Complications and outcomes of total hip arthroplasty in dogs with luxoid hip dysplasia: 18 cases (2010-2022).

OBJECTIVE: To describe the complications and outcomes in dogs with luxoid hip dysplasia (LH) undergoing total hip arthroplasty (THA) and compare complication rates with THA in non-LH dogs. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Client-owned dogs (n = 217) undergoing primary THA (n = 238). METHODS: Medical records (2010-2022) of dogs undergoing THA were reviewed, and LH was defined as complete dorsal displacement of the femoral head from the acetabulum on lateral projection radiographs. Major or catastrophic complications, revisions, and outcomes were recorded for all dogs and they were compared between LH and non-LH groups. RESULTS: Eighteen cases met the subcriterion for the LH group and 220 cases met the subcriterion for inclusion in the non-LH group. There were 14 complications in 13/18 dogs with LH; seven were intraoperative (femoral fissure/fracture) and seven were postoperative (dorsal luxation, n = 5; femoral fracture, n = 1; acetabular cup septic loosening, n = 1). Revisions were performed for all LH dogs that encountered complications; satisfactory outcomes were achieved in 12/13 dogs. Overall, LH dogs had a higher risk of developing complications (p < .001), including intraoperative fracture (p < .001) and postoperative dorsal luxation (p = .019) when compared with non-LH dogs. CONCLUSION: Luxoid hip dysplasia was associated with a higher risk of major complications following THA in dogs, specifically intraoperative fissure/fracture and postoperative dorsal luxation. Despite the increased risk, revisions typically yielded satisfactory outcomes. CLINICAL SIGNIFICANCE: Luxoid hip dysplasia is an important risk factor for the development of major complications in dogs undergoing THA.

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.

B-mode ultrasonography and ARFI elastography of articular and peri-articular structures of the hip joint in non-dysplastic and dysplastic dogs as confirmed by radiographic examination.

BACKGROUND: Canine hip dysplasia is a common orthopedic disease in veterinary practice. The diagnosis is made by radiographic examinations that evaluate bone alterations associated with hip dysplasia. Although radiographic examination is the gold standard for diagnosis, it does not allow a detailed evaluation of soft tissues such as the joint capsule and periarticular muscles. This study aimed to evaluate the accuracy of B-mode ultrasonography and acoustic radiation force impulse (ARFI) elastography in assessing the joint capsule and periarticular muscles of dogs using the Orthopedic Foundation of Animals (OFA) classification and the distraction index (DI) in the early and late diagnosis of hip dysplasia. This study sought to propose a protocol for the ultrasonographic evaluation of the structures involved in canine hip dysplasia. METHODS: Radiographic and ultrasonographic evaluations were performed on 108 hip joints of 54 dogs. Thirty dogs were older than 2 years and 24 were aged between 4 and 10 months. RESULTS: It was verified that an increase in pectineus muscle stiffness (cutoff value > 2.77 m/s) by elastography in some dysplastic dogs and an increase in the thickness of the joint capsule (cutoff value > 0.9 mm) in B-mode ultrasonography, were associated with a distraction index > 0.5, with both having a positive correlation. In B-mode ultrasonographic evaluation, the presence of signs of degenerative joint disease, such as irregularities of the cranial edge of the acetabulum and femoral head, were associated with a distraction index > 0.5 in canines, with a specificity of 94%. In adult dogs, the findings of degenerative joint disease on ultrasound were associated with a diseased OFA classification (P < 0.05). Measurement of the joint capsule > 1.10 mm was diagnostic for dysplasia in unhealthy dogs by OFA. CONCLUSIONS: ARFI elastography has shown that the pectineus muscle may experience changes in stiffness in dysplastic animals. Additionally, changes in joint capsule thickness can be identified in B-mode in young and adult dogs with dysplastic joints, which contributes to the diagnosis of hip dysplasia.

Mechanical osteoarthritis of the hip in a one medicine concept: a narrative review.

Human and veterinary medicine have historically presented many medical areas of potential synergy and convergence. Mechanical osteoarthritis (MOA) is characterized by a gradual complex imbalance between cartilage production, loss, and derangement. Any joint instability that results in an abnormal overload of the joint surface can trigger MOA. As MOA has a prevailing mechanical aetiology, treatment effectiveness can only be accomplished if altered joint mechanics and mechanosensitive pathways are normalized and restored. Otherwise, the inflammatory cascade of osteoarthritis will be initiated, and the changes may become irreversible. The management of the disease using non-steroidal anti-inflammatory drugs, analgesics, physical therapy, diet changes, or nutraceuticals is conservative and less effective. MOA is a determinant factor for the development of hip dysplasia in both humans and dogs. Hip dysplasia is a hereditary disease with a high incidence and, therefore, of great clinical importance due to the associated discomfort and significant functional limitations. Furthermore, on account of analogous human and canine hip dysplasia disease and under the One Medicine concept, unifying veterinary and human research could improve the well-being and health of both species, increasing the acknowledgement of shared diseases. Great success has been accomplished in humans regarding preventive conservative management of hip dysplasia and following One Medicine concept, similar measures would benefit dogs. Moreover, animal models have long been used to better understand the different diseases' mechanisms. Current research in animal models was addressed and the role of rabbit models in pathophysiologic studies and of the dog as a spontaneous animal model were highlighted, denoting the inexistence of rabbit functional models to investigate therapeutic approaches in hip MOA.

