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.

Lumbosacral transitional vertebra in 14 dog breeds in Norway: Occurrence, risk factors and association with hip dysplasia.

A lumbosacral transitional vertebra (LTV) is a congenital anomaly of the spine and has been suggested to predispose to canine hip dysplasia (CHD). This retrospective, cross-sectional study investigated the prevalence of LTV and CHD among 14 dog breeds in Norway, the possible associations with risk factors, and whether LTV was a risk factor for the development of hip dysplasia. The results were based on evaluation of ventrodorsal radiographs from the CHD screening program from the Norwegian Kennel Club from February 2014 to January 2022. A total of 13,950 dogs were included in the study. For statistical analysis, CHD grades were reclassified from the official Federation Cynologique Internationale (FCI) grades into three grades: CHD free (CHD=A, B), CHD mild (CHD=C), and CHD severe (CHD=D, E). In the study sample, the overall occurrence of LTV was 18.5%, of which 32.9% were type 1, 45.7% type 2% and 21.4% type 3. The occurrence of LTV varied significantly among the included breeds, ranging from 9.5% to 46.2%. There was no association between sex and LTV. The frequencies of CHD grades were A: 43.1%; B: 31.4%; C: 18.4%; D: 6.0%; E: 1.1%. There was a statistically significant association with mild and severe CHD in dogs with LTV type 2 and LTV type 3 (P< 0.001). In the population studied, the prevalence of LTV was different among breeds. This supports initial data on the heredity of LTV and the diverse occurrence of LTV among breeds. Our results indicate that LTV type 2 and type 3 are associated with mild and severe CHD development. Therefore, this study has potentially identified an additional risk factor for the development of hip dysplasia.

Quantifying the Stress in Stress Radiographs to Determine Sufficient Laxity of the Coxofemoral Joint: A Canine Hip Dysplasia Cadaveric Study.

OBJECTIVE: While it has been known for a long time that laxity in the hip joint is the primary cause of degenerative changes later on in canine hip dysplasia, limited data are available on the fundamental characteristics that define the procedure used to quantify this. The aim of this study was to evaluate the force-laxity relation to assess the repeatability of repeated cycles of stress on the hip joint and determine the force necessary tomeasure a sufficient proportion of laxity present in hip joints. MATERIALS AND METHODS: Thirty-four canine cadavers underwent a radiographic protocol including stress radiographs with increasing force using the Vezzoni modified Badertscher distension measuring device (VMBDmD). Three dogs underwent five repeat examinations. The laxity index (LI) and osteoarthritis were scored. RESULTS AND CONCLUSION: The curves and the maximal LI (LImax) were not significantly influenced by osteoarthritis, weight, gender, and side. The position of the VMBDmD influenced the curve but not the LImax. The force-laxity curve itself and the LImax were repeatable, which indicated that it did not cause permanent damage to the joint and also confirmed the practicability of the procedure. Ninety percent of hip joints reached sufficient laxity at a force of 95.32 N, which is realistically achievable. Further studies are necessary before extrapolating these results to patients and to further enlighten the biomechanics of stress radiographs.

Influence of Femoral Position and Pelvic Projection on Norberg Angle Measurements.

OBJECTIVE: Canine hip dysplasia is a common orthopaedic disease in dogs. The Norberg angle value is a measure of hip joint laxity. The aim of this study was to quantify the degree of rotation necessary to consider the radiograph as inadequately positioned and to determine the influence of rotation on the Norberg angle. STUDY DESIGN: Three sets of radiographs with different positioning and projections were acquired using 10 canine cadavers. Rotation of the pelvis was simulated by rotating the X-ray tube without changing the position of the patient. RESULTS: In dorsoventral projections, the Norberg angle value is increased by 3.2 to 5.8%. Due to rotation along the long axis, the Norberg angle increases on one side and decreases on the contralateral side by approximately the same value. Rotation of greater than 2 degrees in a lateral direction is visually perceived by the observer as tilted. Rotation of the projection in the caudoventral to craniodorsal direction causes mild increase of the Norberg angle (≤1%), while rotation of the projection in a cranioventral to caudodorsal direction causes moderate (≤2%) decrease of the Norberg angle. Rotation of less than -10 degrees (caudoventral to craniodorsal) or greater than 10 degrees (cranioventral to caudodorsal) is visually perceived as tilted. CONCLUSION: Tilted images that are subjectively perceived evaluable have only little effect on the Norberg angle and are therefore probably acceptable. Dorsoventral projections can be recognized based on the proximal position of the patella and should be excluded from evaluation, as the Norberg angle value can be falsely increased.

