Dog Hip Dysplasia

PennHIP Radiographs – improving hip dysplasia diagnosis

Posted on in Dog Hip Dysplasia, Radiographs Comments Off on PennHIP Radiographs – improving hip dysplasia diagnosis

Diagnosing Canine hip dysplasia using PennHIP

 

Canine hip dysplasia is a well recognized genetic condition in dogs that can cause hip arthritis, chronic pain, and sometimes requires surgery. Over the last fifty years, breed organizations and kennel clubs have attempted to remove the disease from the population through selective breeding. Despite this effort, little progress has been made. This may be in part due to the under utilization of the PennHIP radiographic technique.

Normal dog with hip joints PennHIP compressed

Normal dog with hip joints PennHIP compressed

 

 

OFA (Orthopedic Foundation for Animals) Radiographs

Selecting dogs that are considered “hip dysplasia free”, those considered unlikely to pass the condition onto their offspring, has largely been based on their OFA radiograph findings – by x-raying the appearance of the hips while the dog is lying on its back with its legs in full extension.  Unfortunately, research has shown that OFA radiographs are a poor test for screening against hip dysplasia.

OFA radiographs are a poor test because although they select for dogs with good hip conformation, they does not test for soft tissue laxity, a key component in the development of hip dysplasia. As a result, many dogs that pass their OFA radiographs have now been shown to have lax hips This is likely the reason that efforts to eliminate the disease have not worked. Research has found that breeding dogs with passing OFA radiographs results in hip dysplasia in anywhere from 19% to 73% of the offspring.

PennHIP (Pennsylvania Hip Improvement Program) Radiographs

PennHIP radiographic testing was introduced over 20 years ago, and tests both hip conformation (as does OFA) as well as tissue laxity. It is a more sensitive test than OFA radiographs, meaning that it will detect cases of hip dysplasia that otherwise would be missed. In order to breed hip dysplasia out of the gene pool, it is key that all dogs potentially carrying the condition are detected, and therefore the test needs to be as sensitive as possible.

 

Normal dog with hip joints PennHIP distracted - the joint space has been highlighted blue. Notice how little difference there is between the hip compression and distraction view. This indicates a stable hip joint.

Normal dog with hip joints PennHIP distracted – the joint space has been highlighted blue. Notice how little difference there is between the hip compression and distraction view. This indicates a stable hip joint.

Which is better?

Side by side comparison of OFA and PennHIP radiographs found that none of the dogs that failed their PennHIP radiographs, passed their OFA radiographs, but many dogs that passed their OFA radiographs, failed their PennHIP radiographs. In fact, two of the dogs with “excellent” OFA ratings had some of the worst PennHIP scores, indicating a high probability of developing hip arthritis secondary to tissue laxity later in life.

Another limitation of OFA radiographs is that scoring is based on subjective evaluation. This means that the same radiographs may get a different score depending on who is reviewing them, or even if the same radiologist reviews them on different days (with a different mood, fatigue level etc.). This problem is reduced with PennHIP radiographs because the results are based on measurements and the calculation of a distraction index, which is less likely to show variation between radiologists.

OFA radiographs require the dog to be at least 2 years of age before testing, whereas PennHIP radiographs have been shown to be accurate in predicting the onset of hip dysplasia as early as 4 months of age, allowing for earlier testing.

Conservative estimates based on mathematical models indicate that for a breeder of Labrador retrievers hoping to eliminate hip dysplasia from their line, using the PennHIP system will accomplish that goal 4 times faster than by relying on OFA radiographs.

Although some dogs receiving OFA radiographs may not need sedation, sedation is mandatory for PennHIP radiographs in order to relax the muscles enough to properly appreciate the degree of connective tissue laxity.

Hip dysplasia PennHIP compression view - notice how the dog's left hip joint space (right side of picture) has an irregular width

Hip dysplasia PennHIP compression view -notice how the dog’s left hip joint space (right side of picture) has an irregular width

 

Who should Consider PennHIP?