Evaluation of the thermographic response of the lumbar region in dogs with bilateral hip osteoarthritis.

Infrared thermography is suggested as a method of medical assistance for evaluating anatomical regions where there may be some inflammatory or painful condition that requires immediate medical attention. For this reason, this study aimed to characterize digital thermography of the lumbar region in police working dogs with hip osteoarthritis, 47 dogs with bilateral hip osteoarthritis were evaluated. A thermographic dorsoventral view of the dogs' backs were obtained, and mean and maximum temperatures were determined. In addition, results from the Canine Brief Pain Inventory, Liverpool Osteoarthritis in Dogs (LOAD), the Canine Orthopedic Index, and weight-bearing distribution evaluation were collected. Results were compared with an Independent Samples T-Test or ANOVA, followed by an LSD post hoc. Multiple regression was run to predict temperatures from age, sex, breed, body weight, and Orthopedic Foundation for Animals hip score and to predict clinical metrology scores and weight-bearing distribution results from temperature results. The sample included 28 males and 19 females, with a mean age of 6.3 ± 2.5 years and bodyweight of 26.9 ± 5.1 kg, with osteoarthritis hip scores of mild (70.2%), moderate (21.3%), and severe (8.5%). Significant differences were observed in mean temperatures between German Shepherd Dogs (GSD) and Labrador Retrievers (LR) (p < 0.01), and LR and Belgian Malinois (BM) (p=0.02). Mean temperature contributed to the prediction of LOAD and stiffness. LR showed significantly higher temperature values than GSD and BM. No differences were observed between osteoarthritis hip scores and mean temperature values contributed to LOAD scores' prediction. This relation needs to be addressed in further studies, involving a larger number of animals, and to determine changes in response to treatment.

Novel protective and risk loci in hip dysplasia in German Shepherds.

Canine hip dysplasia is a common, non-congenital, complex and hereditary disorder. It can inflict severe pain via secondary osteoarthritis and lead to euthanasia. An analogous disorder exists in humans. The genetic background of hip dysplasia in both species has remained ambiguous despite rigorous studies. We aimed to investigate the genetic causes of this disorder in one of the high-risk breeds, the German Shepherd. We performed genetic analyses with carefully phenotyped case-control cohorts comprising 525 German Shepherds. In our genome-wide association studies we identified four suggestive loci on chromosomes 1 and 9. Targeted resequencing of the two loci on chromosome 9 from 24 affected and 24 control German Shepherds revealed deletions of variable sizes in a putative enhancer element of the NOG gene. NOG encodes for noggin, a well-described bone morphogenetic protein inhibitor affecting multiple developmental processes, including joint development. The deletion was associated with the healthy controls and mildly dysplastic dogs suggesting a protective role against canine hip dysplasia. Two enhancer variants displayed a decreased activity in a dual luciferase reporter assay. Our study identifies novel loci and candidate genes for canine hip dysplasia, with potential regulatory variants in the NOG gene. Further research is warranted to elucidate how the identified variants affect the expression of noggin in canine hips, and what the potential effects of the other identified loci are.

Clinical outcomes of double pelvic osteotomies in eight dogs with hip dysplasia aged 10-28 months.

OBJECTIVE: To report the short-term outcome of double pelvic osteotomy (DPO) in dogs with canine hip dysplasia ≥10 months of age. STUDY DESIGN: Case series. ANIMALS OR SAMPLE POPULATION: Eleven hips in eight dogs aged between 10 to 28 months. METHODS: Dogs clinically affected by hip dysplasia with a hip reduction angle <40°, subluxation angle <25°, dorsal acetabular rim angle between 7.5-25°, and minimal osteoarthritic changes were considered as candidates for DPO. The clinical outcome was subjectively assessed using a lameness score and pain scale upon hip extension. Norberg angle, percentage of the area of the femoral head coverage, percentage of linear femoral head coverage, pelvic width dimensions were measured on pre and postoperative radiographs. RESULTS: At the 8-week follow-up examination, all the dogs had no lameness with no pain upon hip extension. Median Norberg angle increased by 21.8% (p < .01), median percentage of the area of the femoral head coverage increased by 66.7% (p < .01) and percentage of linear femoral head coverage increased by 162.5% (p < .01) 1 year after DPO. No changes to pelvic canal width after DPO were detected. CONCLUSION: Double pelvic osteotomy improved joint congruity and clinical signs in dogs affected by hip dysplasia without osteoarthritis that were ≥10 months of age. CLINICAL SIGNIFICANCE (OR IMPACT): Double pelvic osteotomy may be a treatment option for dogs with hip dysplasia ≥10 months of age. A large study assessing long-term outcomes is indicated.

