Estimates of prevalence of hip dysplasia in Golden Retrievers and Rottweilers and the influence of bias on published prevalence figures

Comparison of the distraction index and Norberg angle with radiographic grading of canine hip dysplasia

The Orthopedic Foundation for Animals (OFA) radiographic grading system stands as a well-established benchmark for categorizing hip dysplasia in canines. Although more objective techniques to quantify early hip laxity in young dogs, such as the Norberg angle (NA) and distraction index (DI), have been documented, there is a scarcity of published studies that directly compare these radiographic measures. The primary objectives of this prospective, analytical study were to assess and compare the NA and DI measures with OFA grades within a cohort of dogs. Thirty dogs (57 hip joints) were evaluated, with a mean age of 5.4 ± 2.9 years and a mean body weight of 34.3 ± 7.1 kg. The discriminative power of hip dysplasia for DI and NA used OFA as a reference were compared by multivariate discriminant analysis test. Using the DI (≤0.3) 12 joints were classified as normal, using NA (≥105°) 24 joints and using OFA (≤3) 29. When comparing the discriminant power of NA with OFA resulting similar (P = .8324) with correct classifications of 81% using cross validation, however, the discriminant power of dysplasia of the DI resulted significantly greater (P = .0034) than OFA with correct classifications of only 59% using cross-validation, consequently it was possible determined that of 29 patients with OFA ≤ 3, 20 had DI > 0.3. These findings demonstrated that phenotypic healthy dogs according to OFA grading can present passive hip joint laxity, as demonstrated by radiographic evaluation with distraction. Furthermore, DI can contribute to the screening of CHD when evaluated in conjunction with OFA grading.

Ethical Concerns about Fashionable Dog Breeding

The historical relationship between humans and dogs has involved selective breeding for various purposes, such as hunting, guarding, and service roles. However, over time, there has been a shift in preferences from functionality to aesthetics, which has influenced the diverse sizes, shapes, and coats of dog breeds. This review looks at fashionable dog breeding and questions the ethics of prioritising looks over health and behaviour. It aims to alert potential owners, breeders, and regulators to the importance of considering a dog's overall well-being, not just its appearance, which has resulted in fad breeding, leading to genetic disorders, health issues, and a loss of biodiversity. Ethical concerns arise from breeding brachycephalic breeds with respiratory conditions, inbreeding causing inherited disorders, and overbreeding popular breeds while shelter dogs remain unadopted. Additionally, the impact of cosmetic surgeries on popular dog breeds, as well as the neglect of behavioural traits in favour of physical characteristics and strict breeding practices are also considered. The current breeding model can have a negative impact on the emotional and cognitive well-being of dogs, resulting in issues such as aggression, anxiety, and other behavioural problems that can significantly reduce their overall quality of life. Unregulated breeding practices and the demand for rare breeds can lead to illegal breeding, compromising animal welfare. Prospective owners, veterinarians, kennel clubs, and legislators all need to play a responsible role in protecting animals.

Radiographic Diagnosis of Hip Laxity in Rottweilers: Interobserver Agreement at Eight- and Twelve-Months of Age

Hip laxity is one of the predisposing factors of canine hip dysplasia. The early diagnosis of hip laxity allows veterinarians to prevent the participation of dysplastic dogs in breeding programs, which could lower the disease's prevalence due to its genetic background. Furthermore, it allows them to plan preventive/therapeutic procedures for mild/near-normal hips to reduce the symptoms of the disease at older ages. A reliable screening program must be repeatable and reproducible, and intra- and inter-observer studies can help us to determine the best methods. In this study, we aimed to evaluate the radiographic parameters used for the early diagnosis of hip dysplasia in Rottweilers at 8 and 12 months of age with five observers to assess the interobserver agreements. According to our findings, there were high interobserver agreements at both ages for the quantitative values, such as the center edge angle (CEA), dorsal acetabular rim slope (DARS), distraction index (DI), and Norberg angle (NA), whereas we recorded from poor to moderate agreements for the qualitative values, such as the grading of the dorsal acetabular rim (GDAR), grading of the degenerative joint disease (GDJD), location of the center of the femoral head (LCFH), and sclerosis of the cranial acetabular rim (SCAR).

Enflicoxib for canine osteoarthritis: A randomized, blind, multicentre, non-inferiority clinical trial compared to mavacoxib

BACKGROUND

This prospective, multisite, blinded, randomized, non-inferiority clinical study aimed to confirm the efficacy and safety of enflicoxib in the treatment of pain and inflammation associated with canine osteoarthritis. A total of 180 dogs were randomized to receive enflicoxib (n = 78), mavacoxib (n = 80) or placebo (n = 22). Dogs underwent veterinary assessments from day 0 to day 42 using a clinical sum score (CSS). Efficacy was also assessed by the owners using the Canine Brief Pain Inventory (CBPI). The primary efficacy endpoint was the overall CSS from day 0 to day 42.

RESULTS

The overall CSS expressed as area under the curve demonstrated non-inferiority of enflicoxib compared to mavacoxib, and both showed superiority over placebo. At the end of the study, average CSS, and the percentage of CSS responders for enflicoxib (3.64 and 74%) and mavacoxib (4.49 and 68%), was superior to placebo (7.15 and 29%). A faster onset of action was observed for enflicoxib as superiority over placebo was evidenced from the first efficacy assessment (day 7) onwards for both parameters, whereas mavacoxib was only significantly different from day 14 onwards. According to the owner assessment, the percentage of CBPI responders was 90%, 79%, and 43% for dogs treated with enflicoxib, mavacoxib and placebo, respectively, and superiority over placebo was demonstrated for both active treatments. In all secondary parameters, non-inferiority of enflicoxib versus mavacoxib was confirmed. The dog's quality of life improved in all groups, but only enflicoxib showed superiority versus placebo. When assessing severely affected dogs only, results were similar, thus confirming the efficacy of enflicoxib in all stages of canine OA. There were no differences between groups in the frequency of adverse events, which were most frequently mild affecting the gastrointestinal tract and recovered without treatment.

