Hip Dysplasia in Cavalier King Charles Spaniels
-
Symptoms
- Diagnosis
- - OFA Evaluation
- - PennHIP Method
- - BVA/KC Scheme
- Treatment
- Breeders' Responsibilities
- Related Links
- Veterinary Resources
Hip Dysplasia (HD) is a common*, heritable disease in cavalier King Charles spaniels which can cause the dogs terrible pain and debilitation. HD is the abnormal development of the hip, which can produce various degrees of arthritis (which also may be called degenerative joint disease, arthrosis, or osteoarthrosis).
* Estimates of affected CKCSs range from 12.4% to 33%. See details below.
Symptoms
It is not predictable as to when or even if a dog with HD will start showing signs of lameness due to pain. There are many environmental factors, including caloric intake and the level of exercise, which can affect the severity of pain and lameness. Many dysplastic dogs with severe HD can run, jump, and play as if nothing is wrong, and other dogs with barely any HD x-ray indications are severely lame.
Diagnosis
The only way to accurately diagnose HD is by radiography ( x-ray). Hip dysplasia is a developmental disease, meaning that it is not present at birth, but develops with age; it normally does not appear at all in x-rays of puppies or young cavaliers.
-- OFA evaluation
The
Orthopedic Foundation for Animals
(OFA) provides x-ray evaluations by panels of board certified veterinary
radiologists. The PennHip
method of hip joint analysis is an alternative means of diagnosing HD, also by
x-ray.
According to OFA's statistics, 12.4% of all cavaliers are afflicted with hip dysplasia. However, the vast majority of cavalier breeders do not submit to OFA any x-rays of their breeding stock which show obviously dysplastic hips.* Therefore, OFA's statistics do not accurately reflect the incidence of HD in cavaliers. For example, only 5,896 cavaliers have been evaluated by OFA in the 37 years from 1974 through 2011 (only 370 in 2011). Considering that in 2008 alone, the AKC registered over 8,000 cavaliers, the OFA data base is woefully short. This indicates a major lack of interest by most all CKCS breeders in obtaining objective, expert evaluations of their dogs' hips.
*The Cavalier King Charles Spaniel Club,USA makes this comment on its website about the lack of submission of x-rays to OFA: "Since x-ray results are not always sent to OFA by breeders whose vets consider them dysplastic, this number is not exact and one can assume that 12.6% is a low figure."
OFA requires that dogs be at least 24 months
old when x-rayed in order to qualify for a permanent OFA evaluation. OFA
evaluates the x-rays by assigning a classification to each dog, from excellent,
good, fair, borderline, mild, moderate, to severe. Ideally, breeders should
consider x-raying their breeding stock again annually thereafter, as hip
dysplasia has been found to be a progressive genetic disorder which results in
deterioration of the hip joints after age two years.
It is believed by veterinary specialists in the field of hip dysplasia that the true incidence of HD in the cavalier King Charles spaniel probably is as much as two to three times as high as those statistics would indicate, meaning from 24% to 36% of all cavaliers, or as many as one third or more of all of the dogs in the breed.* Even higher percentages of cavaliers have been reported in recent studies of dogs requiring surgical hip procedures. See Veterinary Resources below. By comparison, OFA's current statistics show that 66% of pugs had dysplastic hips, 44.8% of Clumber spaniels, 30.4% of French bulldogs, and 19.7% of golden retrievers.
* A 2010 study of the PennHIP method, described below, also suggests that OFA scoring can underestimate the true incidence of hip dysplasia in dogs.
-- PennHIP method
The PennHip method was developed in 1983 by Dr. Gail
K. Smith, right, an orthopedic
surgeon at the University of Pennsylvania School of Veterinary Medicine.