An across-breed validation study of 46 genetic markers in canine hip dysplasia.

BACKGROUND: Canine hip dysplasia (CHD) is a common disease, with a complex genetic background. Dogs with severe CHD sometimes also suffer from osteoarthritis (OA), an inflammatory, often painful and incurable condition. Previous studies have reported breed-specific genetic loci associated with different hip dysplasia and OA phenotypes. However, the independent replication of the known associations within or across breeds has been difficult due to variable phenotype measures, inadequate sample sizes and the existence of population specific variants. RESULTS: We execute a validation study of 46 genetic markers in a cohort of nearly 1600 dogs from ten different breeds. We categorize the dogs into cases and controls according to the hip scoring system defined by the Fédération Cynologique Internationale (FCI). We validate 21 different loci associated on fourteen chromosomes. Twenty of these associated with CHD in specific breeds, whereas one locus is unique to the across-breed study. We show that genes involved in the neddylation pathway are enriched among the genes in the validated loci. Neddylation contributes to many cellular functions including inflammation. CONCLUSIONS: Our study successfully replicates many loci and highlights the complex genetic architecture of CHD. Further characterisation of the associated loci could reveal CHD-relevant genes and pathways for improved understanding of the disease pathogenesis.

Genome-wide association studies for canine hip dysplasia in single and multiple populations - implications and potential novel risk loci.

BACKGROUND: Association mapping studies of quantitative trait loci (QTL) for canine hip dysplasia (CHD) can contribute to the understanding of the genetic background of this common and debilitating disease and might contribute to its genetic improvement. The power of association studies for CHD is limited by relatively small sample numbers for CHD records within countries, suggesting potential benefits of joining data across countries. However, this is complicated due to the use of different scoring systems across countries. In this study, we incorporated routinely assessed CHD records and genotype data of German Shepherd dogs from two countries (UK and Sweden) to perform genome-wide association studies (GWAS) within populations using different variations of CHD phenotypes. As phenotypes, dogs were either classified into cases and controls based on the Fédération Cynologique Internationale (FCI) five-level grading of the worst hip or the FCI grade was treated as an ordinal trait. In a subsequent meta-analysis, we added publicly available data from a Finnish population and performed the GWAS across all populations. Genetic associations for the CHD phenotypes were evaluated in a linear mixed model using 62,089 SNPs. RESULTS: Multiple SNPs with genome-wide significant and suggestive associations were detected in single-population GWAS and the meta-analysis. Few of these SNPs overlapped between populations or between single-population GWAS and the meta-analysis, suggesting that many CHD-related QTL are population-specific. More significant or suggestive SNPs were identified when FCI grades were used as phenotypes in comparison to the case-control approach. MED13 (Chr 9) and PLEKHA7 (Chr 21) emerged as novel positional candidate genes associated with hip dysplasia. CONCLUSIONS: Our findings confirm the complex genetic nature of hip dysplasia in dogs, with multiple loci associated with the trait, most of which are population-specific. Routinely assessed CHD information collected across countries provide an opportunity to increase sample sizes and statistical power for association studies. While the lack of standardisation of CHD assessment schemes across countries poses a challenge, we showed that conversion of traits can be utilised to overcome this obstacle.

Validation of DNA test for hip dysplasia failed in Danish Labrador Retrievers.

Canine hip dysplasia is characterized by poor hip joint conformation and laxity. The disease is a complex trait influenced by both genetics and environment. Diagnosis and quantification of hip dysplasia are performed by radiographic examination of the hip joint and the diagnosis is used for making breeding decisions in many breeds. A prognostic genetic test (the Dysgen test) based on seven associated SNPs has been developed in a study based on Spanish Labrador Retrievers. In our study this test has been evaluated in 39 Danish Labrador Retrievers with known radiographic hip score: 14 with hip dysplasia (grade D or E) and 25 without hip dysplasia (grade A or B). There was no significant correlation between the Dysgen test results and the radiographic hip status (P = 0.3203) in these dogs, indicating that Dysgen test results obtained for Danish Labrador Retrievers have no prognostic value.