CONCLUSIONS

Enflicoxib is efficacious and safe for the treatment of pain and inflammation in any stage of canine osteoarthritis with a faster onset of action compared to mavacoxib.

Long-term intake of Lilium lancifolium mitigated osteoarthritic effects by suppressing inflammatory cytokines in a dog model

Background and Aim: Osteoarthritis (OA) is a chronic, painful, degenerative inflammatory disease of the synovial joints. Regular use of nonsteroidal anti-inflammatory drugs to decrease OA pain can have severe side effects, such as gastric irritation, ulcers, and heart problems. Natural products are extensively used to minimize OA-associated pain and inflammatory reactions. Lilium lancifolium is commonly used to alleviate several diseases through its anti-inflammatory effects. This study examined the impact of L. lancifolium extract on alleviating pain and inflammation associated with articular cartilage damage. Materials and Methods: Hydro-ethanol extracts of the L. lancifolium bulb were used. The experimental animals (adult beagle dogs) were divided into four groups: sham, which received neither treatment nor surgery; placebo, which received an empty gelatin capsule; glucosamine, which received glutamine (60 mg/kg); and L. lancifolium, which received an L. lancifolium extract-filled (60 mg/kg) gelatin capsule for 8 weeks. OA was induced by an expert orthopedic surgeon in 2-year-old dogs through resection of cranial cruciate ligament and lateral collateral ligament. Inflammatory cytokines, enzymes, lameness score, radiology, and histological changes were assessed. Results: Our experiments showed that long-term oral therapy with L. lancifolium alleviated inflammation and increased histological damage. L. lancifolium treatment effectively reduced cytokines, such as interleukin-6, metalloproteinase-9, leukotriene-4, prostaglandin, and cyclo-oxygenase in dogs with OA, suggesting the potential to minimize inflammatory reactions in OA. L. lancifolium showed anti-inflammatory qualities in dogs with OA. This effect was comparable with that of glucosamine OA treatment. Conclusion: L. lancifolium supplementation represents a possible therapeutic and management option in this model of OA.

In Vitro Characterization of Canine Microfragmented Adipose Tissue Non-Enzymatically Extracted from the Thigh and Lumbar Regions

Simple Summary

Mesenchymal stem cells are located in bone marrow, adipose tissue, synovial membrane, and muscular tissue. They have an immunosuppressive, anti-inflammatory, and antifibrotic effect. Tissue engineering considers the usage of mesenchymal stem cells as a possible option for regenerating tissues, with respect to bone and cartilage, due to their ability to differentiate into multiple cytotypes (including chondrocytes and osteoblasts). Herein, we characterize a non-invasive solution based on Rigenera^® technology, a mechanical disaggregation method able to produce autologous adipose tissue-derived micrografts which are analogous to adipose-derived stem cells.

Abstract

Within the adult canine population, disabilities and symptoms including joint pain and functional impairment are commonly observed in articular cartilage lesions and present a challenging feat in the operating room. Clinical settings require less invasive and more minimally manipulated measures facilitated by innovative and advanced technology. Mesenchymal stem cells have recently been proposed and, furthermore, autologous adipose tissue administration via injection has emerged as a new albeit somewhat controversial therapeutic tool. The purpose of this study is to characterize canine autologous micro-fragmented adipose tissue (micrografts) by mechanical approach without substantial manipulations. Adipose tissue samples collected from six dogs were processed by a Rigenera device and by enzymatic digestion from two different body regions (lumbar and thigh region). Interestingly, the immunophenotypic analysis attested that cells from Rigenera^® were highly positive for the mesenchymal stem cells markers CD73 and CD90, less positive for hematopoietic CD45 and CD34, and negative for MHC class II antibodies (which play a role in immune responses). Finally, the Rigenera^® technology obtained micrografts with a 35% higher expression of the IL10 gene with relevant anti-inflammatory activities compared to the enzymatic digestion protocol. This evidence suggests a potential improved clinical outcome capable of modulating inflammation and immune responses.

Efficacy and safety of enflicoxib for treatment of canine osteoarthritis: A 6-week randomised, controlled, blind, multicentre clinical trial

BACKGROUND

Enflicoxib is a new COX-2 selective NSAID intended for the treatment of pain and inflammation associated with canine osteoarthritis.

METHODS

A prospective, multisite, blinded, randomised, controlled, parallel-group field study was performed to determine the efficacy and safety of enflicoxib in canine osteoarthritis. A total of 242 dogs were randomised to receive enflicoxib at 4 or 2 mg/kg, mavacoxib at 2 mg/kg or placebo, orally. Enflicoxib and placebo were administered once weekly from day 0 to day 35. Mavacoxib was administered on D0 and day 14. Veterinarians assessed efficacy with a numerical rating scale and owners used the Canine Brief Pain Inventory.

RESULTS

After 6 weeks, enflicoxib at 4 mg/kg showed the highest percentage of responders as assessed by the veterinarians (68%) and the owners (84%), followed by mavacoxib (62and 83%, respectively), and enflicoxib at 2 mg/kg (57 and 80%, respectively). All treatments reached statistical significance versus placebo, which obtained success rates of 37% and 53%, respectively. No differences in the incidence of adverse reactions were detected among the different groups.

CONCLUSIONS

Enflicoxib administered weekly for 6 weeks, at 4 mg/kg PO with an initial loading dose of 8 mg/kg, is efficacious and safe for the treatment of canine osteoarthritis.

Overweight in Swedish show dogs-prevalence and association with performance in competition

Background

The prevalence of overweight and obesity is increasing in companion dogs, but little is known of these conditions in show dogs. This study assessed body condition score (BCS) of show dogs of six selected popular breeds at a major Swedish dog show event and examined the association between BCS and performance in competition.

