Use of the caudolateral curvilinear osteophyte as an early marker for future development of osteoarthritis associated with hip dysplasia in dogs

Establishment of an ultrasound-guided protocol for the assessment of hip joint osteoarthritis in rabbits-A sonoanatomic study

Ultrasound (US) has emerged as one of the most applied imaging tools to diagnose musculoskeletal disorders and assist in guided intra-articular administrations. Nevertheless, in evaluating the rabbit hip joint, there is a need for an ultrasonographic approach. Therefore, this study aimed to describe the hip sonoanatomy, develop and validate a US-guided protocol to assess the hip joint in rabbits and apply this protocol in vivo. This study was carried out in three phases, phase I: a pilot cadaveric study, to assess the applicability of different US approaches in the hip of rabbits and, consequently, develop a detailed US-guided protocol (2 rabbit cadavers, n = 4 hips); phase II: validation of the established US-guided protocol through a numerical scoring system in healthy joints (11 rabbit cadavers, n = 22 hips), and, lastly, phase III: application of the US-guided protocol in vivo in osteoarthritic joints (5 rabbits, n = 5 hips). A total of six planes were validated, two in the ventral approach and four in the dorsal approach. The ventral transverse plane was deemed more informative regarding the hip joint sonoanatomy, enabling the identification of a greater number of structures when compared to the other planes. Nevertheless, this study suggested that the isolated application of a plane was deemed insufficient for a complete and detailed evaluation of the hip joint anatomy, rendering it necessary to employ other planes complementarily. Furthermore, the established US-guided protocol allowed a definitive diagnosis of OA, and osteophytes and capsular hypertrophy were among the defects most frequently detected. This novel study provided US anatomical landmarks for forthcoming therapeutic research and monitoring of OA development, granting the accurate identification of osseous and cartilaginous defects.

Femoral Neck Thickness Index as an Indicator of Proximal Femur Bone Modeling

The alteration in the shape of the femoral neck is an important radiographic sign for scoring canine hip dysplasia (CHD). Previous studies have reported that the femoral neck thickness (FNT) is greater in dogs with hip joint dysplasia, becoming progressively thicker with disease severity. The main objective of this work was to describe a femoral neck thickness index (FNTi) to quantify FNT and to study its association with the degree of CHD using the Fédération Cynologique Internationale (FCI) scheme. A total of 53 dogs (106 hips) were randomly selected for this study. Two examiners performed FNTi estimation to study intra- and inter-examiner reliability and agreement. The paired t-test, the Bland-Altman plots, and the intraclass correlation coefficient showed excellent agreement and reliability between the measurements of the two examiners and the examiners' sessions. All joints were scored in five categories by an experienced examiner according to FCI criteria. The results from examiner 1 were compared between FCI categories. Hips that were assigned an FCI grade of A (n = 19), B (n = 23), C (n = 24), D (n = 24), and E (n = 16) had a mean ± standard deviation FNTi of 0.809 ± 0.024, 0.835 ± 0.044, 0.868 ± 0.022, 0.903 ± 0.033, and 0.923 ± 0.068, respectively (ANOVA, p < 0.05). Therefore, these results show that FNTi is a parameter capable of evaluating proximal femur bone modeling and that it has the potential to enrich conventional CHD scoring criteria if incorporated into a computer-aided diagnosis capable of detecting CHD.

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).

Prevalence of Primary Radiographic Signs of Hip Dysplasia in Dogs

Hip dysplasia is a disabling orthopedic disease in dogs. The aim of this retrospective study was to evaluate the morphological aspects and radiographic changes in the development of hip dysplasia in adult dogs, and to describe the frequency of each radiographic parameter according to each Fédération Cynologique Internationale (FCI) grade. Brass descriptive forms for the evaluation of hip dysplasia were obtained from the archive of the Italian Fondazione Salute Animale, and the radiographic evaluation of 642 hips were processed. Sixteen radiographic criteria were assessed, divided into six main parameters: acetabulum, femoral head and its position in the acetabulum, femoral neck, joint space, and Norberg angle. The initial mild alterations were shown in the craniolateral acetabular rim (31.8%), slightly divergent in the joint space in 58.6% of FCI-A. The spherical shape of the femoral head was mildly small/flattened in 56.9% of FCI-B, in addition to a slightly cylindrical-shaped femoral neck (60.5%) and slightly lost contours (55.0%). Changes in acetabular depth (45.0%), and in the cranial acetabular margin (56.7%) were found in FCI-C. The center of the femoral head was lateral to the dorsal acetabular rim in 70.0% of FCI-B; the Norberg angle appeared normal in 70.6% of FCI-B. Elaboration of the radiographic criteria from the Brass descriptive forms allowed for the extrapolation of accurate knowledge regarding morphologic changes in the development of dysplasia by providing detailed information for each individual. In particular, the present survey showed that the morphological alterations of the acetabulum prevailed over those of the femoral head only at the beginning of the development of canine hip dysplasia, and then worsened after the changes occurred in the femoral head and neck.

