PennHIP

THE PennHIP PROCEDURE

The PennHIP Procedure
The PennHip - Misconceptions and Misinformation - Fred Lanting

THE PennHIP PROCEDURE

http://www.thepetcenter.com

In 1937 veterinarian Gerry Schnelle wrote a paper entitled Bilateral Congenital Subluxation of the Coxofemoral Joints of a Dog. It was a landmark original description of what we today call Canine Hip Dysplasia. CHD for short, there are very few topics among dog owners, breeders, and veterinarians that can rival the spectrum of emotions evoked by this abnormality of the dog’s coxofemoral (hip) joint. The PennHIP procedure is a useful tool in determining the degree of hip joint laxity in dogs.

WHAT IS HIP DYSPLASIA
In short canine hip dysplasia (CHD) is a developmental abnormality of the hip joint. CHD is the most common orthopedic disease is dogs and is a polygenic (influenced by a number of genes) inherited trait. The radiographic changes observed with CHD include luxation or subluxation of the hip and osteoarthritis (degenerative joint disease). It is generally accepted and now scientifically proven that hip joint laxity (hip looseness) plays a major role in the development of osteoarthritis. phx1

Because osteoarthritis commonly causes pain and discomfort in the affected joints, the dog with CHD often has impaired mobility and a diminished quality of life. Therefore, any method that objectively measures hip joint laxity may be helpful in evaluating a dog’s risk for developing osteoarthritis and CHD. This information would assist the dog owner or breeder in deciding which animals not to breed as well as in selecting the best individual animals for breeding. Before we go further in this discussion of PennHIP, there are a few terms that are important to know. Take a look at the Definitions below and refer to them if you get confused.

Definition of terms:

Articular Cartilage, nourished by synovial fluid, is the cartilaginous surface of the end of a bone, which contributes to the function of a joint.

Osteoarthritis, Degenerative Joint Disease (DJD) is marked by degeneration or breakdown of the articular cartilage, hypertrophy of bone at the margins of the joint, and changes in the synovial membrane and joint capsule, and is accompanied by pain and stiffness.

Joint Laxity refers to the amount of looseness in a joint. Generally the more laxity the greater the potential for DJD from the trauma associated with loosely fitting joint members.

Luxation means dislocation. A luxated hip is one that has extreme laxity such that it displays dislocation of the two bones of the joint. The x-ray image at the top right of this page demonstrates a fully luxated hip on the right side of the image.

Subluxation means a partial dislocation of two joint members. The x-ray image at the top right of this page demonstrates a subluxated hip on the left side of the image.

The ventrodorsal, hip-extended radiographic view: This refers to the standard positioning of the dog on its back on the X-ray table. The radiograph is made with the beam projection from the front to the back of the dog while the rear legs are pulled symmetrically rearward. To be done properly, the view is generally done under sedation or anesthesia.

CHD in many respects has been ignored by some, underestimated by a few and fervently analyzed by many. The evidence collected over the past 65 years since Dr. Schnelle first brought it to our attention has demonstrated that the presence of hip dysplasia in a dog has definite genetic determiners. More recently, data has been presented that shows the development of joint deterioration in a dog with CHD correlates well with the degree of joint laxity present in the dog. If hip laxity is present, other environmental factors, such as nutritional, can influence the degree of expression of abnormal signs associated with Canine Hip Dysplasia. The determination of the degree of CHD in a dog, the ultimate debilitative effects of any hip joint abnormality, the heritability factors for the potential offspring and the ethics of breeding a dog with CHD all factor into making this topic somewhat complicated… as the scientists say “It’s a multi-factorial subject”. Fortunately, however, the determination of degree of joint laxity using PennHIP Distraction Index is not subjective, but an accurate quantitative measurement.