Results

At one of Sweden’s largest dog shows, BCS of 120 dogs of six different breeds was assessed by trained animal healthcare personnel, using a 9-point BCS scale with conditional cut-off for overweight set to BCS ≥ 6. Prevalence of overweight in the cohort was 32% but all overweight dogs except one displayed only slight overweight (BCS 6) and no dog was assessed as obese (BCS 8–9). Prevalence of overweight differed significantly between breeds (P < 0.0001) with Labrador retrievers, Golden retrievers and French bulldogs showing the highest mean BCS (5.6–5.7) and highest prevalence of overweight (50–67%). Lean and overweight dogs received awards and higher show awards (certificates) to the same extent, and no significant association between slight overweight and performance in competition was found.

Conclusions

Prevalence of overweight in Swedish show dogs was relatively high and in the same range as in the Swedish dog population as a whole. Dog owners, breeders and judges should be made aware of canine obesity problems and trained in BCS assessment, to better prevent canine overweight and associated health risks. This is particularly important for retriever and brachycephalic breeds, which showed high prevalence of slight overweight and have breed-specific health problems exacerbated by overweight. Owners and breeders of traditionally sturdy dog breeds should be informed that overweight dogs do not outperform lean dogs in competition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13028-021-00582-2.

Discovery of N-glycan Biomarkers for the Canine Osteoarthritis

Protein glycosylation is a post-translational modification that impacts on protein activity, stability, and interactions. It was sensitively altered by the cellular state and, therefore, is now used for a diagnostic or prognostic indicator of various human diseases such as cancer. To evaluate the clinical feasibility in the veterinary area, the N-glycan biomarkers were discovered from canine serum for the diagnosis of osteoarthritis (OA), which is one of the most common diseases of dogs. N-glycome was obtained from 20 μL of canine serum by the enzymatic cleavage followed by the purification and enrichment using solid-phase extraction. Independent compositions of 163 and 463 N-glycans were found from healthy control (n = 41) and osteoarthritis patients (n = 92), respectively. Initially, 31 of the potential biomarkers were screened by the p-values below 1.0 × 10⁻¹⁰ from ANOVA. Then, the area under the curve (AUC) and the intensity ratio between OA patient and healthy control (P/C ratio) were calculated. Considering the diagnostic efficacy, the AUC bigger than 0.9 and the P/C ratio larger than 3.0 were used to discover 16 N-glycans as diagnostic biomarkers. Particularly, five of the diagnostic biomarkers were AUC above 0.99 and three of N-glycans had AUC 1.0. The results suggest a clear possibility for N-glycan biomarkers to be used as a clinical tool in the veterinary medical area enabling to provide objective and non-invasive diagnostic information.

The dog 2.0: Lessons learned from the past

In recent years, concerns have been raised on the diversity, health and welfare of our (pedigree) dog population. Somewhat justified, the popular sire effect, population bottlenecks, the founder effect and inbreeding have left their marks on the dog as we know it. In order to improve the health and welfare of the canine population in general, individual breeding programs should adhere to the concept of ethical breeding (i.e. "the use of healthy animals true to their species in behaviour and looks, and when applicable, showing a sustainable performance") when population-specific breeding goals are defined. Even though every population has its own problems, the approach to get to possible solution(s) is similar. The starting point will always be the identification of which (un)desirable pheno- and genotypes are segregating and what their prevalence is, followed by an evaluation of the genetic diversity. Based on that information and, when applicable, additional criteria like breed standards, breeding goals can be defined. It is of critical importance that these goals are put forward with a long term vision in mind and with consensus from the stakeholders to ensure collaboration. Upon prioritization of the most important goals, when necessary with the help of specifically developed tools, the final step is choosing the most optimal combination of breeding strategies. This paper aims to provide a stepwise approach to identify and tackle population-specific problems encountered in breeding programs.

Prevalence of Canine Hip Dysplasia in Switzerland Between 1995 and 2016-A Retrospective Study in 5 Common Large Breeds

Canine hip dysplasia (CHD) is a genetic disease, modulated by epigenetic and environmental factors. To decrease the prevalence of CHD, the hip joints of many pure breed dogs are radiographed to identify dysplastic dogs not qualified for breeding. It has been shown that both, prevalence and severity of CHD may be reduced on the basis of phenotypic i.e., radiographic selection of breeding animals. The method has been used in many countries for over 50 years. In the present study, severity and prevalence of CHD in five common large breeds in Switzerland were evaluated since 1995. Both, prevalence and severity of CHD dropped in each breed between the periods 1995-1999 and 2010-2016. The prevalence decreased in Golden Retrievers from 25 to 9% and in Labrador Retrievers from 16 to 3%, respectively. In the Flat-Coated Retriever, prevalence in general was low, decreasing from 6 to 3%. In the Bernese mountain dog and the German shepherd dog, a decrease from 21 to 12% and from 46 to 18%, respectively, was observed. However, the rather low overall rate of radiographed dogs (Retrievers: 11 to 18%, Bernese Mountain dogs: 23% and German Shepherd dogs: 31%) does not allow to draw reliable conclusions regarding the true prevalence of CHD for the entire population of these breeds in Switzerland.

Effects of a nutritional supplement in dogs affected by osteoarthritis

Osteoarthritis is a form of chronic joint inflammation caused by the deterioration of the joint cartilage, accompanied by chronic pain, lameness and stiffness, particularly after prolonged activity. Alternative treatments of canine osteoarthritis would be desirable and, recently nutraceuticals, have been proposed for this purpose. Twenty cross breed adult dogs affected by osteoarthritis were enrolled and equally divided into two groups (control vs. experimental). The nutritional supplement (Dynamopet srl, Verone, Italy) was administered for 90 days to the dogs of the experimental group in order to evaluate its metabolic and locomotor effects. All the clinical signs (lameness, pain on manipulation and palpation, range of motion and joint swelling) significantly (p < 0.01) improved during the trial as regards the experimental group. This group showed a significantly lower joint score than the control group (mean value 7.40 vs. 3.80). With regard to haematology, the mean corpuscular volume resulted significantly (p < 0.01) higher in the experimental group, i.e. alkaline phosphatase, cholesterol and triglycerides values decreased and were significantly (p < 0.01) lower than the control one, thus suggesting an improvement in bone remodelling and lipid metabolism. A decrease in the reactive oxygen metabolites and an increase in the biological antioxidant potential demonstrated an improvement in oxidative stress during the trial in the experimental group compare to the control group. Interleukins 6 decreased in the experimental group, while interleukins 10 resulted in the opposite trend. Moreover, the administration of up to 3 months of the studied supplement was well tolerated in the dogs and caused no adverse effects.