Any breeder who is serious about producing a line of dogs free from hip dysplasia should employ a PennHIP screening program. Pet owners and dog handlers who want to invest in a dog suited to an active life style, working, or competition, should also consider only purchasing PennHIP cleared dogs. Dogs can be tested for hip dysplasia using the PennHIP method as early as 4 months of age.

If you have any further questions about PennHIP testing in BC, please email info@pointseastwest.com

 

Hip dysplasia distraction view - notice how much wider the joint becomes once it is distracted, compared to the normal dog.

Hip dysplasia PennHIP distraction view – notice how much wider the joint becomes once it is distracted, compared to the normal dog.


Tubal ligation or vasectomy for dogs

Posted on in Canine Cruciate Ligament Rupture, Dog Hip Dysplasia, Prevention, Puppy Care 8 Comments

When to spay or neuter my dog?

(Part 2)

Should I spay or neuter my dog, or get a tubal ligation or vasectomy instead?

 

This is a continuation of the 1st blog that looks at the issue of finding to best age for spaying or neutering your dog.  If you haven’t read part one, then you may wish to before forging ahead.

In part one, I alluded to new information that recently became available about possible risks associated with spaying or neutering your dog – research that was done at the UC Davis Veterinary Collage in California and is available online here.

PWD runningThe paper reviewed the medical records of 759 golden retrievers, and compared the incidence of hip dysplasia (HD) and cranial cruciate ligament tear (CrCL), as well as the incidence of several malignant cancers including lymphsarcoma (LSA), hemangiosarcoma (HSA), and mast cell tumours (MCT).

The study found some troubling results.  We don’t yet know if these findings can only be applied to golden retrievers or to other breeds as well, but until further research answers that question, the safer approach is to consider that other breeds might yield similar results. The visla club did an informal survey that would not stand up to rigorous scientific scrutiny, but none-the-less found an increase in cancer in spayed/neutered vislas compared to intact ones.

For purposes of this study, early neutered males are defined as males neutered before 12 months of age.

Summary of results:

 

Hip Dysplasia

  • The incidence of HD in early-neutered males was 10.3%, more than double the incidence in in-tact or late-neutered males.
  • The incidence of HD in spayed vs in-tact females was the same

 

Cruciate Ligament Rupture

  • The incidence of CrCL rupture in early-neutered males was 5.1%.
  • In early-spayed females, it was 7.7%.
  • CrCL rupture was not diagnosed in any of the in-tact animals studied, and in only 1 of 72 late neutered males.

 

Lymphosarcoma

  • Early-neutered males had nearly three times the occurrence of LSA when compared to intact males.
  • No LSA was detected in late neutered males
  • There was no statistically significant difference in the incidence of LSA in spayed vs intact females

 

Hemangiosarcoma

  • Late-neutered females had a 7.4% incidence of HSA, over four times that of intact females (1.6%), and in early-neutered females (1.8%)
  • No differences were found between intact and neutered male dogs in the incidence of HSA

 

Mast Cell Tumour

  • MCT did not occur in the intact females but was diagnosed in 2.3% of early-neutered females and 5.7% of late-neutered females
  • Neutering did not affect the incidence of MCT in male golden retrievers

 

Now what?

 

That’s a good question… and no clear answer is going to come out of these murky waters.  I tried to make things simpler by making a chart (see below).