It measures hip joint laxity (looseness), which is the primary cause of
degenerative joint disease. The Distraction Index (DI) used in the PennHip
method is a measurement of passive hip laxity, the degree of looseness of the
hip joint when the dog's hips are completely relaxed. Dogs with a DI of 0.3 have
tighter hips and are less likely to develop hip dysplasia, and dogs with looser
hips and DI values approaching 0.7 or more are at greater risk.
In a 2010 study
conducted by Dr. Smith and others, they compared OFA and PennHIP evaluation
results for 439 dogs from 1987 through 2008. The results showed that high
percentages of dogs judged by OFA to be phenotypically normal nevertheless had
clinically important passive hip joint laxity as determined by PennHIP's
distraction radiography. The study concluded that dogs judged as "normal" by OFA
can have clinically important passive hip joint laxity as determined by the
PennHIP method. The results suggest that OFA scoring can underestimate
susceptibility to osteoarthritis in dogs, which may impede progress in reducing
or eliminating hip dysplasia through breeding.
You may contact Dr. Gail Smith at email smithgk@vet.upenn.edu
-- BVC/KC hip dysplasia scheme
The British Veterinary Association (BVA) and the UK's Kennel Club
(KC) have
instituted a hip dysplasia x-ray scheme for all breeds, which is similar to
those of OFA and PennHIP. Details may be found at
BVA's
website here. Statistics for cavaliers under the BVA/KC hip scheme indicate
that, as of October 2010, x-rays of only 270 CKCSs (compared to, e.g., over
70,000 Labrador retrievers) have been submitted for
review under the scheme. Analysis of those x-rays show that the ratings of the
UK
cavaliers' hips ranged from "0" (no dysplasia) to "93" (severe dysplasia).
See the
BVA/KC statistics here.
Treatment
Initial treatment is aimed at relieving pain and improving function with medication for the treatment of degenerative joint disease. If pain cannot be controlled there are expensive surgical procedures which may relieve pain and improve function in some dogs.
Stem cell therapy is being used on cavaliers by some practitioners, with reportedly successful results. See, e.g., this 2010 clinical report.
In a 2011 report, a team of Irish veterinary surgeons repaired the hips of 70 dogs with hip dysplasia (seven were CKCSs), using a "modified transarticular pinning technique". In a 2012 report, US surgeons, including Dr. Dominic Marino, reported on micro total hip prosthesis of 41 dogs, including six cavalier King Charles spaniels. In another 2012 report, the same US surgical team reviewed the outcomes of nano total hip replacement (NanoTHR) in twelve dogs, including a cavalier.
Breeders' Responsibilities
The Canine Inherited Disorders Database recommends that breeders breed only dogs that have disease-free joints and that come from ancestors with disease-free joints. The Canine Inherited Disorders Database further recommends not breeding any cavaliers whose offspring have hip dysplasia (dogs with hip dysplasia can produce normal offspring, and normal-appearing dogs can produce offspring with hip dysplasia).
The general principles recommended by OFA for breeding away from HD are:
1) Breed only normal dogs (meaning, not dysplastic) to normal dogs.
2) The normal dogs should come from normal parents and grandparents.
3) The normal dogs should have over seventy-five percent normal siblings.
4) A dog with excellent hips from a litter having more than twenty-five percent dysplastic pups is a worse breeding choice than a dog with fair hips from a litter experiencing less than twenty-five percent dysplasia.
5) Choose replacement dams that have better hips than their parents and the breed average.
Breeders should have their breeding cavaliers' hips x-rayed after age two years and have the x-rays evaluated by OFA before considering the dogs for breeding. Ideally, breeders should consider x-raying their breeding stock again annually thereafter, as hip dysplasia has been found to be a progressive genetic disorder which results in deterioration of the hip joints after age two years.
The Cavalier King Charles Spaniel Club, USA recommends that, prior to breeding any cavalier, the dog have a passing grade from an x-ray for hip dysplasia submitted to the OFA.
The Canine Health Information Center (CHIC) is a centralized canine health database sponsored by the AKC/Canine Health Foundation (AKC/CHF) and OFA. The CHIC, working with participating parent clubs, provides a resource for breeders and owners of purebred dogs to research and maintain information on the health issues prevalent in specific breeds.