Genetic improvement of hip-extended scores in 3 breeds of guide dogs using estimated breeding values: Notable progress but more improvement is needed

Two hip quality phenotypes-a hip-extended score assigned by a board certified radiologist and the PennHIP distraction index-were analyzed to estimate genetic parameters and to calculate estimated breeding values used for selecting replacement breeders. Radiographs obtained at 12-18 months of age were available on 5,201 German Shepherd Dogs, 4,987 Labrador Retrievers and 2,308 Golden Retrievers. Obtained by fitting a two-trait model using Bayesian techniques, estimates of heritability for the hip-extended score were 0.76, 0.72, and 0.41 in German Shepherd Dogs, Labrador Retrievers, and Golden Retrievers, respectively, while estimated heritabilities for distraction index were 0.60, 0.66 and 0.59, respectively. Genetic correlations between the two hip quality measures were -0.28 in German Shepherd Dogs, -0.21 in Labrador Retrievers, and -0.29 in Golden Retrievers. Genetic selection for improved hip quality based upon the hip extended score phenotype began in 1980. Among first generation puppies, 34% of 273 German Shepherd Dogs, 55% of 323 Labrador Retrievers, and 43% of 51 Golden Retrievers had an Excellent hip extended score. After 8 generations of selection, mostly based on estimated breeding values derived from the hip extended score, over 93% of 695 German Shepherd Dogs, 94% of 528 Labrador Retrievers, and 87% of 116 Golden Retrievers received an Excellent hip extended score. With respect to PennHIP distraction index values among these same dogs, median values were at or above 0.30 for all 3 breeds meaning that half or more of dogs possessing the Excellent hip-extended-score phenotype remained susceptible to developing the osteoarthritis of canine hip dysplasia. Genetic improvement of the hip-extended-view phenotype to its desired biological endpoint left a surprising proportion of dogs expressing sufficient joint laxity to place them in an osteoarthritis at-risk state as they age. Only by directly applying selection pressure to reduce distraction index was marked reduction in joint laxity noted.

A randomized, double-blind, prospective, placebo-controlled study of the efficacy of a diet supplemented with curcuminoids extract, hydrolyzed collagen and green tea extract in owner's dogs with osteoarthritis

BACKGROUND

We have previously demonstrated that a mixture of Curcuminoids extract, hydrolyzed COllagen and green Tea extract (CCOT) inhibited inflammatory and catabolic mediator's synthesis by bovine and human chondrocytes. A randomly allocated, double-blind, prospective, placebo-controlled study was performed to evaluate the efficacy of a diet containing this CCOT mixture on dogs with naturally occurring osteoarthritis (OA). Therefore, 42 owner's dogs with OA were randomly assigned to receive for 3 months an experimental diet (control) or the same diet supplemented with CCOT.

RESULTS

Ground reaction forces did not show statistical differences between groups. After 3 months of feeding, there was a significant reduction of pain at manipulation in the CCOT group, but not in the control group. The evolution for pain at manipulation depended on the diet. The three other parameters evaluated by veterinary subjective assessment (lameness, pain at palpation and joint mobility) did not show statistical differences. Concerning owner subjective assessment, pain severity score worsened in the control group but remained stable in CCOT group. The evolution for pain severity depended on the diet. No statistical difference was found for pain interference, except for the ability to rise to standing from lying down, which was significantly improved in the CCOT compared to the control group. Serum OA biomarkers did not show statistical differences.

CONCLUSIONS

Objective variables measured, such as ground reaction forces and OA biomarkers, did not show statistical differences. However, indicators of pain appeared reduced in dogs receiving CCOT mixture for 3 months. The difference of evolution between groups suggests that a greater number of dogs may be necessary to reach a stronger effect on other parameters.

Physical Rehabilitation for the Management of Canine Hip Dysplasia

Hip dysplasia is among the most common orthopedic conditions affecting dogs. Joint laxity is responsible for abnormal development of the femoral head and acetabulum, leading to excessive wear of the articular cartilage. Wear leads to secondary osteoarthritis. Rehabilitation is either conservative or after surgical management. Conservative rehabilitation therapies are directed at decreasing pain, improving hip range of motion (ROM), and building or maintaining muscle mass. Postoperatively, rehabilitation focuses on decreasing postoperative pain and inflammation, improving comfort and limb use, and protecting the surgical site. Once the patient has healed, rehabilitation is directed at improving ROM and promoting muscle mass.

Canine Hip Dysplasia: Diagnostic Imaging

Diagnostic imaging is the principal method used to screen for and diagnose hip dysplasia in the canine patient. Multiple techniques are available, each having advantages, disadvantages, and limitations. Hip-extended radiography is the most used method and is best used as a screening tool and for assessment for osteoarthritis. Distraction radiographic methods such as the PennHip method allow for improved detection of laxity and improved ability to predict future osteoarthritis development. More advanced techniques such as MRI, although expensive and not widely available, may improve patient screening and allow for improved assessment of cartilage health.

Etiopathogenesis of Canine Hip Dysplasia, Prevalence, and Genetics

First identified in 1935, canine hip dysplasia is thought to be the most common orthopedic condition diagnosed in the dog. It is most prevalent in large and giant breed dogs, with a complex polygenic mode of inheritance, and relatively low heritability. External factors including caloric intake when growing have a significant effect on phenotypic expression. Initial joint laxity progresses to osteoarthritis due to subluxation and abnormal wearing. Selective breeding programs to attempt to decrease prevalence have shown modest results so far.