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.

Breed-specific evaluation of serum biochemical markers in canine hip dysplasia observed in a Tornjak dog population.

OBJECTIVE: Canine hip dysplasia (CHD) is a global disease and an improved diagnostic approach to this orthopedic condition is needed, with an emphasis on inexpensive and minimally invasive techniques. This research aimed to determine the differentiating potential of selected biochemical markers in serum between healthy dogs and dogs with hip dysplasia in a breed-specific study that involved the Tornjak dog population. ANIMALS: 99 Tornjak dogs radiographically categorized (Federation Cynologique Internationale procedure and scoring scheme) between December 2019 and April 2021, as having no sign of hip dysplasia or near normal hip joints (nondysplastic group; n = 51) vs mild, moderate, or severe hip dysplasia (dysplastic group; 48). METHODS: Serum concentrations and enzyme activity of the biochemical markers hyaluronic acid (HA), procollagen II C-terminal propeptide (PIICP), and metalloproteinase 9 (MMP9) were compared among adult dogs with or without radiographic hip dysplasia. Statistical tests used to examine the differentiating potential of biochemical markers in Tornjak dog groups were assessed using the Mann-Whitney U test, logistic regression, and receiving operating characteristics (ROC) analysis. RESULTS: Tornjak dogs with radiographic CHD had significantly lower serum concentrations of HA and higher concentrations of PIICP and MMP9 activity compared to dogs with radiographically normal hips (P < .05). Selected biochemical markers could distinguish dogs with radiographic CHD from those without CHD with high sensitivity and specificity. CLINICAL RELEVANCE: These data suggest that the diagnostic technique of measuring serum concentrations of HA, PIICP, and MMP9 activity has a selective ability to distinguish dogs with dysplastic from dogs with normal hips.

Preliminary transcriptomic analysis of peripheral blood from German Shepherd dogs with degenerative joint disease for the identification of diagnostic biomarkers.

OBJECTIVE: Degenerative joint disease (DJD) includes a group of disorders characterised by the deterioration of the articular cartilage. In this study, we investigated the transcriptomic profile of peripheral blood in German Shepherd dogs with DJD to identify putative diagnostic biomarkers. METHODS: Differential gene expression (DGE) and gene ontology (GO) analyses of the bulk RNA-seq experiment were performed in a cohort of 12 adult dogs (five cases and seven controls, classified by clinical and radiographic analyses). RESULTS: Radiographs of cases revealed severe signs of progressive DJD. Two up-regulated (LOC106559672 and THBS4) and one down-regulated (LOC106559235) differentially expressed genes (adjusted p value < 0.05) were identified. The DGE with log2 fold change < -1.5 and > 1.5 and non-adjusted p < 0.01 were selected for GO analysis. No significant enrichment terms were observed in the selected threshold. CONCLUSION: The gene-encoding protein THBS4 is correlated with DJD severity and long noncoding RNA LOC106559235 is probably involved in the DJD process. The THBS4 gene should be considered a good biomarker for DJD in dogs. Future studies using independent cohorts will be necessary to validate the present results.

Development and validation of a device to measure the force applied to the coxofemoral joint during stress radiography for early diagnosis of canine hip dysplasia.

Hip dysplasia is a common orthopaedic condition in dogs and stress radiography is the best diagnostic tool for early diagnosis. Objective force guidelines are lacking, leaving room for errors and fraud during screening. Our objective was to develop an accurate and validated measuring device that allows quantification of the applied force in vivo in real-time during stress radiographic imaging. A two-step approach was followed. First, four load cells were incorporated in the original Vezzoni Modified Badertscher Distension Device (VMBDD) and a dedicated computer program was developed. In vitro evaluations of the accuracy demonstrated a trueness of 0.19 N (0.1%FS) and precision of 0.26 N (0.2%FS) for the individual loadcells. The trueness and precision of the assembled VMBDmD were 0.02 N (0.02%FS) and 0.52 N (0.38%FS). Secondly, the modified device was tested on several cadavers. The device was similar in use as the VMBDD, did not interfere with radiographic acquisition, gave the operator real-time feedback, and linked the force with the radiograph. Altogether, we describe the accuracy of the VMBDmD and have evaluated its use in cadavers. We saw that the device successfully quantified and stored the applied force in real-time during stress radiography.