The influence of IL-1 and C-reactive protein levels in synovial fluid of companion dogs with bilateral hip osteoarthritis on various clinical disease parameters

OBJECTIVE

To evaluate IL-1 and C-reactive protein (CRP) levels in the synovial fluid in dogs with bilateral hip osteoarthritis and their relation to animals' clinical, radiographic, and thermographic disease signs.

SAMPLE

100 joints from police working dogs.

PROCEDURES

Synovial fluid, IL-1, and CRP levels, weight distribution, joint range of motion, thigh girth, digital thermography, and radiographic signs of the joints were recorded. Data from 4 clinical metrology instruments (CMIs) were collected. Results were compared by age, sex, and Orthopedic Foundation for Animals hip scores with the independent samples t test, ANOVA, and Pearson correlation coefficient (P < .05).

RESULTS

The sample included 100 pelvic limbs, equally distributed between left and right pelvic limbs 30 males and 20 females, with a mean age of 6.5 ± 2.4 years and body weight of 26.7 ± 5.2 kg. IL-1 levels, particularly above 200 pg/mL, may be related to the development of caudolateral curvilinear osteophyte, which then expresses a toll on the patient's levels of pain and activity. It was unclear if the CRP levels were a consequence of inflammatory activity within the joint or a reflection of a better prognosis. Increasing body weight was related to worse CMI scores.

CLINICAL RELEVANCE

We described the relation of IL-1 and CRP synovial concentration levels with several clinical signs, diagnostic imaging, laboratory findings, and CMI results of animals with osteoarthritis. Further studies are required to determine the interest of each parameter for the prognosis and treatment monitoring.

Effect of a single intra-articular administration of stanozolol in a naturally occurring canine osteoarthritis model: a randomised trial

Osteoarthritis (OA) is a disease with a high negative impact on patient’s quality of life and a high financial burden. It is a source of chronic pain and affects all mammals, including humans and dogs. As the dog is a common model for translation research of human OA, and exploring spontaneous dog OA can improve the health and well-being of both humans and dogs. To describe the effect of the intra-articular administration of stanozolol in a naturally occurring canine OA model, forty canine (N = 40) hip joints were randomly assigned to receive stanozolol or saline (control). On treatment day and at 8, 15, 30, 90, and 180 days post-treatment, several evaluations were conducted: weight distribution, joint range of motion, thigh girth, digital thermography, and radiographic signs. Also, synovial fluid C-reactive protein and interleukin-1 levels were evaluated. Results from four Clinical Metrology Instruments was also gathered. Results were compared with Repeated Measures ANOVA, with a Huynh–Feldt correction, paired-samples t-test, or Wilcoxon signed-rank test, with p < 0.05. OA was graded as mild (90%), moderate (5%), and severe (5%), including both sexes. They had a mean age of 6.5 ± 2.4 years and a bodyweight of 26.7 ± 5.2 kg. No differences were found between groups at treatment day in all considered evaluations. Weight distribution showed significant improvements with stanozolol from 15 days (p < 0.05) up to 180 days (p < 0.01). Lower values during thermographic evaluation in both views taken and improved joint extension at 90 (p = 0.02) and 180 days (p < 0.01) were observed. Pain and function scores improved up to 180 days. In the control group, radiographic signs progressed, in contrast with stanozolol. The use of stanozolol was safe and produced significant improvements in weight-bearing, pain score, and clinical evaluations in a naturally occurring canine OA model.

Evaluation of digital thermography imaging to assess and monitor treatment of police working dogs with naturally occurring hip osteoarthritis

BACKGROUND

In dogs, thermal imaging has been documented only recently, but a growing interest in this modality has led to studies using thermography to assess pathologies in the canine hip, stifle, elbow, intervertebral disc, and bone neoplasia. This study aimed to evaluate the use of digital thermography in assessing and evaluating treatment response in dogs with hip osteoarthritis (OA) and comparing its results with an objective measure and two clinical metrology instruments. In an experimental, randomized, double-blinded study, one hundred hip joints of fifty police working dogs with bilateral hip OA were evaluated. A dorsoventral and lateral thermographic image were obtained on days 0, 8, 15, 30, 90, and 180. Mean and maximal temperatures were determined. Additionally, the animal's weight-bearing distribution and radiographic examination of the hip joint (extended legs ventrodorsal view) were performed. Copies of the Canine Brief Pain Inventory (CBPI) and Canine Orthopaedic Index (COI) were obtained. Results were analyzed by ANOVA, followed by an LSD post-hoc test, and correlations were assessed with Spearman correlation coefficient, with p < 0.05.