Long-term genetic selection reduced prevalence of hip and elbow dysplasia in 60 dog breeds

Canine hip dysplasia (CHD) and elbow dysplasia (ED) impact the health and welfare of all dogs. The first formally organized assessment scheme to improve canine health centered on reducing the prevalence of these orthopedic disorders. Phenotypic screening of joint conformation remains the currently available strategy for breeders to make selection decisions. The present study evaluated the efficacy of employing phenotypic selection on breed improvement of hips and elbows using the Orthopedic Foundation for Animals complete database spanning the 1970–2015 time period. Sixty breeds having more than 1000 unique hip evaluations and 500 elbow evaluations (1,056,852 and 275,129 hip and elbow records, respectively) were interrogated to derive phenotypic improvement, sex and age at time of assessment effects, correlation between the two joints, heritability estimates, estimated breeding values (EBV), and effectiveness of maternal/paternal selection. The data demonstrated that there has been overall improvement in hip and elbow conformation with a reduction in EBV for disease liability, although the breeds differed in the magnitude of the response to selection. Heritabilities also differed substantially across the breeds as did the correlation of the joints; in the absence of a universal association of these differences with breed size, popularity, or participation in screening, it appears that the breeds themselves vary in genetic control. There was subtle, though again breed specific, impact of sex and older ages on CHD and ED. There was greater paternal impact on a reduction of CHD. In the absence of direct genetic tests for either of these two diseases, phenotypic selection has proven to be effective. Furthermore, the data underscore that selection schemes must be breed specific and that it is likely the genetic profiles will be unique across the breeds for these two conditions. Despite the advances achieved with phenotypic selection, incorporation of EBVs into selection schemes should accelerate advances in hip and elbow improvement.

Radiographic evaluation of early periprosthetic acetabular bone contrast and prosthetic head acetabular coverage after uncemented and cemented total hip prosthesis in dogs

BACKGROUND

Coxofemoral osteoarthritis is a chronic, disabling condition affecting people and dogs, with THA providing an excellent return to function in severely affected joints. The principal role of THA is to restore an adequate range of motion to the hip joint while transferring load from the acetabulum in order to improve the survival of the implant and enhance the limb function in the short and long terms. The objectives of the study reported here were, therefore, to radiographically evaluate periprosthetic acetabular bone GV and to assess prosthetic head acetabular coverage after 4 months of uncemented and cemented THA in dogs. Means periprosthetic acetabular GV for each and combined 3 regions of interest (zones 1, 2 and 3) were calculated immediately and 4 months after THA. Prosthetic head Norberg (PHN) angle was also measured to assess the degree of prosthetic head acetabular coverage after 4 months of surgery.

RESULTS

Zones 2 and 3 showed a significant increase in the mean bone GV after 4 months of uncemented THA. No differences in zones 1-3 after 4 months of cemented THA. Combined zones showed a significant increase in overall mean bone GV 4 months after uncemented THA; whereas, no changes were identified after 4 months of cemented THA. The PHN angles did not change after 4 months of uncemented and cemented THA and did not differ significantly between the 2 designs of hip arthroplasty.

CONCLUSIONS

Regional periprosthetic acetabular bone GV varies with the design of THA. None of the designs showed periprosthetic acetabular bone lucency. No differences identified in the degree of prosthetic head acetabular coverage in both designs, indicating proper implant stability after 4 months of surgery. Further longer-term investigation on larger population is however still warranted.

Emerging insights into the genetic basis of canine hip dysplasia

Canine hip dysplasia (CHD) is the most common inherited polygenic orthopedic trait in dogs with the phenotype influenced also by environmental factors. This trait was described in the dog in 1935 and leads to a debilitating secondary hip osteoarthritis. The diagnosis is confirmed radiographically by evaluating signs of degenerative joint disease, incongruence, and/or passive hip joint laxity. There is no ideal medical or surgical treatment so prevention based on controlled breeding is the optimal approach. The definitive CHD diagnosis based on radiographic examination involves the exposure to ionizing radiation under general anesthesia or heavy sedation but the image does not reveal the underlying genetic quality of the dog. Phenotypic expression of CHD is modified by environmental factors and dogs with a normal phenotype can be carriers of some mutations and transmit these genes to their offspring. Programs based on selection of dogs with better individual phenotypes for breeding are effective when strictly applied but remain inferior to the selection of dogs based on estimation of breeding values. Molecular studies for dissecting the genetic basis of CHD are ongoing, but progress has been slow. In the future, the recommended method to improve hip quality in controlled breeding schemes, which will allow higher selection pressure, would be based on the estimation of the genomic breeding value. Since 2012, a commercial DNA test has been available for Labrador Retrievers using a blood sample and provides a probability for development of CHD but we await evidence that this test reduces the incidence or severity of CHD.

Associations between early radiographic and computed tomographic measures and canine hip joint osteoarthritis at maturity

OBJECTIVE

To evaluate associations of measures assessed by radiography, 2-D CT, and 3-D CT of the hip joints of immature dogs with osteoarthritis in the same joints at maturity.

ANIMALS

46 hound-type dogs from a colony predisposed to osteoarthritis.

PROCEDURES

Images of hip joints (1/dog) were obtained at 16, 32, and 104 weeks of age. Radiographic measures included Norberg angle, distraction index, and osteoarthritis score. Two-dimensional CT measures included acetabular index, percentage of femoral head coverage, and center edge, horizontal toit externe, acetabular anteversion, and ventral, dorsal, and horizontal acetabular sector angles. Three-dimensional CT measures were femoral head and neck volume, femoral neck angle, and femoral head and neck radius. Differences among measures at 16 and 32 weeks in dogs with different osteoarthritis scores at later time points, relationships among variables at each time point, and relationships of single and combined measures with the presence of osteoarthritis at 104 weeks were evaluated.

RESULTS

The 16- and 32-week distraction index, center edge angle, dorsal acetabular sector angle, horizontal acetabular sector angle, percentage of femoral head coverage, acetabular index, and Norberg angle and the 32-week femoral neck angle varied significantly with osteoarthritis severity at 104 weeks. Presence of osteoarthritis in mature dogs was most strongly associated with 16-week combined measures of distraction index and center edge angle and 32-week combined measures of dorsal acetabular sector angle and Norberg angle.