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.

Imaging diagnosis of canine hip dysplasia with and without human exposure to ionizing radiation.

Hip dysplasia (HD) is one of the most common hereditary orthopaedic diseases in dogs, with serious implications for the quality of life of the affected animals. Radiographic screening is essential for the selection of breeding stock in some at-risk breeds, and radiography is also used in the diagnosis of clinical HD cases. A definitive diagnosis of HD is based on radiographic examination, and the most commonly used view is the ventrodorsal hip extended projection, sometimes in combination with various hip stress-based techniques. Radiographic images require high quality positioning and dogs are usually anesthetized and often manually restrained to facilitate optimal positioning. The 'as low as reasonably achievable' (ALARA) principle used in human radioprotection is not always fulfilled in veterinary practice, except in the UK, where human exposure to ionizing radiation in veterinary medicine is strictly regulated. While each dose of ionizing radiation is small, doses accumulate over a lifetime, which can eventually result in substantial radiation exposure. Therefore, manual restraint should be avoided and mechanical immobilization, sedation or general anaesthesia should be used. This review examines the biological effects of human exposure to ionizing radiation and common sources of veterinary exposure. The diagnostic quality of imaging methods for the diagnosis of canine HD is compared between manually restrained and hands-free dog positioning. Hands-free radiographic techniques are available to assess hip laxity, degenerative joint changes and hip osseous structure while preserving image quality, and can be used to select animals for breeding or for the diagnosis of HD.

Joint laxity in canine hip dysplasia assessed using the hip flexed not distracted ventrodorsal view.

OBJECTIVES: The ventrodorsal hip extended standard view is conventionally used for radiographic screening of canine hip dysplasia. However, because the ventrodorsal hip extended standard view minimises hip joint laxity, several alternative views have been proposed. Our aim was to evaluate a new ventrodorsal hip flexed and not distracted view to assess joint laxity, by comparing it with the ventrodorsal hip extended standard and ventrodorsal hip flexed and distracted views. MATERIALS AND METHODS: Between April 2013 and March 2017, all dogs referred to the University of Naples "Federico II" for the diagnosis of canine hip dysplasia were studied using the ventrodorsal hip extended standard, ventrodorsal hip flexed and not distracted and ventrodorsal hip flexed and distracted views. The Norberg angle and the laxity index were measured for each view. RESULTS: Overall, 102 dogs, 67 males and 35 females, mean age 15 months, were included. The mean (±standard deviation) Norberg angles were 99.77° (±10.42°), 89.29° (±14.32°) and 91.80° (±13.50°) for the ventrodorsal hip extended standard, ventrodorsal hip flexed and not distracted and ventrodorsal hip flexed and distracted views, respectively. The mean (± standard deviation) laxity indices were 0.19 (± 0.14), 0.39 (± 0.25) and 0.36 (± 0.21), respectively. The ventrodorsal hip flexed and distracted and ventrodorsal hip flexed and not distracted views had lower Norberg angle and higher laxity index values compared with the ventrodorsal hip extended standard view. The ventrodorsal hip flexed and distracted and ventrodorsal hip extended standard views are in strong agreement for the measurement of both Norberg angle and laxity index, as confirmed by Bland-Altman analysis and the intraclass correlation coefficient. CLINICAL SIGNIFICANCE: The ventrodorsal hip flexed and distracted and ventrodorsal hip flexed and not distracted views obtained with the hip in a neutral position reveal joint laxity better than the ventrodorsal hip extended standard view. Unlike the ventrodorsal hip flexed and distracted view, the ventrodorsal hip flexed and not distracted view does not require human operators or special devices for positioning the dog. The wide age range of the dogs enrolled might have influenced the laxity index measurements, since capsular fibrosis in older dogs reduces laxity.

Distraction index and Norberg angle to distinguish dysplastic and non-dysplastic hips based on FCI score.