RESULTS

Values recorded on the lateral view were higher than those on the dorsoventral view. No differences or correlations were found between Orthopedic Foundation for Animals hip grades and temperature. Digital thermographic images showed a weak significant correlation with weight-bearing evaluations (r = 0.13, p < 0.01) and different clinical metrology instruments scores (r = - 0.25, p < 0.01 for pain severity score, and r = - 0.21, p = 0.04 for gait). It also correlated with radiographic findings, specifically the circumferential femoral head osteophyte and caudolateral curvilinear osteophyte.

CONCLUSION

To our knowledge, this is the first study presenting the digital thermography assessment of Police working dogs submitted to treatment for hip OA. Digital thermography, mainly based on a lateral view evaluation, showed a weak significant correlation with stance analysis and clinical metrology instruments scores.

Comparison of clinical and radiographic signs of hip osteoarthritis in contralateral hip joints of fifty working dogs

OBJECTIVE

This study aimed to compare the symmetry of clinical and radiographic signs of right and left pelvic limbs of dogs with bilateral hip osteoarthritis (OA) and evaluate the association of physical findings and radiographic abnormalities.

PATIENTS AND METHODS

One hundred pelvic limbs of police working dogs with bilateral hip OA were evaluated, following a screening program. Weight distribution, joint range of motion at flexion and extension, thigh girth, and radiographic signs were recorded and compared with the results of the contralateral limb and by breed, age, and sex with the Paired Samples T-Test and Pearson correlation coefficient, with p<0.05.

RESULTS

The sample mean age was 6.5±2.2 years, and the bodyweight of 26.7±5.3kg. No significant differences were observed when comparing weight distribution, joint range of motion, and thigh girth of left and right limbs. Weight distribution and age showed a statistically significant correlation with joint extension. The right limbs showed a significantly higher frequency of circumferential femoral head osteophyte (CFHO) regarding radiographic signs. Limbs with CFHO or caudolateral curvilinear osteophyte had significantly larger joint flexion angle (p = 0.02) and smaller extension angle (p<0.01), respectively, compared to those that did not. Age showed a significant correlation with the presence of several radiographic findings, as did different breeds.

CONCLUSION

Clinical and radiographic signs occur symmetrically in naturally occurring hip OA in police working dogs. Several correlations were observed between the evaluations performed and differences between breeds, which can be useful in assessing and early diagnosis of hip OA.

Management of Osteoarthritis Using 1 Intra-articular Platelet Concentrate Administration in a Canine Osteoarthritis Model

BACKGROUND

Osteoarthritis (OA) represents a significant burden to societies, as it affects quality of life and performance and implies a large cost in terms of health care. Autologous platelets are a regenerative treatment modality for OA that are thought to be a potential stimulation of the natural healing cascade.

PURPOSE

To describe the effect of the platelet concentrate V-PET in the management of OA in a naturally occurring canine model, using several outcome assessment modalities.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 40 joints of active working police dogs with hip OA were randomly assigned to a control group (CG) and a platelet concentrate group (PCG; treatment) and evaluated. At treatment day (T0) and 8, 15, 30, 90, and 180 days after treatment, weight distribution, joint range of motion at flexion and extension, thigh girth, digital thermography, radiographic signs, 4 clinical metrology instruments, and synovial fluid interleukin 1 and C-reactive protein levels were recorded. Results were compared using repeated-measures analysis of variance with a Huynh-Feldt correction, paired-samples t test, or Wilcoxon signed rank test, with P < .05.

RESULTS

Dogs were 6.5 ± 2.4 years old (mean ± SD) and had a body weight of 26.7 ± 5.2 kg. At T0, 32 (80%) joints were graded as having mild OA, 6 (15%) as moderate, and 2 (5%) as severe. No differences were found between groups at T0. Between the PCG and CG, the symmetry index showed significant improvements in the PCG from 8 days (P = .01) to 180 days (P = .01). Joint flexion also improved in the PCG up to 90 days (P < .05) and extension improved up to 180 days (P < .01). Several clinical metrology instrument scores also improved up to 90 to 180 days after treatment. In the CG, radiographic signs progressed, while the PCG showed some improved signs. In both groups, increasing body weight and age corresponded with worse clinical and laboratory findings.

CONCLUSION

A single injection of platelet concentrate had a positive effect, lasting up to 6 months, on several clinical, imaging, and laboratory signs in a naturally occurring canine OA model.

CLINICAL RELEVANCE

We characterized the effects of this platelet concentrate in dogs, considered the gold standard of the study of OA, with a group of working animals with similar high demands as athletes.

The intra-articular administration of triamcinolone hexacetonide in the treatment of osteoarthritis. Its effects in a naturally occurring canine osteoarthritis model

OBJECTIVE

To evaluate the effect of an intra-articular (IA) administration of triamcinolone hexacetonide, compared with saline.