CONCLUSIONS AND CLINICAL RELEVANCE

Changes in hip joint morphology associated with radiographic signs of osteoarthritis were detectable as early as 16 weeks of age and varied with osteoarthritis severity in adult dogs. The use of combined hip joint measures may improve early identification of dogs predisposed to hip joint osteoarthritis.

Estimated breeding values for canine hip dysplasia radiographic traits in a cohort of Australian German Shepherd dogs

Canine hip dysplasia (CHD) is a serious and common musculoskeletal disease of pedigree dogs and therefore represents both an important welfare concern and an imperative breeding priority. The typical heritability estimates for radiographic CHD traits suggest that the accuracy of breeding dog selection could be substantially improved by the use of estimated breeding values (EBVs) in place of selection based on phenotypes of individuals. The British Veterinary Association/Kennel Club scoring method is a complex measure composed of nine bilateral ordinal traits, intended to evaluate both early and late dysplastic changes. However, the ordinal nature of the traits may represent a technical challenge for calculation of EBVs using linear methods. The purpose of the current study was to calculate EBVs of British Veterinary Association/Kennel Club traits in the Australian population of German Shepherd Dogs, using linear (both as individual traits and a summed phenotype), binary and ordinal methods to determine the optimal method for EBV calculation. Ordinal EBVs correlated well with linear EBVs (r = 0.90–0.99) and somewhat well with EBVs for the sum of the individual traits (r = 0.58–0.92). Correlation of ordinal and binary EBVs varied widely (r = 0.24–0.99) depending on the trait and cut-point considered. The ordinal EBVs have increased accuracy (0.48–0.69) of selection compared with accuracies from individual phenotype-based selection (0.40–0.52). Despite the high correlations between linear and ordinal EBVs, the underlying relationship between EBVs calculated by the two methods was not always linear, leading us to suggest that ordinal models should be used wherever possible. As the population of German Shepherd Dogs which was studied was purportedly under selection for the traits studied, we examined the EBVs for evidence of a genetic trend in these traits and found substantial genetic improvement over time. This study suggests the use of ordinal EBVs could increase the rate of genetic improvement in this population.

Chronology of hip dysplasia development in a cohort of 48 Labrador retrievers followed for life

OBJECTIVE

To determine the chronology of radiographic signs of canine hip dysplasia (CHD), specifically joint laxity and secondary osteoarthritis (OA).

STUDY DESIGN

Longitudinal cohort study.

ANIMALS

Paired littermates, 48 Labrador retrievers.

METHODS

Conventional, ventrodorsal, hip-extended (HE) radiographs were evaluated yearly for CHD according to the subjective criteria of the Orthopedic Foundation for Animals (OFA). PennHIP screening was performed at 2 years of age to assess joint laxity by distraction index (DI). Histopathologic evaluation of coxofemoral joints was performed at the dogs' natural end of life.

RESULTS

Coxofemoral subluxation, as identified on the HE radiograph occurred by 2 years of age and not thereafter. Accuracy of OFA-criteria scoring was poor: 55% of dogs scored "normal" at 2 years of age became radiographically dysplastic by the end of life (45% negative predictive value, NPV); 92% of the dogs scored as normal at 2 years of age had histopathologic OA of CHD (8% NPV). The DI predicted all 48 dogs to be susceptible to OA of CHD and 98% had radiographic or histopathologic OA by the end of life.

CONCLUSION

OFA-criteria score was profoundly influenced by environmental factors, such as diet restriction and age, reducing its value as a selection criterion. DI measurements were not influenced by dietary treatment suggesting higher trait heritability.

Effect of analgesic therapy on clinical outcome measures in a randomized controlled trial using client-owned dogs with hip osteoarthritis

Background

Pain and impaired mobility because of osteoarthritis (OA) is common in dogs and humans. Efficacy studies of analgesic drug treatment of dogs with naturally occurring OA may be challenging, as a caregiver placebo effect is typically evident. However, little is known about effect sizes of common outcome-measures in canine clinical trials evaluating treatment of OA pain. Forty-nine client-owned dogs with hip OA were enrolled in a randomized, double-blinded placebo-controlled prospective trial. After a 1 week baseline period, dogs were randomly assigned to a treatment (ABT-116 – transient receptor potential vanilloid 1 (TRPV1) antagonist, Carprofen – non-steroidal anti-inflammatory drug (NSAID), Tramadol - synthetic opiate, or Placebo) for 2 weeks. Outcome-measures included physical examination parameters, owner questionnaire, activity monitoring, gait analysis, and use of rescue medication.

Results

Acute hyperthermia developed after ABT-116 treatment (P < 0.001). Treatment with carprofen (P ≤ 0.01) and tramadol (P ≤ 0.001) led to improved mobility assessed by owner questionnaire. Nighttime activity was increased after ABT-116 treatment (P = 0.01). Kinetic gait analysis did not reveal significant treatment effects. Use of rescue treatment decreased with treatment in the ABT-116 and Carprofen groups (P < 0.001). Questionnaire score and activity count at the end of treatment were correlated with age, clinical severity at trial entry, and outcome measure baseline status (S_R ≥ ±0.40, P ≤ 0.005). Placebo treatment effects were evident with all variables studied.

Conclusion

Treatment of hip OA in client-owned dogs is associated with a placebo effect for all variables that are commonly used for efficacy studies of analgesic drugs. This likely reflects caregiver bias or the phenomenon of regression to the mean. In the present study, outcome measures with significant effects also varied between groups, highlighting the value of using multiple outcome measures, as well as an a priori analysis of effect size associated with each measure. Effect size data from the present study could be used to inform design of future trials studying analgesic treatment of canine OA. Our results suggest that analgesic treatment with ABT-116 is not as effective as carprofen or tramadol for treatment of hip arthritis pain in client-owned dogs.

Housing- and exercise-related risk factors associated with the development of hip dysplasia as determined by radiographic evaluation in a prospective cohort of Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds in Norway

OBJECTIVE

To identify housing- and exercise-related risk factors associated with the development of hip dysplasia (HD) as determined by radiographic evaluation in Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds in Norway.

ANIMALS

501 client-owned dogs from 103 litters.