OBJECTIVE: Radiographic hip scoring according to the Fédération Cynologique Internationale (FCI) and PennHIP (Pennsylvania Hip Improvement Program) method was performed with the purpose to compare the PennHIP and FCI results as well as coxofemoral joint laxity by correlation of Norberg angle and distraction index measurements. MATERIALS AND METHODS: A total of 167 dogs of various breeds presented for official screening examination in a veterinary teaching hospital in Germany were included. Using receiver operating characteristic analysis, the best Norberg angle and distraction index cut-off values to distinguish between dysplastic and non-dysplastic groups based on FCI grades and to distinguish between lax and tight hip joints according to the PennHIP proposal were calculated. RESULTS: More than one third (38.2 %) of dogs that passed the breeding criterions according to FCI (grades A and B) were in the half of the population with lax hip joints and should not be used for breeding according to the PennHIP proposal. A cut-off value for the distraction index of 0.44 with sensitivity of 82.7 % and specificity of 84.2 % was superior to the best cut-off value for the Norberg angle at 101.8° with sensitivity of 82.7 % and specificity of 71.9 % to discriminate between non-dysplastic joints (A, B) and dysplastic joints (C, D, E). CONCLUSIONS AND CLINICAL RELEVANCE: Our results show a limited impact of laxity on the FCI grading. Breeding selection processes that are based on the FCI method could profit by an additional and complementary use of the distraction index.

Prevalence of canine hip dysplasia in 10 breeds in France, a retrospective study of the 1997-2017 radiographic screening period.

Canine hip dysplasia (HD) is a complex developmental disease of the coxo-femoral joint and is one of the most common orthopedic conditions in dogs. Due to the genetic contribution, most of the programs fighting against HD recommend selective breeding that excludes affected dogs. Using the best-scoring dogs for breeding may reduce the prevalence of HD. In France, the phenotypic screening of coxo-femoral joint conformation remains a strategy for breeders to establish selection decisions. The HD prevalence was evaluated in 10 breeds, based on the assessment of 27,710 dogs, during the 1997-2017 screening period, which was divided into 3 homogeneous cohorts for analysis. The global HD prevalence varied widely among breeds from 5% (Siberian Husky) to 51.9% (Cane Corso). It decreased over time in 6 breeds, among which 4 (Cane Corso, Gordon Setter, Rottweiler and White Swiss Shepherd) showed a significant decrease. A statistically significant increase in HD prevalence was noted for the Siberian Husky. Although the efficacy of phenotype-based breeding programs remains controversial, our results are in accordance with several recent studies showing that long-term selection policies are valuable, as they may help decreasing the HD prevalence in some breeds. The complementary use of more recent tools such as estimated breeding values and genomics would probably help breeders achieve more substantive results.

Effectiveness of PennHIP and Orthopedic Foundation for Animals measurements of hip joint quality for breeding selection to reduce hip dysplasia in a population of purpose-bred detection dogs.

OBJECTIVE: To examine the effectiveness of applying selective pressure to improve hip joint quality in purpose-bred detection dogs by use of PennHIP distraction index (DI) values along with Orthopedic Foundation for Animals (OFA) hip joint scores and to determine whether age, sex, coat color, breed, and body weight were associated with hip joint quality. ANIMALS: 615 purpose-bred detection dogs assessed for hip joint quality. PROCEDURES: Orthopedic records of 615 purpose-bred detection dogs (569 Labrador Retrievers and 46 Labrador Retriever-German Wirehaired Pointer crossbred dogs) from 2000 through 2017 were analyzed. From 2000 to 2014, hip joint quality scores were determined by OFA evaluation only (429 dogs). Beginning in 2015, both PennHIP and OFA evaluations were used to select male and female breeding stock (179 dogs; 7 dogs were removed from analysis because they did not undergo both evaluations). Selection threshold DI value for sires and dams was ≤ 0.30; all had hip joint scores of excellent or good by OFA standards. Standard ventrodorsal hip joint-extended and stress (compression and distraction) pelvic radiographs were submitted for OFA and PennHIP evaluations. RESULTS: Hip joint quality scores were unchanged by use of OFA measurements only. When both PennHIP and OFA measurements were used for the selection of breeding stock, hip joint quality scores improved significantly. Sex and age were significant predictors of DI values. CONCLUSIONS AND CLINICAL RELEVANCE: PennHIP DI values were an effective measurement of hip joint quality for selecting breeding stock, and the addition of DI values to OFA measurements significantly improved hip joint quality in a population of purpose-bred dogs.