 Female dogs:

early spay

late spay

intact

Mast Cell Tumour 2.3% chance 5.7% chance less risk
Hemangiosarcoma 4x increase no increase no increase
Lymphosarcoma no effect no effect no effect
Mammary Tumour very low risk low risk very high risk
Cruciate Rupture 7.7% chance under 1% chance under 1% chance
Hip Dysplasia no effect no effect no effect
Urinary Incontinence high risk very high risk(?) low risk
Aggression/Roaming NA NA NA

 

Male dogs:

early neutering

late neutering

intact

Mast Cell Tumour no effect no effect no effect
Hemangiosarcoma no effect no effect no effect
Lymphosarcoma 3x incidence no effect no effect
Mammary Tumour NA NA NA
Cruciate Rupture 5.1% chance under 2% chance under 2% chance
Hip Dysplasia 10.3% chance under 5% chance 5.1% chance
Urinary Incontinence NA NA NA
Aggression/Roaming decreased risk unknown high risk
Reactivity/Fearfulness decreased risk unknown high risk

 

BC Yukon regional championshipsI would also like to add these thoughts into the mix:

  • Intact males are more likely (in my opinion) to be attacked by other male dogs (intact or neutered). I’ve personally known many intact male patients that developed significant inter-dog fear and/or aggression issues secondary for being repeatedly attacked.  These issues greatly impacted quality of life.  

 

  • Pyometra is a common and potentially life threatening infection of the uterus that occurs almost exclusively in intact females.  One Swedish study found that 24% of intact females will get a uterine infection by 10 years of age.

 

  •  Testicular tumours only affect intact dogs and are common in dogs older than 10 years of age.

 

  • For male dogs, the issue seems to be balancing the risk of health issues against behaviour issues – a rock and a hard place.  For females, the choices seem even less clear, with health issues being raised not matter what you decide.

 

  • The only way to guarantee that your dog will not contribute to the pet overpopulation problem is to have him/her neutered/spayed.  One lapsed moment with a dog in heat can lead to 8 unwanted puppies – and even if you find a home for those 8 puppies, that just means that 8 other puppies somewhere else don’t get a home and have to be euthanized.

 

Tubal ligation or vasectomy for dogs

 

If, based on the above information, you decide that you want to keep your dog sexually intact, then getting a tubal ligation or vasectomy is the only way to guarantee that you do not contribute to the overpopulation problem.  Tubal ligation or vasectomy for dogs is the same procedure as it is for people; the vas deferens in males, or the fallopian tube in females, is severed and tied off.  This will render your pet incapable of producing puppies, yet still maintain the same sexual hormone levels as an intact dog.  The procedure is about the same complexity as a spay or neuter. However, by leaving the uterus behind, female dogs are still at risk for pyometra. Therefore, a hysterectomy, in which the entire uterus is removed but the ovaries are left behind, might be a better option.

For owners wishing to keep their dog sexually intact, the only way to guarantee that no unwanted puppies are produced is to have a vasectomy or tubal ligation/hysterectomy.


What age to spay or neuter my dog?

Posted on in Canine Cruciate Ligament Rupture, Dog Hip Dysplasia, Prevention, Puppy Care 3 Comments

What age to spay or neuter my dog?

(Part 1)

 

Sometimes I yearn for the ‘good ol’ days’.  Back then, if a client wanted to know when or at what age to spay or neuter their dog, the dialogue went like this:

Client: “What age should I spay (or neuter) my dog?”

Me: “At six to seven months.”

Client: “Ok.”

… and then we would talk about something else.  It was a quick and easy conversation that required very little thought.

Now when a client poses that same question, my answer starts with “Well, that depends…”, and then devolves into a ten minute lecture full of conflicting information.  It is no longer a simple question with a simple answer*, and my advice differs depending on who I’m talking to.

The incidence of orthopedic conditions such as cruciate ligament rupture or hip dysplasia are affected by the age that the dog has been spayed or neutered

Orthopedic conditions such as cruciate ligament rupture or hip dysplasia are affected by the age that the dog has been spayed or neutered

*Ironically, I had first started writing this blog on the flight back from the WAO worlds in Spain just a few months ago, and since that time more information has come forward that complicates the issue even further.  Now the question isn’t just “At what age should I spay or neuter my dog?” but also “Instead of a spay or neuter, should I consider a vasectomy or tubal ligation for my dog?”