PATIENTS AND METHODS

Forty (N = 40) hip joints were randomly assigned to a treatment group (THG, n = 20, receiving IA triamcinolone hexacetonide) and a control group (CG, n = 20, receiving IA saline). On treatment day (T0), and at 8, 15, 30, 90 and 180 days post-treatment, weight distribution, joint range of motion, thigh girth, digital thermography, radiographic signs, synovial fluid interleukin-1 and C-reactive protein levels were evaluated. Data from four Clinical Metrology Instruments was also gathered. Results were compared Repeated Measures ANOVA, with a Huynh-Feldt correction, Paired Samples T-Test or Wilcoxon Signed Ranks Test. A Kaplan-Meier test was performed to compare both groups, with p<0.05.

RESULTS

Joints were graded as mild (65%), moderate (20%) and severe (15%). Patients of both sexes, with a mean age of 6.5±2.4 years and bodyweight of 26.7±5.2kg, were included. No differences were found between groups at T0. Comparing THG to CG, weight distribution showed significant improvements in THG from 8 (p = 0.05) up to 90 days (p = 0.01). THG showed lower values during thermographic evaluation in the Lt view (p<0.01). Pain and function scores also improved from 30 to 180 days. Increasing body weight, age, and presence of caudolateral curvilinear osteophyte corresponded to worse response to treatment. Results of the Kaplan Meier test showed significant differences between groups, with THG performing better considering several evaluations and scores.

CONCLUSION

THG recorded significant improvements in weight-bearing and in with the considered CMIs, particularly pain scores. Lower thermographic values were registered in THG up to the last evaluation day. Age, sex, and radiographic findings did significantly influenced response to treatment.

Clinical and diagnostic imaging findings in police working dogs referred for hip osteoarthritis

Background

Osteoarthritis (OA) is the most commonly diagnosed joint disease in veterinary medicine, with at least 80% of the cases of lameness and joint diseases in companion animals being classified as OA. Sporting and working animals are more predisposed to develop OA since they are exposed to chronic fatigue injuries, leading to bone and muscular tissue damage and failure, resulting in clinical signs. To characterize the clinical signs and diagnostic findings of Police working dogs presenting with bilateral hip OA at the time of diagnosis. Fifty animals were evaluated with a bodyweight ≥ 15 kg, be older than two years, and without any medication or nutritional supplements for ≥ 6 weeks.

Results

Weight distribution, joint range of motion at flexion and extension, thigh girth, digital thermography, and radiographic signs were collected. Data from different Clinical Metrology Instruments (CMI) were collected: Canine Brief Pain Inventory, Liverpool Osteoarthritis in Dogs, Canine Orthopedic Index, and the Hudson Visual Analogue Scale. Results were compared by breed, age, sex, and Orthopaedic Foundation for Animals hip grades with the Independent Samples T-Test, ANOVA followed by a Bonferroni post hoc test, and Pearson correlation coefficient, with p < 0.05. The sample included 30 males and 20 females, with a mean age of 6.5 ± 2.4 years and a bodyweight of 26.7 ± 5.2 kg. Animals with weight distribution below normal levels had significant variations of joint extension and function scores. This evaluation was the only not correlated with at least one breed. Animals with caudolateral curvilinear osteophyte showed a poorer clinical presentation and worse scores in all considered CMIs. Radiographic changes correlated with age and corresponded to worse CMIs scores and weight distribution. Dutch Shepherd Dogs showed better CMI scores than the other considered breeds.

Conclusions

Police working dogs presented with complaints related to hip OA at an early stage of the disease. Hip scores influenced clinical presentation, with moderate cases showing lower thigh girth and worse pain interference and severity, and function scores than mild cases. Patients with severe OA had lower thermographic evaluations than patients with moderate OA. Age was the primary variable influencing considered CMI scores.

Risk Factors for Canine Osteoarthritis and Its Predisposing Arthropathies: A Systematic Review

Osteoarthritis is a common clinical and pathological end-point from a range of joint disorders, that ultimately lead to structural and functional decline of the joint with associated lameness and pain. Increasing understanding of the risk factors associated with osteoarthritis will assist in addressing the significant threat it poses to the welfare of the dog population and implementing preventive measures. Presented here, is the first comprehensive systematic review and evaluation of the literature reporting risk factors for canine osteoarthritis. This paper aimed to systematically collate, review and critically evaluate the published literature on risk factors for canine osteoarthritis and its predisposing conditions such as developmental joint dysplasias, cruciate ligament degeneration, and patellar luxation. Peer-reviewed publications were systematically searched for both osteoarthritis and predisposing arthropathies on Web of Science and PubMed following PRISMA (2009) guidelines, using pre-specified combinations of keywords. Sixty-two papers met the inclusion criteria and were evaluated and graded on reporting quality. Identified risk factors included both modifiable factors (neuter status and body weight) for which intervention can potentially affect the risk of occurrence of osteoarthritis, and unmodifiable factors (sex, breed, and age) which can be used to identify individuals most “at risk.” Osteoarthritis in dogs frequently develops from predisposing arthropathies, and therefore risk factors for these are also important to consider. Papers evaluated in this study were rated as medium to high-quality; gap analysis of the literature suggests there would be significant benefit from additional research into the interactions between and relative weighting of risk factors. There are a number of examples where research outcomes are conflicting such as age and sex; and further investigation into these factors would be beneficial to attain greater understanding of the nature of these risks. Comprehensively collating the published risk factors for osteoarthritis and its predisposing conditions offers opportunities to identify possible means for control and reduction within the population through preventative methods and control strategies. These factors are highlighted here, as well as current literature gaps where further research is warranted, to aid future research direction.