Triple pelvic osteotomy with a 12.5° and a 20° Slocum-type plate: A short-term prospective clinical pilot study in 38 dogs.

OBJECTIVE: To determine whether using 12.5° Slocum-like triple pelvic osteotomy (TPO) plates would create sufficient femoral head coverage and lower the occurrence of overrotation compared with using 20° TPO plates in dogs with hip dysplasia. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Thirty-five dogs with hip dysplasia (38 hips). METHODS: Nineteen hips were surgically treated with a custom-made Slocum-type 12.5° TPO plate, and these were matched to 19 hips surgically treated with a 20° commercial Slocum TPO plate. Hips were case matched according to size and breed. Ortolani sign, angles of subluxation and reduction, distraction index, and femoral head coverage (FHC) were compared between groups. Excessive coverage was defined as >80%. RESULTS: In the 12.5° group, FHC was ≥50% in all hips, with mean FHC (67%), gain (37%), and excessive coverage (11%) all significantly less than in the 20° group (79%, 54%, and 42%, respectively). CONCLUSION: The 12.5° plate produced sufficient FHC compared with the 20° plate, with fewer hips with excessive coverage. CLINICAL SIGNIFICANCE: The 12.5° TPO plate may result in sufficient FHC with a lower occurrence of excessive coverage compared with 20° plates.

Genetic dissection of canine hip dysplasia phenotypes and osteoarthritis reveals three novel loci.

BACKGROUND: Hip dysplasia and osteoarthritis continue to be prevalent problems in veterinary and human medicine. Canine hip dysplasia is particularly problematic as it massively affects several large-sized breeds and can cause a severe impairment of the quality of life. In Finland, the complex condition is categorized to five classes from normal to severe dysplasia, but the categorization includes several sub-traits: congruity of the joint, Norberg angle, subluxation degree of the joint, shape and depth of the acetabulum, and osteoarthritis. Hip dysplasia and osteoarthritis have been proposed to have separate genetic etiologies. RESULTS: Using Fédération Cynologique Internationale -standardized ventrodorsal radiographs, German shepherds were rigorously phenotyped for osteoarthritis, and for joint incongruity by Norberg angle and femoral head center position in relation to dorsal acetabular edge. The affected dogs were categorized into mild, moderate and severe dysplastic phenotypes using official hip scores. Three different genome-wide significant loci were uncovered. The strongest candidate genes for hip joint incongruity were noggin (NOG), a bone and joint developmental gene on chromosome 9, and nanos C2HC-type zinc finger 1 (NANOS1), a regulator of matrix metalloproteinase 14 (MMP14) on chromosome 28. Osteoarthritis mapped to a long intergenic region on chromosome 1, between genes encoding for NADPH oxidase 3 (NOX3), an intriguing candidate for articular cartilage degradation, and AT-rich interactive domain 1B (ARID1B) that has been previously linked to joint laxity. CONCLUSIONS: Our findings highlight the complexity of canine hip dysplasia phenotypes. In particular, the results of this study point to the potential involvement of specific and partially distinct loci and genes or pathways in the development of incongruity, mild dysplasia, moderate-to-severe dysplasia and osteoarthritis of canine hip joints. Further studies should unravel the unique and common mechanisms for the various sub-traits.

Correlation of distraction index with arthroscopic findings in juvenile dogs with hip dysplasia.

OBJECTIVE: To compare distraction index (DI) with hip arthroscopy findings in juvenile dogs with hip dysplasia undergoing unilateral or bilateral double pelvic osteotomy (DPO). STUDY DESIGN: Retrospective case series. ANIMALS: Twenty dogs (36 hip joints). METHODS: Medical records from dogs undergoing unilateral or bilateral DPO (2011-2016) were reviewed. Distraction index was measured by using distraction view radiographs. Arthroscopic images were analyzed. Cartilage was graded by using the modified Outerbridge scale (0 = arthroscopically normal, 1 = chondromalacia, 2 = surface fibrillation, 3 = deep fissuring, 4 = full-thickness cartilage loss, and 5 = eburnation of exposed subchondral bone). Dorsal acetabular rim, acetabular labrum, the ligament of head of the femur, and synovitis were graded by using a four-point scale (normal, mild, moderate, severe). Spearman and Pearson correlations were used to compare DI between grade groups and age. RESULTS: Distraction index ranged from 0.4 to 1.0 (mean 0.69 ± 0.16). Most of the hips had an arthroscopically normal femoral head and acetabulum in most regions, except for the region at the insertion of the ligament of the head of the femur. There was a low positive correlation between synovitis and DI (Spearman ρ = 0.35, P = .0346). No other differences in DI were identified between grade or age groups. CONCLUSION: There was a low positive correlation between synovitis and DI. No other differences in DI were identified. CLINICAL SIGNIFICANCE: Arthroscopic evaluation of the coxofemoral joint prior to DPO can allow detection of joint pathology that might not be appreciated by using traditional radiographic screening criteria.