3D printing of canine hip dysplasia: anatomic models and radiographs / Impressão 3D da displasia coxofemoral canina: modelos anatômicos e radiografias

Canine Hip Dysplasia (CHD) is a highly prevalent articular pathological condition. In this sense, radiography becomes an important diagnostic method to determine the presence and severity of the disease. The objective was to create 3D models and their respective radiographs representing the CHD (3D AMCHD). The research was carried out in the Laboratory of 3D Educational Technologies of UFAC, under no. 23107.007273/2017-49 (CEUA/UFAC). A canine skeleton (hip bone, femurs and patellae) was used without anatomical deformities compatible with DCF (pelvis, femurs and patella), which were scanned in order to obtain the files of the base model. In these files the deformations representing the different degrees of CHD were performed. Subsequently, the 3D AMCHD files were printed, mounted and X-rayed. The 3D AMCHD represented the bone deformations of the different degrees of CHD. In the radiographs of the 3D AMCHD it was possible to observe and determine each of the bones that constituted the hip joints. This allowed to reproduce the correct positioning to represent the CHD diagnosis and establish the precise points to determine the Norberg angle. In this way, it was evidenced that the 3D AMCHD can be a possible tool to be used in the Teaching of Veterinary Medicine.(AU)

A displasia coxofemoral canina (DCF) é uma condição patológica articular de grande prevalência. Nesse sentido, a radiografia torna-se um método de diagnóstico importante para determinar a presença e a gravidade da doença. O objetivo do presente trabalho foi criar modelos 3D e suas respectivas radiografias representando a DCF (MADCF 3D). A pesquisa foi realizada no Laboratório de Tecnologias Educacionais 3D da UFAC, sob o nº. 23107.007273/2017-49 (Ceua/Ufac). Foram utilizados esqueletos caninos (pelve, fêmures e patelas) sem deformidades anatômicas compatíveis com a DCF, os quais foram digitalizados a fim de se obterem os arquivos do modelo base. Nesses arquivos foram realizadas as deformações que representavam os diferentes graus da DCF. Posteriormente, os arquivos dos MADCF 3D foram impressos, montados e radiografados. Os MADCF 3D representaram as deformações ósseas dos diferentes graus da DCF. Nas radiografias dos MADCF 3D, foi possível observar e determinar cada um dos ossos que constituíam as articulações coxofemorais. Isso permitiu reproduzir o posicionamento correto para representação do diagnóstico DCF e estabelecer os pontos precisos para determinar o ângulo de Norberg. Dessa forma, evidenciou-se que os MADCF 3D podem ser uma possível ferramenta a ser empregada no ensino de medicina veterinária.(AU)

Comparison of Reliability of Norberg Angle and Distraction Index as Measurements for Hip Laxity in Dogs.

OBJECTIVE: The main purpose of the study was to compare reliability of measurements for the evaluation of hip joint laxity in 59 dogs. MATERIALS AND METHODS: Measurement of the distraction index (DI) of the PennHIP method and the Norberg angle (NA) of the Fédération Cynologique Internationale (FCI) scoring scheme as well as scoring according to the FCI scheme and the Swiss scoring scheme were performed by three observers at different level of experience. For each dog, two radiographs were acquired with each method by the same operator to evaluate intraoperator-reliability. RESULTS: Intraoperator-reliability was slightly better for the NA compared with the DI with an intraclass correlation coefficient (ICC) of 0.962 and 0.892 respectively. The ICC showed excellent results in intraobserver-reliability and interobserver-reliability for both the NA (ICC 0.975; 0.969) and the DI (ICC 0.986; 0.972). Thus, the NA as well as the DI can be considered as reliable measurements. The FCI scheme and the Swiss scoring scheme provide similar reliability. While the FCI scheme seems to be slightly more reliable in experienced observers (Kappa FCI 0.687; Kappa Swiss 0.681), the Swiss scoring scheme had a noticeable better reliability for the unexperienced observer (Kappa FCI 0.465; Kappa Swiss 0.514). CLINICAL SIGNIFICANCE: The Swiss scoring scheme provides a structured guideline for the interpretation of hip radiographs and can thus be recommended to unexperienced observers.