Features of the Femoral Proximocaudal Joint Capsule Insertion Among Canids

This observational study was conducted to evaluate the anatomic relationship between the proximocaudal femoral joint capsule insertion and the femoral caudolateral curvilinear osteophyte (CCO), across ancient and modern domestic and non-domestic canids. Museum specimens of proximal femora were screened for presence of remnant enthesophytes of the caudal joint capsule insertion (first inclusion criterion) and then for the CCO (second inclusion criterion). The initially screened population included 267 dry bone specimens: Six Canis species, hybrid coyote × domestic dog, and five vulpines (three Vulpes species, one Urocyon, and one Nyctereutes). Proximocaudal joint capsule insertion remnant enthesophytes were limiting at n = 19 specimens: Seven ancient domestic dogs, four modern coyotes, two ancient coyotes, two modern hybrid coyote × dog, two modern red foxes, and two modern raccoon dogs. The joint capsule enthesophytes are associated with inflammation, but are observed far less frequently than the CCO. The CCO is seen radiographically but is visible more frequently by direct inspection. The primary inclusion criterion necessarily was a visible caudal joint capsule insertion; spatial relationships of the CCO can be assigned with confidence only when a capsule insertion line can be recognized clearly. We demonstrate that the anatomic CCO associates with the joint capsule insertion being nonspecific and species-independent. A joint capsule insertion-CCO spatial relationship across species is an important new observation, strongly indicating that both are pathological features. Our data indicate need for new research to characterize the canid coxofemoral joint and its overt and incipient pathology in a phylogenetic context. Anat Rec, 302:2164-2170, 2019. © 2019 American Association for Anatomy.

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.

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.

Morgan line and its relationship with distraction index, angle of inclination and degenerative joint disease in the diagnosis of canine hip dysplasia

ABSTRACT We evaluated 160 hip joint radiographs of 40 dogs of different large breeds (25 females and 15 males) from the metropolitan area of Belo Horizonte, Minas Gerais, Brazil. The radiographs of each dog were obtained at two different stages: stage 1 (mean 7.23 months) and stage 2 (mean 14.25). The conventional radiographic method (CRM) and the radiographic distraction method (RDM) were used, carried out in both stages. CRM measured the Norberg angle (NA), the angle of inclination (AI) and evaluated the presence of degenerative joint disease (DJD). The MRD was performed to establish the distraction index (DI). The aims were to evaluate the presence of the Morgan line and other signs of DJD and correlate them with the degree of canine hip dysplasia (CHD) and also check if the DI greater than 0.3 (first stage) was associated with the presence of ML (second stage). It was found that DI, AI and changes of femoral neck and the formation of osteophytes were associated with the presence of ML. It was observed that if the DI is greater than 0.3 at the first stage, the chance of a positive outcome of ML in the second stage increases by 7.2 times. Thus, 49 joints showed DI > 0.3 at the first stage, in which 31 (63.3 %) presented ML at the second stage. Of the 31 animals that showed DI ≤ 0.3 at first, six (19.4%) had LM at the second stage. There has been a significant association between the presence of ML and the degree of CHD. The more severe the CHD, the higher the percentage of positive ML results. Thus, among the 24 (60 %) animals that showed ML, 11 (45.83 %) were classified as severe dysplastics, 5 (20.83%) as moderate and 8 (33.33 %) as mild. None of the animals classified as normal or borderline presented ML. Among the 8 animals classified as mild dysplastics, 5 showed only ML as DJD.

