supposed. Whatever the cause or causes, something more than a simple accident is usually occurring because it is common for the pet's second knee to go out sometime after the first. Another group of dogs that suffer from this disease are those receiving corticosteroid medications for long periods. It is uncertain if these pets develop the problem because they gain weight or because corticosteroids decrease ligamental strength. A similar over-abundance of corticosteroid occurs if your pet develops Cushing's disease.
How Is A Cruciate Problem Diagnosed In My Pet? Examination of a painful stifle (knee) in your pet is best done under anesthesia or heavy sedation. Besides being painful, the muscles of your pet's joint will probably be in spasm, making diagnosis difficult or impossible in un anaesthetized pets. After relaxing the pet, I place one hand on the thigh to immobilize the femur and with my other hand I attempt to move the tibia anteriorly and posteriorly as the white arrow indicates in the diagram. A normal joint will not move in these directions because intact cruciate ligaments prevent it. Only in knees where the cruciate ligaments have snapped or stretched is this forward and backwards motion possible. We call this motion the “anterior drawer” effect. In old injuries to the knee, scarring may prevent some of this characteristic motion, but not the pain. In old injuries, the lateral collateral ligaments that stabilize the knee may be stretched and loose as well. In most cases it is the anterior, rather than posterior cruciate ligament that has torn. When there is any question in my mind as to the diagnosis, I compare the looseness of the affected joint with the normal one. Particularly when the tear is old, the affected knee may pop and click when it is manipulated. On occasion, these joints are puffy with excess fluid. Specialized veterinary centers confirm cruciate tears in a more sophisticated way. When the dog's size allows, an arthroscope can be inserted into the joint to actually see if the cruciate ligament is torn or if the meniscal cartilage is damaged. X-rays will not detect the damaged ligaments in your pet when they occur, but they will pick up later arthritic changes as they develop in the unstable joint. It is also quite common for cruciate ligament damage to be misdiagnosed as a hip dysplasia problem and some dogs actually do have both hip and knee problems simultaneously. In the rare instances where both legs are affected simultaneously, the diagnosis can be mistaken for a spinal nerve injury. What Treatment Would Be Best For My Pet ? Veterinarians treat pets with cruciate ligament tears medically or surgically. Conservative Medical Treatment If your dog's optimum weighs is 55 pounds or less, medical treatment is probably the best choice. Most of these lighter pets will improve with a conservative treatment of rest, restriction of strenuous exercise, hydrotherapy and anti-inflammatory medications. More than two thirds of the dogs that weight under thirty pounds will be nearly normal in six months. Some veterinary hospitals have specialized tanks and whirlpools for hydrotherapy or will refer you to a center that does this. Stretch/range-of-motion exercises also seem to be quite helpful. Others practice treatment with less documented benefits such as cryotherapy, laser therapy and neuromuscular electrical stimulation – treatments commonly used in sports and rehabilitative human medicine. Orthotic knee braces are also an option for residual pain, rehabilitation, as an alternative to surgery or to aid in post surgical recovery. When knee braces have good design and fits well, they can be a great help for dogs with knee problems - with or without surgery. However, they only work well when they fit well and when your dog does not destroy them in an attempt to get them off. Some dogs accept them readily and think nothing more about them. Others plot throughout the day on ways to get them off. Tight fitting braces cut off circulation and irritate the skin. Loose fitting braces fall off and do not give adequate support to the knee. It is just like wearing a set of shoes that are not your exact size or somebody else's eyeglasses. I am dubious about services that plan to mail your dog a brace based on x-rays, size or breed. The results will be like ordering a new suit without having the tailor measure you in person. Maybe you will be lucky and it will fit; but maybe you won't. Ideally, bring your dog to the orthotic specialist to be fitted. If that can not be done, have a cast prepared of your dogs leg and have the specialist use that as a mannequin to construct the brace. Be sure their re-fit, refund and return policy is given to you in writing before your purchase. Be sure they are not gong to reach on the shelf and select a brace that approximates your dogs size. If they refer to the brace by a # or letter, it is most probably off-the-shelf. Even in large breeds, lameness due to this injury usually decreases with conservative treatment and time. However, if instability of the knee remains, it may lead to arthritis of the joint and eventual reluctance to use the affected leg. But no current surgical technique is a guarantee that arthritis will not occur. Also important for long-term management of your pet, is returning it to its optimum body weight when it is overweight. Providing regular moderate exercise and increasing your pet's exertion level very very gradually is also important. Be sure to cut back the level of exercise at the first sign of knee discomfort in your pet. Surgical Treatment Of Torn Cruciate Ligaments There
are a large number of surgical techniques that are purported to
None of them available as of the spring of 2011 work satisfactorily. The problem with all surgical techniques is that they do not restore stability to the joint. Without stability, the dog’s femur “rattles” around on its tibia destroying the remaining cartilages and leading to eventual arthritis, loss of mobility and pain. No surgical technique will restore your pet's knee if it does not replace the torn cruciate with a material of similar elastic consistency placed in the same crucial location as the original ligament. The stifle is a perfectly designed joint for what it must do – and God placed the cruciate where it is for a reason. This natural ligament is in the ideal location to modulate the forces of motion as your dog walks. Current surgical techniques ignore this point because the cruciate is located in such an inaccessible location. This can be very hard for owners and veterinarians, alike, to accept. The cruciate is a crucial part of a hinge – similar to the ones on your door. It has to be in the right place and made of the right materials to work. Place it somewhere else on the door and it will not open or close correctly. Eventually it will fail. Construct it out of the wrong materials and it will not last long or work right. A replicate cruciate ligament for your pet would