 I was originally going to incorporate both questions into the same blog, but that just made my long rambling explanation even longer, so I decided to tackle the vasectomy/tubal ligation question in part #2.  So for now, let’s just address the question of what age to spay or neuter your dog.

 So, where was I?  Oh ya….

The reason why this question is so much more complicated to answer these days is because now we know a lot more than we used to about the effects of spaying or neutering at an early age.  There are benefits and there are drawbacks. We’ve known about the benefits for some time but have only learned about the drawbacks more recently.  Here is an overview of the many factors to be considered:

 Mammary Tumours

Exiting the tunnel at the BC/Yukon regional agility championships

Exiting the tunnel at the BC/Yukon regional agility championships

Mammary tumours are the single most common type of tumour found in in-tact female dogs.  Although most dog mammary tumours are benign, as many as 1 in 5 in-tact female dogs will develop malignant breast cancer in their lifetime.1,2  Other research has shown that the risk of breast cancer is almost non-existent in dogs that have never gone through heat.  By spaying your dog before the 1st heat, you reduce the chance of breast cancer by 99.5% compared to intact dogs.  By spaying after the 1st heat but before the second heat, you reduce the chance of breast cancer by 92%.  If you fail to spay your dog before 2.5 years of age, or before they have gone through 2 heats, your dog is just as likely to develop malignant breast cancer as a dog that has not been spayed at all3. However, spaying after the 2nd heat may still reduce the chance of benign mammary tumours from forming4.

 Bottom Line: Spaying before your dog’s 1st heat, and especially before the 2nd heat greatly reduces the chance of developing malignant mammary tumours during their lifetime.  Spaying after the second heat won’t reduce the incidence of malignant cancer but may reduce the chance of benign cancer (and the surgery that goes with it).

 Urinary Incontinence

Urinary incontinence is uncommon in intact female dogs, but relatively common in spayed females.  The incidence of urinary incontinence due to spaying is estimated to range from 3 to 21%, depending on the researcher5-18.

Other factors are at play as well, including breed genetics and size of the dog. One study of boxers found that 71% were likely to develop urinary incontinence if they were spayed after their 1st heat, but if they were spayed shortly before their 1st heat, that risk could be cut in half19-21.

Another study found that dogs spayed before 3 months of age were more likely to develop urinary incontinence22.

 Bottom Line:  Spaying your dog increases the chance of urinary incontinence.  It would appear that to minimize this risk (in boxers anyway), the best time to spay your dog is shortly before her 1st heat.

 Musculoskeletal Effects

This patient received a TPLO to repair a ruptured cruciate some time ago

This patient received a TPLO to repair a ruptured cruciate some time ago

It has been demonstrated that spaying or neutering before your pet is fully grown won’t change the rate of growth, but it will delay the closure of growth plates23,24.  This results in a longer leg length when compared to intact dogs.

It is also believed that this may contribute to a steeper slope of the tibial plateau, which has been identified as a cause of cruciate ligament rupture.  Spayed or neutered dogs are two to three times as likely to rupture their cruciate ligaments as intact dogs are25,26.  Spaying females before six months of age makes them 1.6 times as likely to rupture their cruciate ligaments26. At this time, there is no reason to believe that spaying or neutering a dog after it is fully grown predisposes it to cruciate disease.  One school of thought is that the later you delay the age of spaying/neutering, the less the chance of developing cruciate disease, up to 17 months of age.  This theory is supported by the data that will be discussed in part 2 of this blog.

One study found that 6.7% of dogs neutered before 5.5 months of age developed hip dysplasia, whereas dogs neutered between 5.5 and 12 months of age only had a 4.7% incidence27.

 Bottom Line: Delaying spay and neutering until after your dog is fully grown will reduce the chance of rupturing the cruciate ligament down the road.  Waiting until your dog is at least 6 months of age will reduce the chance of developing hip dysplasia.