Influence of Anesthesia on Grading of Canine Hip Dysplasia.

This study aimed to evaluate the effect of anesthesia on grading of canine hip dysplasia. For this purpose, 20 middle-sized healthy dogs from different breeds were used. Radiographs were taken using 4 different imaging methods, including the hip-extended, subluxation, distraction, and compression. This procedure was repeated 4 times for each dog, while the dogs were unanesthetized and anesthetized with 3 different anesthetic protocols at 15-day intervals (propofol [5 mg/kg, IV]; diazepam [0.5 mg/kg, IV] / ketamine [20 mg/kg, IV]; medetomidine [0.05 µg/kg, IM] / ketamine [20 mg/kg, IM]). The radiographs were taken and evaluated by the same investigator to prevent interobserver variation. Because of the radiographic positioning difficulty, unanesthetized radiographic imaging revealed higher repetition number than the anesthetized; therefore, radiation safety decreased. The administration of diazepam/ketamine and medetomidine/ketamine was sufficient in terms of both muscle relaxation and duration of the anesthesia; however, some dogs under propofol anesthesia were required maintenance doses to complete radiographic imaging procedure. Unanesthetized radiographic images of the dogs had significantly lower (P < .001) hip score, distraction index (DI), subluxation index (SI), and higher compression index (CI) (P< .001), when compared with anesthetized radiographic images. When compared the anesthetic protocols, propofol revealed lower (P< 0.001) hip score, DI, SI, and higher (P < .001) CI than medetomidine/ketamine. Medetomidine/ketamine is the most appropriate anesthetic protocol for detailed radiographic evaluation of CHD considering both muscle relaxation and duration of action.

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.

Protein biomarkers in serum and urine for determining presence or absence of hip dysplasia in a canine model.

This study compares serum and urine concentrations of relevant protein biomarkers among adult dogs with or without radiographic canine hip dysplasia (CHD). Adult (≥2 years of age), client-owned dogs (n = 74) radiographically categorized as having at least "good" hips (n = 49) or having "mild," "moderate," or "severe" hip dysplasia (n = 25) by the Orthopedic Foundation for Animals (OFA). Urine and serum samples were obtained from each dog at a single time-point and processed and analyzed for relevant protein biomarkers. Urinary concentrations of CTX-II (p < 0.001) and TIMP-1 (p = 0.002) were significantly lower in dogs with CHD compared to dogs with no CHD. ROC curve analyses were successful in establishing a panel of four biomarkers (urinary CTX-I and II, serum MMP-9, and serum PIICP) with high discriminatory capability for the presence or absence of hip dysplasia in adult dogs (AUC = 0.89). Urine and serum biomarkers can distinguish adult dogs with radiographic CHD from those with no CHD with a sensitivity of 0.95 and specificity of 0.77 using ROC analysis with AUC 0.89. Clinical Significance: This finding suggests that this simple, minimally invasive diagnostic technique has potential for discriminating dysplastic dogs from dogs with normal hips, with possible translational application to humans based on similar etiopathogenesis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-5, 2019.

Technical Repeatability and Reproducibility of the Stress Radiographs Performed with the Vezzoni-Modified Badertscher Hip Distension Device.

OBJECTIVE: The aim of this study was to evaluate the repeatability and reproducibility of the radiographical stress technique using the Vezzoni-modified Badertscher distension device (VMBDD). MATERIALS AND METHODS: Stress radiographs of 10 dogs obtained with the VMBDD were performed consecutively by two different operators and then measured twice by a third veterinarian. The technical repeatability was first assessed individually for the two operators who took the stress radiographs, followed by the technical reproducibility. The obtained variances were used to calculate the 95% limits of agreement for the measurement repeatability, the technical repeatability and the technical reproducibility. RESULTS: Both the technical repeatability and reproducibility of the VMBDD technique were good, with the 95% limits of agreement of the measurement repeatability and technical repeatability equalling ± 0.07 overall, and the 95% limits of agreement of the technical reproducibility being ± 0.09. CLINICAL SIGNIFICANCE: These results, in combination with the previous results for the measurement of the laxity index, support the use of the VMBDD as a reliable in-house evaluation method to assess the hip joint by trained clinicians. For screening purposes, however, we suggest to limit the number of evaluators, to limit the variability.