need to have the same superb elastic and strength characteristics of the original elastic cartilage. Until biomedical engineers and surgeons come up with elastic material, placed in the appropriate place, it will remain a very imperfect surgery with generally disappointing results. Perhaps someday, nanotechnology or regenerative medicine will help these pets. But for now we have an unsolved engineering and materials question that needs a solution. "If all you have is a hammer, everything looks like a nail" This fact is very hard for owners and veterinarians to accept. Owners desperately want a cure for the pet they love. So much so that, according to one source, they spent 1.32 billion dollar in 2003 attempting to help their pets through cruciate pain. Currently, five times as many dogs undergo cruciate surgery in the US as people - even though people outnumber dogs nearly five to one. The sheer number of surgical techniques currently in use show that no one is really satisfied with their results. The ones touted as being the best tend to be the ones that have been around the shortest period – the “fresh faces on the block”. The highest success rate statements are generally for the procedures being done for the shortest length of time. If past history is any guide, as time goes by, more complications and lower success rates will appear and surgeons will move on to another procedure. One of the few scientifically conducted studies on the success rate of these techniques was conducted in 2005 at Iowa State University. It can be faulted when used as a verdict on success rates because the pets involved had meniscal cartilage damage as well as cruciate tears - not all cruciate cases do – but it is the only impartial study of its kind that I know of. Here are some of the techniques your pet may be offered: LSS (lateral suture stabilization)
A 2005 study found that 14.9% of dogs undergoing this surgery ICS (intra capsular over-the-top stabilization surgery)
The same 2005 study found that 15% of dogs undergoing this surgery TPLO (tibial plateau leveling osteotomy surgery) This technique changes the angle at which the tibial portion of the pet's knee rides on the pet's femur on the theory that a functional stifle can be obtained by redirection of forces. However, in a study of 150 dogs published in 2008, researchers found that there was no evidence that the a pet’s TPA (tibia plateau angle) predicted the rupture of the second knee cruciate in dogs. That is, extremes in the angle this surgery corrects do not in themselves cause the cruciate to rupture. The
2005 study found that 10.9% of dogs undergoing TPLO surgery An article in the November 2007 issue of Clinicians Brief states that TPLO does not stop or reverse the progress of osteoarthritis in the knees of dogs with cruciate ligament tears. The chairman of the Orthopedics Department at U. of Pennsylvania's School of Veterinary Medicine has bee quoted as saying: "The TPLO doesn't seem to have any great advantage over more conservative forms of treatment". and, in another correspondence, as stating : “There is no evidence based studies to show that the results are any better than traditional surgeries and the invasiveness & cost is much higher. The morbidity is also much higher & therefore at U of P- we do not do it”. Tightrope (TR CCL) surgery procedure This rather-recent procedure attempts to temporarily stabilize the pets loose stifle with a fiber tape that slowly disintegrates. The theory presented is that permanent scaring of the pet’s joint capsule will eliminate or improve joint stability. To the best of my knowledge, no hard evidence or explanation is presented as to why this technique is superior to other extra-capsular techniques and orthotics that are currently out of favor (Fascia Lata Imbrication, Lateral Retinacular Imbrication, DeAngelis technique, etc.) On a webview attributed to Arthrex Vet Systems, the manufacturer of Tightrope CCL, appears this statement: “Your dog has or will develop arthritis associated with the cruciate ligament problem – this will not be cured with surgery or medication so we will need to manage this for the rest of your dog’s life” A white paper from the manufacturer states that 6-months outcomes are “as good or better than TPLO”. Considering the questionable results of TPLO, this is nothing to brag about. If
you do decide that your pet must undergo knee surgery, I suggest
an extracapsular technique similar to this one. Less damage is done
within the joint, recovery is faster and results are as satisfactory
as any. There is also less risk of infection than when the joint
is opened. Be sure that antibiotics are prescribed after surgery.
(ref) TTA (tibial tuberosity advancement surgery) This
new surgical method uses the same defective reasoning used to justify
TPLO surgery. Its chief advantage is that it is a less-involved
extra-capsular procedure that does less damage to the joint than
TPLO and costs less to perform. FHT (fibular head transposition surgery) Research published in 1994 identified this once widely-performed surgical procedure for torn cruciates in pets as worthless .
All veterinarians want to heal pets. Veterinarians in general practice know that they have no silver bullets to deal with cruciate ligament tears. So they are likely to pass you along to a specialist, just as your general practice physician will do when he suspects a difficult case. There are many very good general-practice vets who truly believe these procedures work and want you to be aware of them. But there are also several problematic incentives for sending you to a veterinary surgeon rather than advising patience. If your veterinarian advises patience, physical therapy and medical management of your pet’s knee and it gets better, the outcome for the vet is neutral. But if it gets worse or does not return to full function (as it may), you might blame the vet. In many states in the US, there can also be severe licensing and liability repercussions to your veterinarian if he does not refer you to a specialist. Orthopedic surgeons, human or veterinary, feel the need to practice their specialty. If they were not enthusiastic about their craft, they would work in other fields. But this exuberance can lead to excesses. For example, commonly performed arthroscopic surgery for knee arthritis in humans is usually worthless. and many feel that surgical cruciate repair in people is often unnecessary as well. I am very proud of the free enterprise and entrepreneurship that exists in the veterinary profession in the United States. Because of it, your pet has better health options here than anywhere else on Earth. But making intelligent pet health choices will always pit pet owners against the never-changing nature of commerce and enterprise – when you visit the fresh fish store, what are you likely to leave with? How Can I Avoid Cruciate Ligament Problems In My Pets In The Future ?
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