PROCEDURES

Dogs were assessed from birth until official radiographic screening for HD at 12 (Labrador Retriever [n = 133] and Irish Wolfhound [63]) or 18 (Newfoundland [125] and Leonberger [180]) months of age. Information regarding housing and exercise conditions during the preweaning and postweaning periods was obtained with questionnaires. Multivariable random effects logistic regression models were used to identify housing- and exercise-related risk factors associated with the development of radiographically detectable HD.

RESULTS

Puppies walking on stairs from birth to 3 months of age had an increased risk of developing HD. Factors associated with a decreased risk of developing HD included off-leash exercise from birth to 3 months of age, birth during the spring and summer, and birth on a farm. Significant clustering of dogs with HD was detected within litters.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that puppies ≤ 3 months old should not be allowed access to stairs, but should be allowed outdoor exercise on soft ground in moderately rough terrain to decrease the risk for developing radiographically detectable HD. These findings could be used as practical recommendations for the prevention of HD in Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds.

Translational animal models using veterinary patients - An example of canine osteoarthritis (OA)

Background and purpose The use of laboratory animals in pain research has powerfully contributed to our detailed understanding of the physiological mechanisms of pain. Animal models also represent an essential tool to screen and select novel drug molecules with potentially analgesic properties. Despite of the inevitable input of laboratory animal trials, recent studies have shown that animal pain models have repeatedly failed to predict clinical analgesic efficacy and adverse side effects of potential drug molecules in human pain patients. This paper provides a review of the laboratory animal models of OA, which have been developed to test efficacy of novel analgesics. The paper also presents spontaneous OA in canine veterinary patients, and methods to observe chronic pain in nonverbal dogs. Methods PubMed data base was searched as a reference list to locate most relevant articles. A number of 118 articles including 4 reviews were located. Web pages of 4 establishments and 2 private organizations were also accessed. Results The clinical expression and pathogenesis of naturally occurring OA in dogs is considered an analogous disease that occurs in humans, including pain and lameness. OA may occur in any joint in dogs as well as in humans. Primary idiopathic OA in dogs is rare, but certain breeds may be predisposed to it. For the most part, canine OA is considered secondary to acquired or congenital musculoskeletal disorders. Concomitant factors, such as aging and obesity, likely accelerate progression. However, mechanical factors appear to predominate in the etiopathogenesis of canine spontaneous OA. Both subjective (validated questionnaire) and objective (gait analysis) tools are available to measure OA related pain in dogs. Information on the prevalence of canine OA is limited, but rough surveys suggest that 11 million dogs in the United States and 5 million in Europe could suffer from OA. Ethical considerations concerning the use of privately owned dogs can be resolved by a careful experimental design. Conclusion Canine spontaneous OA could serve as a translational animal model that would more closely mimick clinical OA related pain conditions in humans. Privately owned dogs would make a solution to fix the gap between animal pain models and clinical trials when testing potential analgesic drug molecules. Close interdisciplinary cooperation would guarantee that both scientific and ethical intentions would be achieved. Implications The predictability of translational pain research would improve by using privately owned dogs as chronic pain models when testing novel analgesics.

The S-measurement in the diagnosis of canine hip dysplasia

OBJECTIVE

To propose a direct measure of subluxation of the femoral head (S) in the assessment of hip joint laxity and evaluate it for clinical use.

STUDY DESIGN

Method comparison study.

ANIMALS

Dogs (n = 51).

METHODS

Dogs were sedated or anesthetized for a dorsolateral subluxation (DLS) examination. Two sets of radiographs were acquired, 1 each by a different technologist. A calibrated measuring bar was included on the image at the height of the hip to assess magnification. The DLS was calculated for each hip and different persons unaware of these details measured the "S"-value. One person measured the S-value 3 times over 3 days. Box plots were used to determine a cut-off for the empiric (8 mm) and corrected (4 mm) S-value.

RESULTS

Of 51 dogs, 33 were dysplastic based on a DLS score <55%. Magnification and body weight were strongly correlated (r = 0.4922, P = .0006). Both empiric and corrected S measurements showed good agreement with the DLS score (κ = 0.688 and κ = 0.681, respectively). The corrected S measurement produced more false negatives. Bland-Altman analysis showed interobserver and technician variance acceptable for clinical use (limits of agreement < ±3 mm). Intraobserver repeatability was acceptable for the right hip (95% of differences were ≤1.3 mm and 100% ≤ 1.9) but not for the left hip.

CONCLUSION

Using a cut-off value of 5 mm, the empirical S measurement can be used to exclude hip dysplasia in young dogs of various body proportions.

Selection against canine hip dysplasia: success or failure?

Canine hip dysplasia (CHD) is a multifactorial skeletal disorder which is very common in pedigree dogs and represents a huge concern for canine welfare. Control schemes based on selective breeding have been in operation for decades. The aim of these schemes is to reduce the impact of CHD on canine welfare by selecting for reduced radiographic evidence of CHD pathology as assessed by a variety of phenotypes. There is less information regarding the genotypic correlation between these phenotypes and the impact of CHD on canine welfare. Although the phenotypes chosen as the basis for these control schemes have displayed heritable phenotypic variation in many studies, success in achieving improvement in the phenotypes has been mixed. There is significant room for improvement in the current schemes through the use of estimated breeding values (EBVs), which can combine a dog's CHD phenotype with CHD phenotypes of relatives, other phenotypes as they are proven to be genetically correlated with CHD (especially elbow dysplasia phenotypes), and information from genetic tests for population-relevant DNA markers, as such tests become available. Additionally, breed clubs should be encouraged and assisted to formulate rational, evidenced-based breeding recommendations for CHD which suit their individual circumstances and dynamically to adjust the breeding recommendations based on continuous tracking of CHD genetic trends. These improvements can assist in safely and effectively reducing the impact of CHD on pedigree dog welfare.