The Anthropoid Crista Trochanterica and the Hip Joint Capsule

The tubercle on the posterior aspect of the femoral neck (the crista trochanterica) has been repeatedly remarked upon because of its presence in early fossil apes, yet the function of this tubercle has eluded researchers. The prevailing explanation for the tubercle is that it relates to a strong ischiofemoral ligament, although none of the hypotheses for this bony projection have been systematically evaluated. This study surveyed 41 extant anthropoid species (n = 267 individuals) for the presence of a crista trochanterica. The soft tissue structures of the hip joint were then dissected and described for a sample of anthropoid cadavers (n = 14) in order to evaluate different hypotheses related to function of this tubercle. This study confirmed that the crista trochanterica is found in most cercopithecoids and platyrrhines, and is not present in great apes. The tubercle is rarely present in hylobatids, contrary to prior reports. The ischiofemoral ligament is not usually well-developed in anthropoids and does not fully explain the crista trochanterica morphology, although all cadavers displayed a well-developed zona orbicularis running along the posterior aspect of the joint capsule. The hip joint capsule itself inserted along the crista trochanterica in some individuals, typically those with an elongate crista trochanterica, but was highly variable in regards to the position of the tubercle. The hypotheses for the crista trochanterica are considered within the context of these findings, although the exact function of the tubercle remains unresolved.

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.

What can cohort studies in the dog tell us?

This paper addresses the use of cohort studies in canine medicine to date and highlights the benefits of wider use of such studies in the future. Uniquely amongst observational studies, cohort studies offer the investigator an opportunity to assess the temporal relationship between hypothesised risk factors and diseases. In human medicine cohort studies were initially used to investigate specific exposures but there has been a movement in recent years to more broadly assess the impact of complex lifestyles on morbidity and mortality. Such studies do not focus on narrow prior hypotheses but rather generate new theories about the impact of environmental and genetic risk factors on disease. Unfortunately cohort studies are expensive both in terms of initial investment and on-going costs. There is inevitably a delay between set up and the reporting of meaningful results. Expense and time constraints are likely why this study design has been used sparingly in the field of canine health studies. Despite their rather limited numbers, canine cohort studies have made a valuable contribution to the understanding of dog health, in areas such as the dynamics of infectious disease. Individual exposures such as neutering and dietary restriction have also been directly investigated. More recently, following the trend in human health, large cohort studies have been set up to assess the wider impact of dog lifestyle on their health. Such studies have the potential to develop and test hypotheses and stimulate new theories regarding the maintenance of life-long health in canine populations.

Radiographic hip joint phenotype of the Pembroke Welsh Corgi

OBJECTIVE

To investigate the radiographic hip joint phenotype of the Pembroke Welsh Corgi.

STUDY DESIGN

Prospective and retrospective cross-sectional study.

ANIMALS

Pembroke Welsh Corgis (n = 399).

METHODS

Ventrodorsal, hip-extended radiographs were evaluated for subluxation, osteoarthritis (OA), caudolateral curvilinear osteophytes (CCO), and circumferential femoral head osteophytes (CFHO) of PennHIP evaluated Corgis. Joint laxity was measured by distraction index (DI).

RESULTS

All Corgis had DI > 0.30 (mean, 0.66), 6.8% had OA, 18% had subluxation, 22.3% had CCO, and 74.4% had CFHO. Higher DI increased the odds for subluxation and canine hip dysplasia (CHD) but not for OA, CCO, or CFHO. The presence of CCO increased the odds for OA by 4.6 times (P = .002) and 2.2 times (P = .01) for hip dysplasia. All dogs with OA had CFHO. The presence of CFHO increased the odds for subluxation by 8.7 times (p < .001) and 8.9 times (P < .001) for hip dysplasia. Subluxation increased the odds for OA by 15.4 times (P < .001).

CONCLUSION

Corgis had a low frequency of conventional OA despite having hip laxity that has been shown to correlate with hip OA and hip dysplasia in large-breed dogs. The relationship between CCO and OA was similar to published findings in nonchondrodystrophic large-breed dogs and the CFHO was significantly associated with subluxation. Both CCO and CFHO are associated with hip dysplasia in this small chondrodystrophic breed.

Invited review: study design considerations for clinical research in veterinary radiology and radiation oncology

High quality clinical research is essential for advancing knowledge in the areas of veterinary radiology and radiation oncology. Types of clinical research studies may include experimental studies, method-comparison studies, and patient-based studies. Experimental studies explore issues relative to pathophysiology, patient safety, and treatment efficacy. Method-comparison studies evaluate agreement between techniques or between observers. Patient-based studies investigate naturally acquired disease and focus on questions asked in clinical practice that relate to individuals or populations (e.g., risk, accuracy, or prognosis). Careful preplanning and study design are essential in order to achieve valid results. A key point to planning studies is ensuring that the design is tailored to the study objectives. Good design includes a comprehensive literature review, asking suitable questions, selecting the proper sample population, collecting the appropriate data, performing the correct statistical analyses, and drawing conclusions supported by the available evidence. Most study designs are classified by whether they are experimental or observational, longitudinal or cross-sectional, and prospective or retrospective. Additional features (e.g., controlled, randomized, or blinded) may be described that address bias. Two related challenging aspects of study design are defining an important research question and selecting an appropriate sample population. The sample population should represent the target population as much as possible. Furthermore, when comparing groups, it is important that the groups are as alike to each other as possible except for the variables of interest. Medical images are well suited for clinical research because imaging signs are categorical or numerical variables that might be predictors or outcomes of diseases or treatments.

