Why do you think we are having such a high occurrence of cruciate injuries in our breed? Hoping for an insightful, intelligent conversation here.

Because of the popularity of over angulation in the rear. People see those rears, and think they are gorgeous. But they are structurally incorrect, and thus lies the problem. Over angulation creates weakness.

Actually I tend to disagree, I've seen it more in dogs with straight stifles than over angulated dogs.

JMO - over feeding & over exercising at too young an age are contributors.

I have had two cruciate injuries and both are correctly angulated - neither straight nor overangulated. I think there is more to it than that.

In the case with my girl she was very bowlegged as a pup and as an adult. I mean, VERY.
She also had weak patellas. Combined the vet said this put her at a higher risk of cruciate injury.
She has great hips. But it is obvious to me now that she compensated for her poor patellas by shifting all her weight to her front and by a 4 years of age she was weaker in her rear and loaded in the front.
I was doing agility with her. Very small jumps, not even close to her jump height. Mostly she just liked to do the tunnels and weaves.
But her weak leg structure, bowleggedness, patellas and repetitive work caused her cruciate to rupture.
By the time it ruptured she was also taking prednisone which in turn also caused muscle atrophy. She had so many strikes against her, who know what the real cause was.
I think over and under agulation can both be a cause as well as many other factors.

Rough house play between the dogs at 1 year to 2 years , all it takes is one good body slam to do the damage.

As a DVM, straight stifles is the cause. Also, injuries - running big boned labs on cement will cause their joints to break down. It can happen jumping up or down, especially UP into the back of the Van, on the couch, on the bed,rough play, flying off a dock/land or high place and then crash landing hard on the surface below.

It is better to have some angles in the stifles,
this gives the joint some slack compared to a straight
stifle that is pulled so tight its like a rubber band just waiting to snap.

Myth or not? I have heard that this is hereditary? I have a bitch that tore hers tracking on wet grass. I seen her slide into a turn and it was all down hill from there. She was around 7 months but managed to get her TD before the limping showed up full time.

I don't know. I let my last three dogs do what they wanted and even ran one in agility and got a title before she was 2. My male use to run full speed the length of my house in my basement and use the wall to stop himself. We had to replace that part of the wall twice. He has passed clearances and has never had an injury. How he managed that is sometimes a miracle.
My 3.5 year old girl was also hell on wheels. She and my male would rough play a lot. She also, like him, never used the steps on the deck. They just jumped off it. She also passed, no injuries.
Now I do think certain reoccurring repetitive stress to the leg/s can result in the injury.
My youngest is the same as the first two. She is too young for final OFA but she has never had a cruciate injury. And she is a little jack rabbit.

Slack was not the word I should have used. What I meant to say is that having some angulation in the rear is a much more desired conformation in the stifle joint, than a straight stifle.

It can also happen from another dog body slamming into another dog. There are so many ways it can happen, but correct stifle conformation to begin with, eliminates the chances of this injury happening as often as it does in dogs with straight stifles.

Early spay/neuter and overweight dogs.

There is definitely an autoimmune component involved and with the wide use of MLV vaccines, it is no wonder why we are seeing a vast increase in the incidence:
http://www.puliclub.org/CHF/AKC2007Conf/Canine%20Degenerative%20Cruciate%20Rupture.htm

As somebody else said, there are lots of dogs who tear around and don't get injured. To that end, maybe there is something that initiates the tear.

As for the genetic component, I know of two lines where cruciate tears are very common. I have a dog from one of them and this dog also has major autoimmune problems. The ligament should be able to withstand normal forces, so the cause is likely not the force, rather a combination of what the dog brings to the table: autoimmune disease causing synovitis, structure, weight, etc.

This was actually brought up in discussion at my local hunt test club a few years ago ... we had a two board certified orthopedic surgeons speaking to us .... One of them told us that there is some speculation that with the improvements in hips we are actually seeing more cruiciates ... one hypothesis was that the genes associated with good hips were also associated with an angle change in the knee that actually made crutiate tears more likely.... Not that we want to move away from continuing to improve our hips by any means .... just interesting that if you change one thing it can affect a whole different set of things that weren't really as prevelant before.
I don't know if anyone actually followed thru and did a study ... it would be very interesting to find out.