AKC's national breed clubs establish the breed specific testing protocols. Dogs complying with the breed specific testing requirements are issued CHIC numbers. The ACKCSC requires that, to qualify for CHIC certification, cavaliers must be screened for hip dysplasia, using the OFA, PennHIP, or OVC protocol.
Related Links
The Orthopedic Foundation for
Animals (OFA)
PennHIP
British Veterinary Association
Veterinary Resources
Control of Canine Genetic Diseases. Padgett, G.A., Howell Book House 1998, pp. 198-199, 245.
Evaluation of the relationship between Orthopedic Foundation for Animals' hip joint scores and PennHIP distraction index values in dogs. Michelle Y. Powers, Georga T. Karbe, Thomas P. Gregor, Pamela McKelvie, William T. N. Culp, Hilary H. Fordyce, and Gail K. Smith. JAVMA Sept 2010; 237(5):532-541. Quote: "Objective—To compare 2 screening methods for detecting evidence of hip dysplasia (Orthopedic Foundation for Animals [OFA] and PennHIP) in dogs. 439 dogs ≥ 24 months of age [Cavalier King Charles spaniel included] that received routine hip joint screening from June 1987 through July 2008. Dogs were sedated, and PennHIP radiography was performed (hip joint– extended [HE], compression, and distraction radiographic views). The HE radiographic view was submitted for OFA evaluation. A copy of the HE radiographic view plus the compression and distraction radiographic views were submitted for routine PennHIP evaluation, including quantification of hip joint laxity via the distraction index (DI). Results: 14% (60/439) of dogs had hip joints scored as excellent by OFA standards; however, 52% (31/60) of those had a DI ≥ 0.30 (range, 0.14 to 0.61). Eighty-two percent of (183/223) dogs with OFA-rated good hip joints had a DI ≥ 0.30 (range, 0.10 to 0.77), and 94% (79/84) of dogs with OFA-rated fair hip joints had a DI ≥ 0.30 (range, 0.14 to 0.77). Of all dogs with fair to excellent hip joints by OFA standards, 80% (293/367) had a DI ≥ 0.30. All dogs with OFA-rated borderline hip joints or mild, moderate, or severe hip dysplasia had a DI ≥ 0.30 (range, 0.30 to 0.83). Conclusion and Clinical Relevance: Dogs judged as phenotypically normal by the OFA harbored clinically important passive hip joint laxity as determined via distraction radiography. Results suggested that OFA scoring of HE radiographs underestimated susceptibility to osteoarthritis in dogs, which may impede progress in reducing or eliminating hip dysplasia through breeding."
Treatment of 70 dogs with traumatic hip luxation using a modified transarticular pinning technique. W. McCartney, K. Kiss, F. McGovern. Vet.Rec. Mar 2011; 168(13):355. "Luxation of the hip is the most common joint luxation in dogs. Treatment options are based on closed reduction, or surgical reduction and stabilisation using intra-articular or extra-articular methods. The intra-articular techniques include toggle pin variations or transarticular pinning, whereas the extra-articular techniques include de Vita pinning and extracapsular prosthesis. This short communication describes an analysis of 70 cases of traumatic hip luxation in dogs treated with a modified transarticular pinning technique. Seventy dogs were operated on for hip luxation between 2003 and 2009. The predominant breeds were labrador retriever (13), collie (10), golden retriever (nine), German shepherd dog (eight), Cavalier King Charles spaniel (CKCS) (seven) and mixed breed (12). The remaining 11 dogs were poodles (two), Staffordshire bull terriers... A retrospective analysis of hip luxation case details was undertaken in conjunction with a telephone questionnaire survey of the owners; all 70 dogs had sufficient data for analysis. Dogs with underlying hip dysplasia or osteoarthritis did not have transarticular pinning performed as a treatment for hip luxation. Only cases in which an outcome assessment had been made using the owner questionnaire more than six months postoperatively were included. Two questions were asked in the questionnaire. For the first, ‘Is your dog stiff or lame at any time and if so can you grade it as frequent, intermittent or never?’, frequent was described as more than three times a day, intermittent as up to three times a week and never as no lameness or stiffness at anytime. For the second, ‘Are you satisfied with the outcome?’, there were two possible answers – ‘satisfied’ and ‘not satisfied’. On the basis of the owner's repsonses, the outcome was graded as failed, poor, good or excellent. The outcome grading was classified as excellent if a dog had no complications and was not stiff or lame at any time, good if the dog was only intermittently stiff or lame up to three times a week, poor if there was frequent (daily) lameness or stiffness, and failed if there were any serious complications. There were 33 females and 37 males, and the age range was six months to 11 years."