Total hip arthroplasty to address chronic hip luxation with pseudoacetabulum formation in seven dogs.

OBJECTIVE: To compare the outcome of dogs treated with total hip arthroplasty (THA) for chronic hip luxation and pseudoacetabulum formation to that of dogs with simple hip dysplasia and secondary osteoarthritis. STUDY DESIGN: Retrospective, case-controlled study. ANIMALS: Seven dogs with pseudoacetabulum (group 1) and 21 matched control dogs (group 2). METHODS: Each dog in group 1 was matched with three control dogs, primarily according to similarity of THA implant type and size. Patterns of radiographic pathology were characterized in each dog. Outcome measures included operative time, acetabular cup position/orientation (inclination angle, angle of lateral opening, version angle) complications, and long-term outcomes. Outcome measures were compared between groups using linear regression (P = .05). RESULTS: The presence of a pseudoacetabulum was associated with ilial remodeling and heterotopic bone formation concentric to the luxated femoral head. Exposing the native acetabulum and reducing the prosthesis were surgically challenging. The mean (SD) operative time of dogs in group 1 (96 [18] minutes) was longer than that of dogs in group 2 (63 [14] minutes; P = .00002). Cup position/orientation was not different between dogs in group 1 and group 2. One intraoperative complication and two minor postoperative complications occurred in group 1 dogs. All dogs had good long-term outcomes. CONCLUSION: Total hip arthroplasty in dogs with a pseudoacetabulum was more challenging than in control dogs. However, the procedure provided good to excellent long-term clinical outcomes in all dogs. CLINICAL SIGNIFICANCE: Surgeons should be prepared for the specific surgical challenges associated with THA in dogs with pseudoacetabulum formation.

Preventing skeletal and neurological problems in guide dogs for the blind and other working dogs.

Skeletal and neurological problems consistently rank among the top health conditions necessitating the withdrawal or retirement of guide dogs and other working dogs from their service roles. Management practices such as weight management and physical conditioning may help to reduce the incidence of such conditions. However, where there is at least partial genetic aetiology, selective breeding strategies are the only way to produce a lasting reduction in their incidence in future generations. The management of single gene disorders is relatively simple through the judicious use of DNA test results. Breeding strategies to tackle complex diseases, into which category many skeletal and neurological diseases fall, are more challenging but can be successful through the use of data collected through screening schemes and, most efficiently, through the use of estimated breeding values.

Les troubles squelettiques et neurologiques comptent parmi les principaux problèmes de santé imposant la réforme ou la mise à la retraite des chiens guide d'aveugles et autres chiens de travail. Certaines pratiques de bonne gestion veillant notamment à contrôler le poids et la condition physique des chiens peuvent contribuer à réduire l'incidence de ce type de problèmes. Toutefois, lorsque l'étiologie des problèmes de santé est totalement ou partiellement déterminée par la génétique, les stratégies de sélection constituent le seul moyen de réduire durablement cette incidence pour les générations futures. La gestion de certains troubles dus à un gène unique est relativement aisée, grâce à un emploi judicieux des résultats de tests ADN. Lorsqu'il s'agit de maladies plus complexes, catégorie recouvrant nombre d'infections squelettiques et neurologiques, les stratégies de sélection sont plus difficiles à mettre en oeuvre mais elles peuvent réussir si l'on procède à une collecte de données via des dispositifs de dépistage, ou en recourant aux valeurs d'élevage estimées, qui déterminent encore plus efficacement le potentiel génétique d'un chien.

Los problemas esqueléticos y neurológicos se sitúan sistemáticamente entre las principales dolencias que hacen necesario retirar o jubilar a los perros lazarillos y otros perros de trabajo de las tareas que cumplen al servicio del ser humano. Hay procedimientos de gestión, como la regulación del peso o el condicionamiento físico, que pueden ayudar a reducir la incidencia de este tipo de trastornos. Sin embargo, en los casos en que hay, cuando menos parcialmente, una etiología genética, las estrategias de cría selectiva son el único modo de conseguir una reducción duradera de su incidencia en las generaciones futuras. La gestión de trastornos ligados a un solo gen es relativamente sencilla, pues pasa por un uso juicioso de los resultados de las pruebas de ADN. Las estrategias de cría selectiva para combatir enfermedades complejas, categoría en la que entran muchas enfermedades esqueléticas y neurológicas, plantean mayor dificultad, pero pueden deparar buenos resultados cuando se utilizan datos obtenidos con programas de cribado sistemático y ser de lo más eficaces cuando se aplican empleando valores estimados de cría.