TRADITIONAL EVALUATION

The ventrodorsal (front to back), hip-extended (legs pulled straight rearward) radiographic view as approved by the American Veterinary Medical Association in 1966 has been a standard for positioning of the dog on the x-ray table. The radiograph needs to be taken with the dog under sedation or anesthesia for proper and consistent positioning. If the positioning is not correct, the asymmetrical images of the hip joints will make accurate interpretation nearly impossible. This traditional and still widely accepted method of evaluating hip structure is used by many hip screening programs throughout the world, including Orthopedic Foundation for Animal (OFA), the Institute for Genetic Disease Control in Animals (GDC) and PennHIP. The OFA system and registry has been one strategy attempting to improve the knowledge base and selection process for breeders interested in eliminating CHD from a breed. Many breeders and veterinarians agree that the incidence of CHD has noticeably decreased over the years since it was first described, partly because awareness of CHD among pet owners and breeders has reached fairly high levels. For years the OFA protocol has been the most commonly utilized method of screening and certifying dogs as having normal or dysplastic hips. Unfortunately, subjective variables can enter into the OFA evaluation process. Although preliminary radiographs can be revealing, a potential drawback with the OFA protocol is the fact that for certification and definitive evaluation a dog must be 24 months of age or older at the time the hip radiographs are taken. Additionally, occasional criticism is heard that some veterinarians unknowingly affect the evaluation of the radiograph by their subjective positioning of the dog at the time the radiographs are taken; plus individual interpretation of what is visible on the radiograph is sometimes challenged. There exists the disappointing fact that outright fraud has occurred by unscrupulous individuals who misrepresent a radiograph as being of an animal other than the one actually radiographed.

PennHIP: (University of Pennsylvania Hip Improvement Program)
And that is precisely where the PennHIP topic becomes important. Commercially available since 1993, this procedure has been and was developed as an objective method of evaluating dogs’ hip structure. It evolved as a direct result of the subjectivity factors and age constraint (maturity) limitations inherent to evaluation and certification of dogs by the OFA and other screening programs. PennHIP research published in peer reviewed journals has shown that different breeds have different susceptibility to osteoarthritis. Therefore, in PennHIP evaluations each breed is compared to its own.

PennHIP incorporates an improved method for evaluating the integrity of the canine hip. It has great potential to lower the frequency of CHD when used as a breeding selection criterion. The technique assesses the quality of the canine hip and quantitatively measures canine hip joint laxity. Originally developed in 1983 by Gail Smith, VMD, PhD and his colleagues at the University of Pennsylvania, School of Veterinary Medicine, the procedure was conceived and developed as a new scientific method for an earlier and more accurate diagnosis of CHD. Years of research conducted in Smith’s laboratory proved the diagnostic method to be capable of estimating the risk (susceptibility) for CHD in dogs as young as sixteen weeks of age.
osteoarthritis commonly causes pain and discomfort in the affected joints, the dog with CHD often has impaired mobility and a diminished quality of life. Therefore, any method that objectively measures hip joint laxity may be helpful in evaluating a dog’s risk for developing osteoarthritis and CHD. This information would assist the dog owner or breeder in deciding which animals not to breed as well as in selecting the best individual animals for breeding.

It is especially important to perform a Distraction Index (DI) on dogs that have normal appearing hips on the ventrodorsal extended view, such as appears to be the case in the image on the right. Dogs that are diagnosed as having excellent hips on the traditional VD view can actually have a huge amount of laxity. PennHIP's recommendation is to limit breeding to those dogs that have normal appearing hips on the VD hip extended view and that also have a DI at the breed's mean laxity or tighter.

The PennHIP method is a novel way to assess, measure and interpret hip joint laxity and hip conformation. Three separate radiographs are taken of a sedated or anesthetized dog…

* the distraction view

* the compression view

* the standard ventrodorsal, hip-extended view.

The distraction view and compression view are used to obtain accurate and precise numerical measurements of joint laxity and conformation. The hip-extended view is used to diagnose osteoarthritis using criteria similar to the OFA and other hip screening organizations. Precise positioning of the dog by trained certified PennHIP members is imperative and any radiographs that do not conform to prescribed positioning are rejected and must be repeated.