Micro Total Hip Replacement in Dogs and Cats. Dominic J Marino, Shadi J Ireifej DVM, Catherine A Loughin. Vet. Sur. Jan 2012; 41(1):121-129. Quote: "Objective: To describe the surgical technique using power-assisted femoral preparation and clinical outcome in 41 dogs and 2 cats surgically treated with the micro total hip prosthesis. Animals: Dogs (n = 41[cavalier King Charles spaniels = 6]) and 2 cats. Results: Six dogs had staged bilateral MicroTHR, 35 dogs and 2 cats had unilateral MicroTHR. Median body weight was 8.2 kg (range, 2.1–14.2 kg) whereas for those that had complications (fracture or luxation) it was 8.6 kg (range, 6.6–14.1 kg). Median operative time was 71 minutes (range, 55–105 minutes). Complications included luxations (5 of 49; 10%) and femoral fracture (1; 2%). Lameness grades assigned at the 3-month recheck examination: 39 (80%) animals were grade 1, 6 (12%) were grade 2, and 4 (8%) were grade 3. Forty-five animals (92%) had good or excellent results. Conclusions: MicroTHR is a practical and effective surgery in small breed dogs and cats with coxofemoral disease."
Nano Total Hip Replacement in 12 Dogs. Shadi Ireifej, Dominic Marino, Catherine Loughin. Vet. Sur. Jan 2012; 41(1):130-135. Quote: "Objective: To determine the short-term clinical outcome of nano total hip replacement (NanoTHR) in dogs. Results: Breeds were Yorkshire Terriers (n = 6), Toy Poodles (2), with 1 each of Maltese, Pomeranian, Cavalier King Charles Spaniel, and Shih-Tzu. Median body was 4.87 kg (range, 2.5–5.90 kg) and median age, 35.75 months (range, 12–144 months). Radiographs were taken in 4 dogs at 12 days (n = 2), 14 days (1), and 30 days (1) after surgery because of presentation for an acute grade 5 lameness. Three dogs had femoral fractures distal to the femoral implant tip and 1 dog displaced the acetabular implant medially. After revision surgery, all femoral fractures were assessed as healed with intact plate fixation. The dog with the medially displaced acetabular component responded to conservative management including strict confinement and analgesic administration. Eight dogs (58%) were assigned a grade 1 lameness and 4 dogs were grade 2 (33%) at 12-week examination. The 3 dogs with grade 5 lameness scores found to have femoral fractures within 1 month after surgery, subsequently improved to grade 1 (n = 1) and 2 (2) 12 weeks after revision surgery. The dog with medial acetabular displacement improved to a grade 2 lameness 12 weeks after conservative management. Conclusions: Although all 12 dogs had good-to-excellent outcomes, 33% experienced significant complications associated with the technique. As improvements in instrumentation and refinements in the technique are developed, NanoTHR can be considered an alternative to the femoral head and neck ostectomy (FHO) or medical management of coxofemoral disease for toy breed dogs. Further studies with a larger number of dogs and longer follow-up times are required."