A veterinary perspective on preventing injuries and other problems that shorten the life of working dogs.

Domesticated dogs are widely used for farm work, law enforcement, military service and in assistance roles. Farm dogs assist farmers by guarding or moving stock, reducing the requirement for human workers and enabling steep terrain to be productive. Working and service dogs are subject to illness and injury, depending on their breed characteristics, activities and the environment in which they work. There are limited data in the veterinary literature on the causes of loss and early retirement of working dogs, and targeted research is required to better determine factors that affect their incidence. Many breeds of working dog suffer from inherited forms of musculoskeletal disease; most importantly, elbow and hip dysplasia. The effectiveness of traditional radiographic (phenotypic) scoring schemes at reducing the prevalence of hip and elbow dysplasia has been variable. The selection of breeding stock should preferably be based on estimated breeding values, rather than on an individual phenotypic score/grade. Nutrition can affect physical and mental performance, disease risk and susceptibility, and recovery from injury, age-associated decline and longevity. The dietary proportions of fat, protein and carbohydrate influence fuel selection during exercise. A common concern among farmers is the difficulty of maintaining body condition in their dogs during periods of heavy work with current feeding practices. Additionally, maintaining a positive calcium balance is necessary for adaptive remodelling in response to exercise. Research strategies should include improved treatment options, the development of more specific means of genetic selection for inherited diseases, investigation into specific nutritional requirements and the dissemination of this knowledge.

Les chiens domestiqués sont très largement utilisés pour travailler dans les fermes, ainsi qu'en tant que chiens policiers, chiens militaires ou chiens d'assistance. Les chiens de ferme aident les éleveurs à garder ou à déplacer leurs troupeaux, ce qui réduit les besoins en main d'oeuvre et permet d'exploiter des terrains escarpés. Les chiens de travail et aidants sont plus ou moins exposés à la maladie et aux blessures, en fonction des caractéristiques de leur race, des tâches qui leur sont confiées et de l'environnement dans lequel ils travaillent. Il n'existe pas beaucoup d'études vétérinaires publiées sur les causes des morts et des mises à la retraite prématurées des chiens de travail, thème qu'il conviendrait d'explorer plus précisément afin de mieux déterminer les facteurs affectant l'incidence de ces problèmes. Plusieurs races canines sont atteintes de troubles musculo-squelettiques héréditaires, dont le plus important est la dysplasie du coude et de la hanche. Les méthodes traditionnelles d'interprétation radiologique (mesure des phénotypes) ont contribué à réduire la prévalence de la dysplasie du coude et de la hanche, avec des résultats variables. La sélection des reproducteurs devrait reposer sur l'estimation de leur potentiel génétique (valeur d'élevage) plutôt que sur le score ou l'échelle de mesure du phénotype d'un individu. L'alimentation joue un rôle sur les performances physiques et mentales, la sensibilité aux maladies et le risque sanitaire, les capacités de rétablissement après une blessure, le processus de vieillissement et la longévité. La proportion relative des lipides, protéines et glucides dans l'alimentation donnée aux chiens détermine les sources d'énergie utilisées durant l'effort. Une préoccupation courante parmi les éleveurs concerne la difficulté de maintenir leurs chiens en bonne condition physique pendant les périodes où le travail est le plus dur, compte tenu des pratiques d'alimentation actuelles. Il est également important de maintenir un bon équilibre en calcium afin de soutenir les capacités d'adaptation à l'effort et de récupération. Les stratégies de recherche devraient explorer les pistes d'amélioration des traitements, mettre au point des méthodes de sélection génétique axées spécifiquement sur les maladies héréditaires et mieux élucider les besoins nutritionnels des chiens, sans oublier de diffuser par la suite les connaissances ainsi obtenues.