What is MLV vaccines ?

In 16 yrs of owning large breed dogs and 14 yrs of owning Labradors, it wasn't until we purchased our current foundation bitch that we had our first Torn Cruciate. She healed on her own with crate rest and was only a parital tear. So far her son out of 1 litter ruptured his cruciate and had to have surgery on the one knee. Then a 2nd offspring of this same dam tore her cruciate good. The boy who tore his cruciate when he was 6 months old was very athletic, not over weight. They had been tossing his frisbee and the dog landed on their cement steps just the wrong way, causing the injury.The 2nd offspring who recently tore her cruciate is about 15 pounds over weight. They are trying to get the weight off of her then they will have their vet do the surgery.

Out of 3 litters with this one girl of ours, only 2 have torn their cruciates so I don't know what to make of it. I'm currently picking stud dogs who have very muscular rear ends with nice angles in the hopes of improving my bitch lines in this area. I don't think my girls are too straight and they look like they have normal stifles. Their hips all came back "Good" from OFA and normal elbows.
I do think there is a certain amount of genetics behind Cruciate Injuries.

I'd also hate to think that while we have all been trying to improve the hip scores, the structure of our dog's knees have changed so much that it is causing more injuries. I'm not sure I buy this theory altogether but it is an intersting one to follow.

Question - is there really an increase in these injuries, or are we just hearing more about them due to improved communication on the internet? Or because there are more specialists that repair them? Or that more people are willing to spend money at the vet? Or that more are being reported even though there might have been the same amount that we just hadn't heard about? Or some other factor? Just wondering if there are studies that verify what we seem to be seeing.

Per my orthopaedic surgeon:
"The tendency for that particular cartilidge to be weak is hereditary". I believe it.

I had two ACL injuries here. One a complete rupture, the other a partial tear. I had the same surgeon do both surgeries. When I went in for the second one, he told me, "It's nothing you did and it's nothing you didn't do. Your dog was genetically pre-disposed to this injury." He broke it down further, saying that "there is so much weight on such a little joint and that the only thing keeping it in place are two criss-cross ligaments. Our dogs are actually destined for such injuries from birth, as they are poorly constructed."

There isn't anything that we can do to change that, unless someone has an in with God and can ask him to alter his breeding program.

I have seen 5 from the same "lines" with bilateral ACL tears all of which required TPLO's. Conformation was good on all-they were not over angulated nor too straight-kept lean growing up and 4 were house pets, only dogs so no rough play. I think there is a strong hereditary link and when we keep convincing ourselves these are all "injury" related we are only fooling ourselves-same as "seizures can be caused by many factors" True- but when you start to see it run in certain lines than we know we are holding onto to something that should be let go. As one of the previous posters said her boy ran into walls, the girls played hard-they are fine-luck, I don't think so. I thing there must be the underlying hereditary link present before environment, weight, circumstances etc will "bring it out"-same as hips, seizures etc.

There is an increase in ACL injuries in people too and it's thought that it's due to trends of our population getting fatter in this country. Cruciate ligament injuries in dogs now outnumber those in people .

Hmm, interesting. Is it the weight or the lack of conditioning and coordination that goes with it? Ligaments and joint capsules have receptors in them that help to correct the joint on uneven terrain or with unexpected changes of direction. People and dogs who are not routinely exercised (not including walking) will have less functional stability in their ligaments.
Interesting.
There was also a study done on young girls as they found that females are more likely to suffer cruciate tears because they are quadricep dominant and the opposing hamstrings help the ACL (human equivalent to the CCL) to decrease shearing forces. When they took a large sample of young girls and taught them conditioning exercisee which promoted better hamstring strength and recruitment, long term follow up and loading studies showed better ACL strength and a lower incidence of injury.

Here is some information I found on the web when I googled "anterior cruciate ligament+canine".

http://www.marvistavet.com/html/body_ruptured_anterior_cruciate_lig.html

My boy is neither over, nor under, angulated and not overweight. He is active, and had a CD and JH under his belt when a quick turn in the yard (well, his leg turned, but the foot did not) did him in. We were there when it happened and took him to the vet when the limping didn't subside after a week, or so. We were told that ligaments don't heal, that a partial tear will typically result in a full tear (if it truly was a torn ligament to start with). We had the TPLO surgery done 2 years ago when he was 4 years old and today you would never know he had a problem. No limping, still active, running, jumping, etc. I'm happy to say.