Interestingly, a dog's hip laxity at 16 weeks of age will be much the same at one year, two years and older. For most breeds, the PennHIP evaluation can be done as early as four months of age. Recommendations based upon peer reviewed and published research, though, state that the reliability of the PennHIP method slightly improves with age, with one year being marginally superior to six months, which in turn is marginally better than four months. The Distraction Index (DI), obtained via the distraction view radiograph, is not subjective. It is an accurate numerical measurement that has been shown to be reliable.

DISTRACTION INDEX
Also called the DI, the Distraction Index is obtained with the aid of a fulcrum so that a radiograph can be taken with the head of the femur as far out of the hip socket as possible. This distance is then measured. Hips with DIs on the distraction view that are close to 0 are considered to be tight, while DIs close to 1 are considered to be very loose. The DI is an indication of the "percent out of joint" that the femoral head is displaced from the acetabulum (socket). For example, DI=0.58 means the femoral head comes out of the joint by 58%, DI=0.75, 75% out of joint and so on. The Distraction Index of PennHIP is not subjective, but an accurate quantitative measurement that has been shown to be repeatable and reliable. A dog with a DI approaching 1 has a very high degree of predictability for developing Canine Hip Dysplasia and subsequent osteoarthritis... and should not be considered for breeding purposes.

WHO DOES PennHIP PROCEDURES
phpennhip

Only certified individuals who have undergone special training and have successfully demonstrated their expertise in the technique are permitted to perform PennHIP procedures. Since both PennHIP and OFA use the ventrodorsal, hip-extended view, your PennHIP certified veterinarian can make a copy of the hip-extended radiograph for submission to the OFA at the time your dog has the PennHIP procedure. You do not have to abandon OFA opinion nor schedule a separate appointment for an additional radiograph.

As of November 2001, there were 1,076 certified PennHIP members. 977 members are in the United States and Canada and 99 in 19 other countries. Darryl N. Biery, DVM, Professor of Radiology and a Board Certified Veterinary Radiologist at the School of Veterinary Medicine, University of Pennsylvania states, “All PennHIP certified veterinarians have passed a certification process that includes course work and quality control supervision.”

With the devastating effects of CHD, the PennHIP procedure is a welcomed addition to the opportunities dog breeders have in selecting only the best individuals for carrying on the ideal traits of each breed. That selection flexibility is enhanced by the opportunity to go beyond the qualitative description of calling a hip joint “normal” by actually applying a numerical value to “normal” and abnormal joints. That numerical value is called the Distraction Index (DI). With PennHIP the breeder can make a more appropriate choice among breeding individuals with “normal hips” by referring to the Distraction Index and selecting the best individuals in the “normal” group… the ones with the tightest hips.

The PennHIP Laboratory publishes its findings in scientific journals. Published information is disseminated to all PennHIP members; it is also shared with interested breed clubs and routinely appears in publications within the dog fancy. Will the PennHIP protocol replace the traditional OFA protocol? Only time will tell. But this newer method of evaluating dogs’ hip joints will be one more tool to improve future generations of dogs. So for all of us who love and respect canines, the PennHIP procedure should be a welcomed addition to our diagnostic and predictive treasure chest.

ADVANTAGES OF PennHIP
There are a number of advantages associated with doing the PennHIP procedure rather than the traditional method of radiography:

The PennHIP Procedure is...

* A scientifically validated method.

* Performed on dogs as young as 16 weeks of age.

* 2.5 –11 times more hip laxity is measured compared to the conventional ventrodorsal, hip-extended radiographic evaluation method. This objective measurement of hip joint laxity is critical since the amount of laxity detected has a direct relationship to the likelihood that a dog will develop arthritis (the looser the hip the greater the risk).

* PennHIP radiographic score has a higher heritability coefficient, and therefore has a greater potential to improve hips through selective breeding than the ventrodorsal, hip-extended view alone.