  Behavioural issues

The increased incidence of aggression and other undesirable behaviours in intact males is well documented28-32.  Neutering before the onset of puberty is one way to decrease the chance of these behaviours from manifesting.  Researchers concluded that neutering decreases inter-dog aggression by 62%, and roaming by 75%.  Dogs neutered earlier in life tend to be less reactionary33,34.

 Bottom Line: To avoid aggression and other undesirable behaviours, neuter male dogs before puberty.

 So what do you recommend?

Again, the bottom line answer is “Depends”.  It depends on who the client is, and who the dog is.

 Shelter Dogs

If the client represents an animal shelter, whose primary concern is to not contribute to the pet overpopulation problem, I recommend spaying or neutering all dogs before they get adopted out, from 7 weeks of age upward.

 Non-Shelter Dogs

 Female Dogs

For the owners of female dogs, one has to weigh the risks of malignant mammary cancer against those of potential cruciate ligament rupture or hip dysplasia.  If I had to choose between the two, I would rather have a ruptured cruciate ligament than malignant cancer.  For that reason I generally recommend spaying as late as possible before the first heat – 7 months of age in smaller dogs, but closer to 10 months in very large dogs.  That is what I would do if it were my dog, except of course this issue gets more complicated with part 2 of this blog.

However, for working, or competition, or otherwise very athletic dogs, cruciate ligament rupture is not something to be taken lightly.  For that reason, some owners take the opposite approach and make it a priority to minimize cruciate disease by not spaying their dog before 17 months of age, and cross their fingers that she doesn’t go through a second heat before then.  Others choose to split the difference and spay their dog at 17 months of age, or 5 months after her first heat, whichever comes 1st.  In doing so, they still maintain a 92% reduction in the likelihood of breast cancer, and minimize the risk of cruciate ligament rupture at the same time.

 Male Dogs

Other factors can also play a role in the decision of when to spay or neuter – these two testicles came from the same patient, but one was cryptorchid or “retained” inside the body wall, so never grew to a normal size. Retained testicles are more likely to develop testicular cancer.

Other factors can also play a role in the decision of when to spay or neuter – these two testicles came from the same patient, but one was cryptorchid or “retained” inside the body wall, so never grew to a normal size. Retained testicles are 13 times more likely to develop testicular cancer.

Male dogs don’t face the same risk for malignant breast cancer as a result of not being neutered before puberty.  However, the onset of puberty can lead to undesirable behavioural issues.

For routine family situations, I recommend neutering male dogs before puberty.

For working, or competition, or otherwise very athletic dogs, many owners elect to delay neutering until 17 months of age.  They monitor their dog for behaviour changes, and respond by neutering earlier if they see unwanted changes following the onset of puberty.

All owners who delay spaying or neutering until after puberty need to remain hyper diligent about preventing unwanted puppies.  The only way to guarantee that a sexually mature dog cannot reproduce is to have a vasectomy or tubal ligation performed.

I hope this helps… It’s a complex issue with no clear best answer for all situations.  Hopefully though, by learning about the major pro’s and con’s, you are in a better position to decide what is best for your individual situation and for your pet.

As promised, part #2 of this blog will be posted soon.  It will discuss the concerns with spaying or neutering your dog vs. electing for a vasectomy or tubal ligation instead.

 Footnotes:

 