El uso del perro doméstico en tareas agrícolas, policiales, militares y de socorro o ayuda está muy extendido. Los perros pastores ayudan al granjero vigilando o conduciendo el ganado, lo que reduce la necesidad de personal humano y permite aprovechar las tierras situadas en terrenos escarpados. Los perros de trabajo y de servicio están sujetos a enfermedades y lesiones que dependen de las características de la raza, la actividad de que se trate y el medio en que esta discurra. En la bibliografía veterinaria hay escasa información sobre las causas que subyacen a la pérdida o la jubilación anticipada de perros de trabajo. De ahí la necesidad de investigar específicamente este aspecto para determinar con más precisión los factores que influyen en ello. Muchas razas de perros de trabajo padecen formas hereditarias de enfermedad musculoesquelética, la más importante de ellas la displasia de codo o cadera. Los tradicionales sistemas de puntuación radiológica (fenotípica) han resultado de eficacia variable para reducir la prevalencia de estas dos displasias. La selección de ejemplares reproductores debería basarse no tanto en la puntuación o grado fenotípico de cada individuo como en los valores estimados de cría. La alimentación puede influir en el rendimiento físico y mental, el riesgo de enfermedades y la sensibilidad a ellas, la recuperación tras una lesión y la longevidad o la decadencia ligada a la edad. Las proporciones de grasas, proteínas y carbohidratos presentes en el régimen alimentario influyen en la selección de combustible metabólico durante la actividad física. Uno de los aspectos que preocupa a todos los granjeros es la dificultad de mantener el cuerpo del perro en condiciones en los periodos de mucho trabajo con las actuales prácticas de alimentación. Además, también es necesario mantener un saldo positivo de calcio para que tenga lugar la remodelación adaptativa del cuerpo en respuesta al ejercicio físico. Los planes de investigación deben incluir aspectos como la búsqueda de mejores alternativas de tratamiento, la obtención de medios más específicos de selección genética respecto de las enfermedades hereditarias, el estudio de necesidades nutricionales específicas y la difusión de cuanto conocimiento resulte de estas investigaciones.

Management of total hip replacement luxation with triple pelvic osteotomy.

OBJECTIVE: To report the outcome of dogs treated with triple pelvic osteotomy (TPO) for dorsal luxation after total hip replacement (THR). STUDY DESIGN: Retrospective clinical case series. ANIMALS: Seventeen client-owned animals. METHODS: Medical records were searched at a single institution for dogs that had been treated with TPO for dorsal THR luxation. The angle of lateral opening (ALO), version angle (VA), and inclination angle (IA) were measured from radiographs after THR and TPO and corrected for pelvic rotation. A paired t test was performed to compare cup orientation after THR and TPO. Functional outcome was assessed at follow-up examination and during telephone interviews. RESULTS: Eighteen TPOs were performed in 17 dogs, and radiographs were available for 15 cases. Open and/or closed hip reduction with additional stabilization was attempted unsuccessfully in 6 dogs prior to TPO. Triple pelvic osteotomy reduced the ALO by a mean of 23.0 ° ± 10.9 ° (P ≤ .001), increased VA by 9.0 ° ± 4.9 ° (P < .001), and increased IA by 2.9 ° ± 5.8 ° (P = .126). An excellent or good outcome was achieved in 12 dogs. Ventral luxation occurred in 3 dogs, and dorsal luxation occurred in 1 dog after TPO. Triple pelvic osteotomy excessively reduced ALO in 2 dogs with ventral luxation. CONCLUSION: Triple pelvic osteotomy with cup retention is a viable alternative to cup revision for treatment of dorsal luxation of cemented and cementless THR. Triple pelvic osteotomy significantly reduces ALO and increases VA. Careful patient selection is recommended because excessive ventroversion can lead to ventral luxation. CLINICAL SIGNIFICANCE: Triple pelvic osteotomy offers a revision option that preserves the implant-bone interface and significantly reduces ALO. This technique may be appropriate in dogs with high ALO, luxoid hips, and prior failed revision attempts.

Heritabilities and genetic trends for elbow score as recorded by the New Zealand Veterinary Association Elbow Dysplasia Scheme (1992-2013) in four breeds of dog.

AIM: To estimate the heritability of the New Zealand Veterinary Association (NZVA) elbow phenotype, obtain estimated breeding values (EBV) for the worst-elbow score and estimate the genetic trends for this trait in four populous breeds of dogs, using the records from the NZVA Canine Elbow Dysplasia Scheme database (1992-2013). METHODS: Overall, 4,070 elbow records from a pedigree of 11,311 dogs were available for animals scored between 1992 and 2013. The worst elbow score between the left and right elbows was identified for each dog and used for EBV analysis. Estimates of heritability and EBV for the elbow score of dogs from German Shepherd dog, Labrador Retriever, Golden Retriever and Rottweiler breeds were obtained using restricted maximum likelihood procedures with a within-breed linear animal model. The model included the fixed effects of sex and birth year, with age at scoring as a covariable, and the random effect of animal. Genetic trends for the worst-elbow score were calculated as the regression coefficient of the EBV, weighted by reliabilities, on year of birth. RESULTS: The estimates of heritability for worst-elbow score were 0.25 (SE 0.06) in German Shepherd dogs, 0.46 (SE 0.06) in Labrador Retrievers, 0.18 (SE 0.07) in Golden Retrievers and 0.29 (SE 0.11) in Rottweilers. The genetic trend for German Shepherd dogs was -0.0082 (SE 0.0015), for Labrador Retrievers was -0.0016 (SE 0.0016), for Golden Retrievers was -0.0033 (SE 0.0010) and for Rottweilers was -0.0070 (SE 0.0023) units per annum, which were different from zero (p<0.01) in all breeds except Labrador Retrievers. CONCLUSIONS AND CLINICAL RELEVANCE: A small but favourable response to selection was achieved by three of the four breeds in the study period; during which selection for elbow traits has been largely voluntary. While the magnitude of genetic change in terms of elbow units per annum may appear small, it must be remembered that elbow scoring grades only range from 0-3. Greater improvement may be possible if compulsory screening was a requirement for pedigree breeding stock, and if greater selection pressure were applied on the basis on an individual's EBV, rather than the worst-elbow score alone. The maintenance of an open registry, with transparency of EBV information made available to all breeders, may enhance selection intensity opportunities and potentially assist with the process and progress of breeding selection.