* Requires mandatory submission of hip films to minimize bias in database. (Even hips showing obvious dysplasia are sent in and added to the database.)

PennHIP OR OFA?
What procedure should a dog owner select when attempting to gain valid information about a dog’s hip status? I posed this question: “What is the major difference between having a dog evaluated by the OFA as opposed to having a PennHIP evaluation done?” In response Dr. Smith states, “The PennHIP radiographic evaluation has been shown scientifically to give a truer estimate of hip quality; it is more accurate, more reliable and as mentioned it can be performed as early as 16 weeks of age. The major advantage of the PennHIP method is its unique ability to identify true-normal dogs, dogs not susceptible to hip dysplasia.”

Small animal practitioner Mara DiGrazia, DVM, of New Hyde Park, N.Y., although not PennHIP certified, states her approach to the question of which procedure to use: “If a client has a young puppy that they are considering to use for breeding I would recommend the PennHIP radiographs rather than waiting for an OFA. This is because PennHIP can predict as early as 4 months of age what degree of hip dysplasia the dog may develop. Early OFA radiographs may not reveal the same degree of laxity in the joint. Early identification of hip deformity can make a world of difference to the dog’s future life. The PennHIP procedure can bring about a timely spay or neuter if the dog has been found to be unworthy of breeding due to poor hip conformation. The dog’s lifestyle can then conform to its needs as a pet rather than as a working or breeding dog.“

http://www.thepetcenter.com

sole property of ThePetCenter.com.
Any copying or reprinting of this material may be done only with verifiable permission.

mailto:Contact Permission@petfooddirect.com for details

***********************

PennHIP: Misconceptions and Misinformation

A 1998 magazine, newsletter, and website article by Fred Lanting

Breeders have a very interesting tool these days in the Internet and/or e-mail. Information gets out much faster than print media can disseminate it. Among the accepted characteristics of such transmission are slightly higher "I.Q." (inaccuracy quotients) and emotion levels. It seems that these minor failings are forgiven in the informal tone of this medium.

However, it still behooves anyone doing the work of a journalist, commentator, or editor to be as accurate as possible, for people tend to believe anything they see "in print". Recently, there have been lively discussions on at least one list or website, excerpts of which have been circulated to others. These deal with the latest development in diagnostic-predictive techniques, and unfortunately fanciers have taken sides based on less than complete information.

Understandable; I found in 35 years in chemical marketing that people make decisions based not so much on logic or reasoning, as much as on emotional leanings.

Here are some recent website quotes I've been given, and my responses. I encourage you readers to make yourselves available to one of my lectures.

Better yet, to schedule one. "Have slides, will travel". E-mail me at mailto:Mr.GSD@juno.com for details. First, the quotes and misinformation, then my answers.

Quote 1.: "(Some people) bought a dog and it turned out to be dysplastic at 2 years, when her (OFA) prelim at 10 months looked excellent. This may be an argument for using PennHIP, said to be more predictive. In the PennHIP X-rays, more laxity can be measured." This lister tries to be cautious yet seems to lean toward confidence in the newer (a decade now) method of screening dysplasia at younger ages.

Quote 2.: "... a bummer when that happens. However, studies have not shown PennHIP to be more reliable in predicting HD than OFA. In fact they show the opposite (JAVMA volume 21 #9 Nov 1, 1997); in referring to OFA: 'The study showed that a preliminary evaluation of Excellent was 100% reliable; a preliminary evaluation of Good was 97.9% reliable; a preliminary evaluation of Fair was 76.9% reliable...'.