My only cruciate tear was 26 years ago in one of my foundation bitches. She was only 10 months old and one of the ones that jumped high in the air and worried about where she would land on th eway down. We think she landed in a gopher hole. None of her descendents to my knowledge has had a cruciate tear. Maybe there is a genetic tendency in some lines, but I am convinced that for her it was an accident with no predisposition except maybe her reckl;ess temperament as a puppy. She had the type of surgery in which the knee is stablized by a piece of connective tissue. She went on to earn a JH and a CDX at the time when the jumps were still high.

MLV is Modified Live Virus, as opposed to Killed, vaccine.

Why don't we just blame everything on vaccines? Oh, and kibble.

Cruciate problems are NOT just Labrador problems, it is the #1 ortho problem in ALL dogs, regardless of breed.
Maybe we better ask the maker what's up with those doggie knees

Perhaps the increase is because everyone gets them repaired, and then breeds them.

Northwest breeder, I have come across the same information, that exercise and streching prior to sports can reduce the incidence of ACL injuries in people.

I would venture to say that there is more than one underlying cause of ACL rupture in dogs. Therefore, the reason one dog has the injury is not necessarily the same as the reason another dog has the injury. It seems that being straight in the rear and being overweight are seen often (but *not* always) in dogs wtih ACL ruptures. There are also those dogs that frequent in activities such as frisbee and ball chasing that involve running fast with sudden sharp turns- in some of these cases it likely is a true injury not related to any other factor. There has also been the statistic that more than 50% of dogs who rupture one ACL will go on to rupture the other (I personally have not seen this bear out in private practice). However, bilateral acl injuries would lend to the suggestion that there is some inherent weakness in the ACL of those dogs. It could be auto-immune and may or may not be hereditary (could easily be any combination of the two).

But bottom line is that some dogs likely have a true injury, others have poor structure that lends to added stress on the stifles, and yet other dogs may have an immune-mediated weakness of the ligament. Straight rears are likely hereditary to a certain extent, as could be the immune-mediated.

I don't think I am personally seeing any more ACL ruptures than I used to. I do think more clients now are willing to persue referral for surgical correction. I will try to ask a couple of surgeons if they think the true incidence is higher now.

I have had two ACL bitches. One tore hers while jumping out of a van heading into the ring (broke my heart). She had a TPLO and came back to be competitive. The second tore hers while she was running in the dog yard. Slipped and fell, Bamm, torn. She had a regular nylon banding surgery by a great vet. She didn't come back to being competitive and just recently tore the other knee (4 weeks ago). She is recovering now.
I questioned my vet about keeping this last in our breeding program. She is beautiful but done from the show ring. He believes that some dogs have a tendency to be bow legged in back and that has led to the increase in ACL tears. This man does 12+ a week from all over MI and IN. It is not just Labs. When I walk in the clinic on "ACL Day" I see primarily Rotts, Goldens and Labs. MANY mixes too.
As for my , I will keep her in the program but carefully watch who I breed her to. None of her siblings have ACL problems. We shall see...
I wish there was a study we could all do???? ANyone know of one or want to take it on? Maureen????

If it's any help, I will add that I think being "bowlegged" is a major contributor to cruciate injuries in dogs. One of my girls is clearly bowlegged and has great hips(OFA'd Good, Elbows Clear). She ruptured a cruciate at a year of age running out back(in our woods) in the dark with the other dogs. She's the only dog produced out of all of my dams that has this noticeable defect. She is also high in the rear which makes her straighter stifled. She was spayed; never bred and we love her as a house pet.

Her injury was surgically repaired using the traditional technique with modifications. She's been very sound and we don't limit her activity except that I forbid any fetch games.

Just curious who you went to, to have the ACL surgeries done? It sounds like things worked out well for you and interested to get more information from you on recovery time etc...

I think at least some of this is due to the "weekend warrior" syndrome. These dogs by nature, have a lot of drive. Not being in working condition does not deter them from going all out.