1 Dorn, C. R., et al. J Natl Cancer Inst 1968, 40, 307-318.

2 Moulton, J. E., et al. Vet Pathol 1986, 23, 741-749

3 Schneider, R., et al. J Natl Cancer Inst 1969, 43, 1249-1261

4 Phillips, B. S., Western Veterinary Conference, 2002

5 Angioletti, A., et al. Veterinary Research Communications 2004, 28 Suppl 1,

153-155

6 Arnold, S., et al. Schweizer Archiv für Tierheilkunde 1989, 131, 259-263.

7 B.S.A.V.A. Veterinary Record 1975, 96, 371-372.

8 Blendinger, C., et al. Tierarztliche Praxis 1995, 23, 291-299.

9 Holt, P. Journal of Small Animal Practice 1985, 26, 237-246.

10 Joshua, J. O. Veterinary Record 1965, 77, 642-646.

11 Okkens, A. C., et al. Journal of Reproduction and Fertility Supplement 1997, 51, 227-231.

12 Okkens, A. C., et al. Tijdschr Diergeneeskd 1981, 106, 1189-1198.

13 Osborne, C. A., et al. In Current Veterinary Therapy Kirk, RW., Ed.; WB Saunders:1980, 1128-36.

14 Reichler, I. M., et al. Theriogenology 2005, 63, 2164-2180.

15 Ruckstuhl, B. Schweizer Archiv für Tierheilkunde 1978, 120, 143-148.

16 Stöcklin-Gautschi, N. M. Dissertation Vet.-Med. Fakultät der Universität Zürich: Zürich, 2000.

17 Stocklin-Gautschi, N. M., et al. Journal of Reproduction and Fertility Suppl. 2001, 57, 233-236.

18 Thrusfield, M. V. Veterinary Record 1985, 116, 695.

19 Arnold, S., et al. Schweizer Archiv für Tierheilkunde 1989, 131, 259-263.

20 Stöcklin-Gautschi, N. M. Dissertation Vet.-Med. Fakultät der Universität Zürich: Zürich,

2000.

21 Reichler, I. M., et al. Theriogenology 2005, 63, 2164-2180

22 Spain, C. V., et al. J Am Vet Med Assoc 2004, 224, 380-387.

23 Root, M. V., et al. Vet Radiol Ultrasound 1997, 38, 42-47.

24 Salmeri, K. R., et al. J Am Vet Med Assoc 1991, 198, 1193-1203.

25 Slauterbeck,J. R., et al. Clinical Orthopaedics and Related Research 2004, 301-305.

26 Witsberger TH, Villamil JA, Schultz LG, Hahn AW, Cook JL, 008, Prevalence of, and risk factors for, hip dysplasia and cranial cruciate ligament deficiency in dogs. J Am Vet Med Assoc 232, 1818-1824

27 Barnes K, Baltzer W, Incidence of cranial cruciate ligament rupture in dogs ovariohysterectomized at less than six-months of age, Veterinary Orthopaedic Society 39th Annual Conference, Crested Butte Co, 2012

28 Spain, C. V., et al. J Am Vet Med Assoc 2004, 224, 380-387.

29 Borchelt PL. Aggressive behavior of dogs kept as companion animals: classification and influence of sex, reproductive status, and breed. Applied Animal Ethology 1983;10:45-61.

30 Write JC, Nesselrote MS. Classification of behavioral problems in dogs: distributions of age, breed, sex, and reproductive status. Applied Animal Behavior Science 1987;19:169-78.

31 Hopkins SG, Schubert TA, Hart BL. Castration of adult ale dogs: effects on roaming, aggression urine spraying, and mounting. Journal of the American Veterinary Medical Association 1976;168:1108-10.

32 Maarschalkerweerd RJ, Endenburg N, Kirpensteijn J, Knol BW. Influence of orchiectomy on canine behaviour. Veterinary Record 1997;140(24):617-69.

33 Neilson JC, Eckstein RA, Hart BL. Effects of castration on problem behaviors in male dogs with reference to age and duration of behavior. Journal of the American Veterinary Medical Association 1997;211(2):180-82.

34 Hopkins SG, Schubert TA, Hart BL. Castration of adult ale dogs: effects on roaming, aggression urine spraying, and mounting. Journal of the American Veterinary Medical Association 1976;168:1108-10.

35 Maarschalkerweerd RJ, Endenburg N, Kirpensteijn J, Knol BW. Influence of orchiectomy on canine behaviour. Veterinary Record 1997;140(24):617-69.