Also, (Am J Vet Res 1993; 54: pp.1021 - 1042) in referring to PennHIP:

'12% of the dogs evaluated as normal at 4 months of age by the PennHIP method were later determined to have degenerative joint disease. 48% of the dogs evaluated as abnormal at 4 months of age, 57% evaluated as abnormal at 6 months of age and 38% evaluated as abnormal at 12 months of age by the PennHIP method did not have evidence of degenerative joint disease at 24 months of age'. A second study on the PennHIP method (Am J Vet Res; 1993; 54: pp.1990-1999) concludes that while a distraction index less than 0.4 is 88% reliable for predicting normal hips, a distraction index of greater than 0.4 is only 57% reliable for predicting CHD. While no method would be 100% reliable, it would appear that the OFA method is more reliable at early prediction of CHD. What bothers me most about the PennHIP method is the very high percentage (38 - 57%) of those dogs evaluated early where they predict CHD will develop, but it doesn't.

Thus, if you use the PennHIP method for early evaluation, you have a very good chance of eliminating a non-dysplastic dog from your breeding program due to less than accurate results."

MY RESPONSE:
By the way, while the veterinary community largely uses the abbreviation CHD for Canine Hip Dysplasia, I use the lay practice of referring to it as HD, since the context is always clear that we are talking about the disease in dogs, not in humans or other animals. Now, as to the quote #2 above: far from concluding that OFA is more reliable and accurate, the cited journal references, which I have on the desk before me, can only logically lead to the realization that the opposite is true, except for the Nov.1st, 1997 reference written by Al Corley and Greg Keller of the OFA. To be fair, one must also read at the same sitting, the letter to the editor on page 487 in JAVMA's vol. 212, #4, Feb. 15, 1998 which effectively refutes those OFA conclusions. OFA statistics are skewed because not all films are sent in; PennHIP requires ALL films, whether showing horrible hips or not, be sent in and entered into the database. The OFA article did not let readers know that apples were being compared to oranges --- that the presumably higher rate of false positives PennHIP reports is a result of different definitions. OFA says a dog is dysplastic if it has loose hip joints, signs of arthritic changes or wear, or both. PennHIP diagnoses frank HD on the basis of DJD (degenerative joint disease... bony changes and remodelling). If they had included the lax-hip dogs not showing such changes, the false positive rates would be much lower. The PennHIP evaluation not only reports as dysplastic those with obvious bone and cartilage abnormalities, but also gives an idea of the relative risk of the particular dog developing such radiographic signs later. The dog whose hip joint's femoral head looks tight and round on the OFA film but shows considerable laxity on the PennHIP view is said by the latter group to be at risk for later DJD. Which information would you want to have?

Remember, the traditional position advocated by AVMA and OFA (as well as almost all other hip schemes of the past 35 years) is the leg-extended (hip-extended) one in which the ligaments of the hip joint capsule are wound tight like the rubber band in those toy aeroplanes we old fogies used to play with as kids. This tends to present an artificially tight appearance to all but the worst hips, and is certainly not representative of the forces at work in the standing or walking/trotting dog. The PennHIP scheme utilizes this hip-extended view in order to best see some features that might show DJD; by the way, if you want an OFA reading, the vet need only put two films into the cassette when taking this picture. The view with the dog's legs flexed in a position like standing, but upside down, mimics actual forces. And when the hip joints are stressed in the distraction view (femurs and femoral heads pushed away from each other and the acetabulums) and then the difference in displacement measured from the picture given when they are pressed into the sockets, why then you have a numerical, objective value: something you can use to compare with others of the same breed, for example.

Now, let's look at the predictive value of OFA's preliminary evaluations, and I won't go at length into why suddenly these are supposed to be so accurate, when in 1972 OFA led the way to a 24-month minimum for certification because of the inaccuracy of early diagnoses. Let's assume that only the very worst hips will show bony changes, and that the youngsters now being "prelim'ed" are judged primarily on laxity. The OFA is happy to predict, on the basis of very tight joints IN THE HIP-EXTENDED VIEW at a young age, that such an excellent appearance will continue to look good at 2 years (minimum age at which to certify). But remember, the view at 2 years is going to be the same type, that of an artificially wound up joint capsule. Surely, then, one would expect fairly good agreement between the pictures at these two ages, especially if rated "Excellent" in the AVMA position. However, if one applies the more stringent evaluation protocols of the PennHIP method at the older age, one finds a disturbing number of "OFA-normals" are indeed not normal in any sense that you and I would consider so, such as compared with the mean or average in the breed. Even an unacceptably high number of OFA-Excellents at 2 years will show up in the PennHIP view to have worse hips than would otherwise be suspected. If you want to know if a bridge can bear a load of 10 tons, you shouldn't expect to run a meaningful test by driving your half ton pickup over it. The dog also should be evaluated in the strictest method in order to tell if the reading of "excellent" has any validity. Otherwise, the breeder or the person driving a big truck over a bridge may have a false sense of security.