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.

A longitudinal study of the influence of lifetime food restriction on development of osteoarthritis in the canine elbow

OBJECTIVE

To report the effects of age and lifetime calorie restriction on development and progression of osteoarthritis (OA) in elbow joints of Labrador retrievers.

STUDY DESIGN

Longitudinal cohort study.

ANIMALS

Labrador retriever dogs (n=48).

METHODS

Puppies from 7 litters were allotted to 2 groups of 24 dogs each. Diet-restricted (DR) dogs received 25% fewer calories than control-fed (CF) pair mates. Elbow radiographs were taken at 6 and 8 years of age and end of life (EOL). Gross and histopathologic evaluations for OA occurred at EOL.

RESULTS

There was no statistical difference in radiographic OA frequency between groups at any of the time points. Radiographic OA severity was greater for CF dogs at 6 years only (P<.05). There was no significant difference between feeding groups for histopathologic prevalence or severity of OA. Similarly, there were no differences in gross OA lesions between the groups (P>.05). Fragmented medial coronoid process, un-united anconeal process, and osteochondrosis were not present in any elbow.

CONCLUSION

No differences in prevalence or severity of radiographic and histopathologic elbow OA were found between feeding groups. Diet restriction resulted in a 1.8-year extension in median lifespan but no additional incremental worsening of elbow disease. Evaluation at time points <6 years may have revealed larger differences in OA prevalence and severity between the dietary groups.

CLINICAL RELEVANCE

These findings support calorie restriction as a clinical tool to slow progression of elbow OA.

Puppy line, metaphyseal sclerosis, and caudolateral curvilinear and circumferential femoral head osteophytes in early detection of canine hip dysplasia

Ventrodorsal extended hip radiographs were analyzed from Foxhounds, Irish setters, Greyhounds, and Labrador retrievers radiographed four to seven times between 8 and 110 weeks of age. Occurrence in these 91 dogs of a puppy line, an ill-defined zone of proximal femoral metaphyseal sclerosis, a femoral neck linear sclerosis, or circumferential linear femoral head osteophytosis at 15-17 weeks of age were compared with hip joint laxity, as measured by distraction index, and to later findings of caudal curvilinear femoral neck osteophytes, circumferential femoral head osteophytes, hip incongruity consistent with hip dysplasia and degenerative joint disease by 52 weeks of age. A puppy line and/or femoral metaphyseal sclerosis was common at 15-17 weeks of age for dogs at mimimal risk (Greyhounds) and high risk (Foxhounds) of developing early degenerative joint disease associated with canine hip dysplasia. Though 44% of Greyhound hips had puppy lines and 28% had femoral metaphyseal sclerosis at 15-17 weeks of age, no Greyhound had a caudolateral curvilinear osteophyte or circumferential femoral head osteophyte at 24-27 or 52 weeks of age. No significant relationship was found between occurrence of a puppy line, a circumferential femoral head osteophyte or femoral metaphyseal sclerosis at 15-17 weeks and canine hip dysplasia or degenerative joint disease incidence at 42-52 weeks. Presence of a caudolateral curvilinear osteophyte in at least one hip at 24-27 weeks was significantly related to the diagnosis of canine hip dysplasia by 42-52 weeks. When both a caudolateral curvilinear osteophyte and a circumferential femoral head osteophyte were present in a hip at 24-27 weeks, degenerative joint disease was evident in all such hips by 42-52 weeks of age.

Relationships among measurements obtained by use of computed tomography and radiography and scores of cartilage microdamage in hip joints with moderate to severe joint laxity of adult dogs

OBJECTIVE

To evaluate correlations among measurements on radiographic and computed tomography (CT) images with articular cartilage microdamage in lax hip joints of dogs.

ANIMALS

12 adult mixed-breed hounds.

PROCEDURES

Pelvic CT and radiography were performed. Hip joints were harvested following euthanasia. Orthopedic Foundation for Animals (OFA) and PennHIP radiograph reports were obtained. Norberg angle (NA) and radiographic percentage femoral head coverage (RPC) were determined. Center-edge angle (CEA), horizontal toit externe angle (HTEA), ventral acetabular sector angle (VASA), dorsal acetabular sector angle (DASA), horizontal acetabular sector angle (HASA), acetabular index (AI), and CT percentage femoral head coverage (CPC) were measured on 2-dimensional CT images. Femoral head-acetabular shelf percentage was measured on sagittal 3-dimensional CT (SCT) and transverse 3-dimensional CT (TCT) images. Light microscopy was used to score joint cartilage. Relationships of OFA confirmation and PennHIP osteoarthritis scores with radiography, CT, and cartilage variables and relationships of cartilage scores with radiography and CT measurements were evaluated with Spearman rank correlations. Pearson correlation was used for relationships of distraction index (DI) with radiography, CT, and cartilage variables.