A prospective study on canine hip dysplasia and growth in a cohort of four large breeds in Norway (1998-2001)

The study-objective was to measure the effect of weight and growth related parameters on the risk of development of Canine Hip Dysplasia (CHD). The hypothesis was that heavy and fast growing dogs of large sized breeds were at increased risk of development of CHD compared to lighter and slower growing dogs. A prospective cohort study was conducted among dogs of four large breeds: Newfoundland (NF), Leonberger (LEO), Labrador retriever (LR), and Irish wolfhound (IW). The dogs were privately owned with individualized nutrition and environment, and they were followed from birth and throughout the growth period until the official screening for CHD was performed. The study sample consisted of 501 dogs from 103 litters, with the breed distribution 125 NF, 180 LEO, 133 LR, and 63 IW. Because the dogs were clustered in litters a multivariable random effects logistic regression model was used to assess statistically significant growth-related risk factors for CHD. The estimated incidence risk of CHD was 36% in NF, 25% in LEO, 20% in LR, and 10% in IW. Based upon the final multilevel model it appears that the odds of CHD among both LR and IW (odds ratio (OR) 0.22) are about one-fifth of the odds for NF. The odds for LEO (OR 0.60) are not significantly different from NF. There appeared to be an inverse relationship between body weight at 3 months of age and odds of CHD, with an OR of 0.89 (P=0.044). The degree of clustering at the litter-level was high (22.6%) and highly significant (P<0.001). Findings failed to support the hypothesis that heavy and fast growing dogs from four large sized breeds were at increased risk for development of CHD. There might be other unmeasured environmental risk factors for CHD in this cohort of dogs, although the contribution of the genetic variance to the litter-level clustering also needs further investigation.

Evaluation of the relationship between Orthopedic Foundation for Animals' hip joint scores and PennHIP distraction index values in dogs

OBJECTIVE

To compare 2 screening methods for detecting evidence of hip dysplasia (Orthopedic Foundation for Animals [OFA] and PennHIP) in dogs.

DESIGN

Diagnostic test evaluation study. Animals-439 dogs >or= 24 months of age that received routine hip joint screening from June 1987 through July 2008.

PROCEDURES

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 >or= 0.30 (range, 0.14 to 0.61). Eighty-two percent of (183/223) dogs with OFA-rated good hip joints had a DI >or= 0.30 (range, 0.10 to 0.77), and 94% (79/84) of dogs with OFA-rated fair hip joints had a DI >or= 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 >or= 0.30. All dogs with OFA-rated borderline hip joints or mild, moderate, or severe hip dysplasia had a DI >or= 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.

Distraction index as a risk factor for osteoarthritis associated with hip dysplasia in four large dog breeds

OBJECTIVE

To determine if age, breed, gender, weight or distraction index (DI) influenced the risk of radiographic osteoarthritis (OA) of canine hip dysplasia (CHD) in four common dog breeds; the American bulldog, Bernese mountain dog, Newfoundland and standard poodle.

MATERIALS AND METHODS

This was a cross sectional prevalence study with 4349 dogs. Canine hips were evaluated using 3 radiographic projections: the hip-extended view, the compression view and the distraction view. The hip-extended view was examined for the presence of OA. The PennHIP distraction view was utilized to calculate the DI. For all breeds, a multiple logistic regression model incorporating age, weight, gender, and DI was created. For each breed, disease-susceptibility curves grouping dogs on the basis of age were constructed. Receiver-operating characteristic (ROC) curves were developed for each breed regardless of age.

RESULTS

For all breeds, DI was the most significant risk factor for the development of OA associated with CHD. Weight and age were also significant risk factors in all four breeds, but gender was not.

CLINICAL SIGNIFICANCE

Results from this study support previous findings, that irrespective of breed, the probability of radiographic OA increases with hip joint laxity as measured by the DI. Breed-specific differences in this relationship, however, warrant investigation of all breeds affected by CHD to determine inherent dependency of hip OA on joint laxity. Such findings guide veterinarians in helping dog breeders to make evidence-based breeding decisions and in informing dog owners to implement preventative treatments for CHD for dogs found to be at risk.

The relationship between the size of caudolateral curvilinear osteophyte of the canine femoral neck and the radiographic view

Caudolateral curvilinear osteophyte (CCO), an osteophyte at the site of joint capsule attachment on the caudal aspect of the femoral neck, has been advocated as a radiographic criterion for coxofemoral subluxation. The correlation between the presence of CCO on radiographs (radiographic-CCO), the size of the CCO (CCO index) on three-dimensional computed tomographic (CT) images, and hip evaluation using transverse CT images was assessed in 22 Border Collies. CCOs were detected on the radiographs and CT images of 32% and 100% femurs, respectively. The CCO index correlated significantly with radiographic-CCO, but a large CCO index did not necessarily imply that the CCO was visible on radiographs. Hence, radiographic-CCO findings should be used cautiously in hip evaluation of Border Collies.

Introduction: Darwinian selection, selective breeding and the welfare of animals

The 150th anniversary of the publication of The Origin of Species… is a good time to consider how selection can affect welfare — the quality of life. Darwin (1859) quoted Youatt's description of selective breeding: “…the magician's wand, by means of which he may summon into life whatever form and mould he pleases”. Evolution has fairly recently included us humans in its toolbox, alongside its older instruments, such as climate and disease, as significant agents of selection. We have taken to this work vigorously and have summoned into life an extraordinary array of creatures. It is only much more recently, with the development of interest in animal welfare science, that the welfare consequences of this have begun to be critically reviewed. There are two ways that selection can affect welfare: (i) by resulting in changes that make aversive feelings more likely, eg by predisposing to disease or by altering behaviour such as to increase risk of disease or injury, and (ii) by altering sensitivity of the affect systems such that animals feel, for example, more (or less) pain or fear in response to a stimulus than their ancestors would have. Comparing natural and human selection — that is, the simultaneous scrutiny of all aspects of biology as opposed to our selection for one or two features that appeal to us — Darwin (1859) wrote: “Can we wonder, then, that nature's productions should be far ‘truer’ in character than man's productions; that they should be infinitely better adapted to the most complex conditions of life, and should plainly bear the stamp of far higher workmanship”. The aims of this meeting were to discuss how selection can affect welfare and how we can improve our workmanship in the interests of animal welfare.