Those who look into professional journal articles should perhaps ask, "Where are the data showing a link between OFA-defined laxity and later DJD?" and "Where are the data on dogs diagnosed as dysplastic (based on laxity at 24 months) but who never developed the bony changes?"

Since there is no such set of statistics, one must conclude that hip-extended radiographic diagnosis (alone), even at 24 months, is not "reliable" as the OFA's JAVMA article proposes, but highly unreliable, or at best, unknown. Are you as a breeder satisfied with repeatability (unfortunately described as reliability)? Suppose you were William Tell's son, and you knew that your dad could shoot a dozen arrows at the apple balanced on your head, with repeatability as to where each would go --- would you be blithely unaffected by the concept that his reliability (accuracy) might not be as good as his repeatability?

You would not want even the first arrow to fly, would you? Diagnosing HD is not as threatening as that, but I for one would want the most accurate as well as the most reliably repeatable evaluations of my breeding stock's hips.

DJD appears in some individual dogs and in some breeds at later ages than in others. The breeder wants to know as early as possible, what the likelihood is that his dogs might develop DJD, and therefore wants some sort of "marker" or predictive evaluation before he sells or breeds. The panacea of gene markers (looking at DNA and finding all the sequences that cause HD) is not practical in our lifetimes (or at least not in our current dogs' lifetimes). If anybody even were to come up with cheap testing of such polygenic traits, this approach is still decades away.

The OFA study reported in that JAVMA article did not include in its references any longitudinal studies to refer the reader to, even though a year or so earlier such a report by Banfield, Bartels, Hudson, et al showed almost no difference in dogs predicted to develop degenerative changes and those described as having normal hips, using the OFA-style methods. The 40 dogs described as "normal" at 2 years of age all had some "minimal or mild degenerative changes" by 9 years of age, and those 22 dogs diagnosed as dysplastic (lax joints in the hip-extended view) at 2 years had the same mild or minimal changes. Why wasn't this study included? Does it give you a warm feeling that you are using the latest and most accurate diagnostic techniques by banking on the OFA readings?

We shouldn't worry so much about false positives (a red flag that a dog might become dysplastic, but doesn't) as we should about false negatives (the dog is evaluated as normal, and later proves to be chock-full of "bad genes" that his offspring inherit).

We would rather cull from the breed an occasional good dog (there are many ready to take his place) than let some covert fifth columnist into the ranks to poison or sabotage the gene pool. In the OFA system there are false negative rates of about 83% in 6-month-old German Shepherds, but in the PennHIP scheme, the rate is only 12% in 4-month-old dogs and 0% at 6 months (as compared to the readings at 24 months). The writer who complains about this 12% fails to acknowledge that using the OFA approach on 4-month pups gave a false negative rate of 24%, double that of the PennHIP compression-distraction method. Even at 6 and 12 months, the OFA-type predictive tests gave false negatives of 15% and 12% and the PennHIP stress-radiographic method showed zero false negatives for 6- and 12-month old dogs.

To rest one's case on the above mentioned "48% of the dogs evaluated as abnormal at 4 months of age, 57% evaluated as abnormal at 6 months of age and 38% evaluated as abnormal at 12 months of age by the PennHIP method" as not having "evidence of degenerative joint disease" is to rest on the false positives. What of those dogs that did not have DJD at 2 years of age, but more laxity than the average in their breed?