Provisional heritability estimates of four distraction index traits in a breeding population of German Shepherd dogs.

AIM To obtain provisional estimates of the heritability (h2 ) of passive laxity of the coxofemoral joints of a breeding colony of German Shepherd dogs, measured using the PennHIP distraction index (DI). METHODS Records were obtained of the PennHIP DI of right and left hips of 195 German Shepherd dogs (377 DI records) from the dog breeding colony of the New Zealand Police Dog Breeding Centre between 2003 and 2016, as well as pedigree records of 884 animals over four generations. Estimates of h2 and variance components for the log transformed DI data were obtained using restricted maximum likelihood procedures with a single trait sire model. Four DI traits for each dog were analysed: left hip, right hip, mean and worse-hip DI. The model included the fixed effects of sex and year of birth, with the age at scoring as a covariable, the random sire effect and residual error for each observation. RESULTS The h2 of the DI of the left hip (0.81, SE 0.40) was higher than the h2 of the DI of the right hip (0.35, SE 0.36). The h2 for the worse-hip DI (0.15, SE 0.28) in each dog was lower than the h2 of the individual hip DI, or the h2 for the mean of the two hips (0.53, SE 0.36) in each dog. The low number of generations prevented a meaningful analysis of the genetic trend. CONCLUSIONS AND CLINICAL RELEVANCE The h2 estimates for the left, right and mean DI traits were moderate to high, whereas the h2 estimates for the worse-hip DI (as used by the PennHIP programme for ranking of dogs) was low, but all estimates had large SE due to the small sample size. This provisional estimate of the h2 of four distraction index traits suggests that the mean DI could be useful as a selection tool against canine hip dysplasia in German Shepherd dogs, whereas the worse-hip DI may be less effective. Heritability estimates from a population with a greater number of DI measures is needed to validate this finding given the large SE in our study.

Intra- and interobserver agreement on radiographic phenotype in the diagnosis of canine hip dysplasia.

OBJECTIVE: To investigate the repeatability and reproducibility of the presence of a circumferential femoral head osteophyte (CFHO), a curvilinear caudolateral osteophyte (CCO), osteosclerosis of the cranial acetabular edge (Scler CrAE), degenerative joint disease (DJD), and the diagnosis of suspected canine hip dysplasia (CHD) in different groups of experienced observers. STUDY DESIGN: Cross-sectional study. SAMPLE POPULATION: Standard hip extended radiographs (n = 50). METHODS: Nine experienced observers were divided into 3 groups: surgeons (DECVS), radiologists (DECVDI), and non-board certified observers (NBC) and 2 subgroups (academics and non-academics). Cohen's kappa (κ) was calculated for CFHO, CCO, Scler CrAE, DJD, and suspected CHD, and weighted κ was calculated for DJD score to determine inter- and intraobserver agreement. RESULTS: Intraobserver agreement on CFHO, CCO, Scler CrAE, DJD, and suspected CHD ranged from slight to almost perfect, but was not significantly different between NBC, DECVS, and DECVDI. Radiologists and non-board certified observers had a more uniform scoring than surgeons on the overall DJD score, as did academics versus non-academics. Interobserver agreement for NBC was more uniform than that of radiologists and surgeons on CCO and DJD. NBC and radiologists scored more uniformly than surgeons on CFHO, and radiologists scored more uniformly than NBC and surgeons on Scler CrAE. Academics scored more uniformly than non-academics, but only significantly for Scler CrAE. CONCLUSIONS: Recognition of specific radiographic markers is only fairly reliable within and between experienced observers. Therefore, care must be taken to apply these traits in official screening, surgical decision-making and scientific research.