Are you satisfied that they have as few bad genes as do the dogs that were identified early as having a very low DI (distraction index) and still do not have DJD in old age? The PennHIP method is a far better revealer of genotype, and thus predictor of eventual DJD, in the individual and its progeny.

It should not be surprising to anyone that the looser the hips, the less accurate that a prediction of a specific grade or severity might be. HD is a developmental (DJD might not show up right away), progressive (it'll eventually be worse), multifactorial (environment has a part to play in the expression of the bad genes) disorder. Some dogs will get worse than others even with the same DI at a young age. A DI of 0.4 is not all that bad, nor all that good. You can pretty much guarantee your buyers that the pup you sell them with a 0.3 will never have DJD (HD), but you lose credibility with such a guarantee as that index creeps higher and higher. You can think of an index of 0.4 as being "40% out of the socket" if you want to oversimplify the picture, since the readings runs from a hypothetical 0 (zero would mean no ability to move in the socket) to a full luxation of 100% out of the socket, or DI of 1.0 (and of course in the worst cases, the number can be over one, but those dogs will have bad bone changes, too, so it doesn't take a rocket scientist to see they are dysplastic). In many breeds, the mean or average laxity is around 0.4 and it is worse in many other breeds. Some breeds can tolerate looser hips than a GSD and have less development of arthritic degeneration in maturity. The person who worried about the "38 - 57% of those dogs evaluated early where they predict CHD will develop, but doesn't..." isn't adding "at two years of age", and again ignores the much worse situation where at least an equally high percentage of OFA-normal dogs might develop late onset DJD and/or pass on many bad genes to offspring. There is very good reason to presume that dogs that have no signs of DJD but have an index higher than the mean for their breed "represent a carrier state of the disease", as mentioned in the second Am J Vet Res citation above. In other words, it is a clearer picture of the genotype than the OFA approach gives.

Man has advanced over his prehistoric precedents by using more tools, and we should progress in use of modern tools regarding HD as we have from the Neandertal to the Stone Age to the Bronze Age to the Machine Age, and to the Computer Age. PennHIP is such an advanced tool for the serious breeder.

The inescapable conclusions are that:

1. Tighter Is better;

2. Position and technique (better tools) can discover covert laxity;

3. PennHIP is more accurate as well as reliable and repeatable.

Most of the people on these Internet chat rooms and e-mail lists are not "professional people" by which in this context is meant trained veterinarians. Thus, it is natural that few would realize until pointed out to them, that there are significant differences between types of articles they read. Something that appears in a medical journal such as JAVMA are closely examined in a process called "peer review" before being edited and published. Both accuracy and logical reasoning are required, in addition to sound references and proper controls and procedures in the reported experimental work. On the other hand, articles that appear in newsletters, flyers, press or publicity releases, brochures, and the like, are not subject to such hurdles and requirements. The OFA press release that was carried by a number of breed magazines such as the Australian Cattle Dog publication in mid-1998 was a rather strongly biased advertisement for OFA business --- absolutely nothing wrong with that approach, by the way. The AVMA Journal version published Nov. 1, 1997 was what remained after the review process removed all the unsubstantiated claims. Now, such claims may be valid; it's just that in this case, they were not subjected to protocols regarding scientific method and therefore the "commercial version" may have been misinterpreted by some as having the weight of the reviewed version.

The optimist in me sees the day when OFA leadership will have to admit the superiority of new tools, adopt the PennHIP approach, and report such data for the benefit of the breeder. The pessimist in me wonders if the parties can put personalities aside and concentrate on science, and if I'll live long enough to see this happen.

Fred Lanting, Canine Consulting: mailto:Mr.GSD@hiwaay.net 3565 Parches Cove Rd, Union Grove AL 35175-8422
Lectures & Seminars on Orthopedic Disorders, Gait-&-Structure, Etc.

For reprint rights, contact the author mailto:Mr.GSD@hiwaay.net

***********************