RESULTS

Significant relationships included PennHIP osteoarthritis score with cartilage score, CEA, HTEA, DASA, AI, CPC, and TCT; OFA confirmation score with cartilage score, NA, RPC, CEA, HTEA, DASA, AI, CPC, and TCT; cartilage score with NA, RPC, CEA, HTEA, DASA, HASA, AI, and TCT; and DI with cartilage score, CEA, HTEA, DASA, HASA, AI, and CPC.

CONCLUSIONS AND CLINICAL RELEVANCE

CT appeared to be a valuable imaging modality for predicting cartilage microdamage in canine hip joints.

Evaluation of a circumferential femoral head osteophyte as an early indicator of osteoarthritis characteristic of canine hip dysplasia in dogs

OBJECTIVE

To determine the relationship between a circumferential femoral head osteophyte (CFHO) and osteoarthritis characteristic of canine hip dysplasia, and to ascertain whether CFHO, like osteoarthritis, varies between diet-restricted and control-fed dogs.

DESIGN

Longitudinal cohort study.

ANIMALS

48 Labrador Retrievers.

PROCEDURES

Dogs were paired by size, sex, and litter and assigned to 1 of 2 equal groups at 2 months of age. The control-fed group was fed ad libitum, and the diet-restricted group was fed 25% less on a pairwise basis of the same diet for life. The dogs' hip joints were radiographed yearly for life. Each radiograph was evaluated for radiographic signs of osteoarthritis characteristic of hip dysplasia and for the presence and severity of a CFHO.

RESULTS

41 of the 48 (85.4%) dogs had a CFHO, which was detected at a median age of 5.4 years, and 33 of those 41 (80.5%) developed radiographic evidence of osteoarthritis. Nineteen (79.2%) dogs in the diet-restricted group and 22 (91.7%) in the control-fed group had a CFHO at a median age of 9 and 3 years, respectively. Of the dogs with a CFHO, 12 (63.2%) in the diet-restricted group and 20 (90.0%) in the control-fed group developed radiographic evidence of osteoarthritis characteristic of hip dysplasia at a median age of 11 and 6.5 years, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated a relationship between the CFHO and subsequent development of radiographic signs of osteoarthritis. If a CFHO is present in Labrador Retrievers, it might be considered an early indicator of osteoarthritis.

Interobserver agreement in the diagnosis of canine hip dysplasia using the standard ventrodorsal hip-extended radiographic method

OBJECTIVES

To determine the agreement between observers and to investigate the effect of observer experience in diagnosing canine hip dysplasia and providing final scoring of hips using the standard ventrodorsal hip-extended radiographic method. The agreement of the final scoring, with a presumed correct assessment based on the Norberg angle, is also investigated.

METHODS

Thirty observers were requested to read 50 ventrodorsal hip-extended radiographs of 25 dogs according to Federation Cynologique International criteria. Groups of experienced (nine members) and inexperienced (21 members) observers were used.

RESULTS

For providing the distinction between dysplastic versus non-dysplastic dogs, the average interobserver agreement was 72 per cent and was significantly higher (P<0.0001) than the score that could be expected by chance without any agreement between observers. For providing the final score (A, B, C, D or E), an average interobserver agreement of 43.6 per cent was found. In the experienced group, an agreement score of 76 per cent was found for the distinction between AB versus non-AB and an agreement score of 81 per cent was found for the distinction between C versus non-C. The agreement score was significantly higher (P<0.0001) for the experienced group than for the inexperienced group in all cases. Agreement between the presumed correct assessment based on the Norberg angle and the observer's evaluation was low (P=0.35), irrespective of whether the observers were experienced (71.8 per cent correct assessments) or inexperienced (69 per cent correct assessments).

CLINICAL SIGNIFICANCE

Although interobserver agreement is low, observer experience increases agreement.

Lifelong diet restriction and radiographic evidence of osteoarthritis of the hip joint in dogs

OBJECTIVE

To evaluate the effects of diet restriction on development of radiographic evidence of hip joint osteoarthritis in dogs.

DESIGN

Longitudinal cohort study.

ANIMALS

48 Labrador Retrievers from 7 litters.

PROCEDURES

Forty-eight 6-week-old puppies from 7 litters were paired with littermates by sex and weight, and each pairmate was randomly assigned to 1 of 2 groups of 24 dogs each. Starting at 8 weeks of age, 1 group was fed ad libitum (control fed) and the other was fed 25% less (restricted fed) of the same diet for life on a pairwise basis. The dogs' hip joints were radiographed in the standard ventrodorsal hip-extended view at multiple intervals prior to 1 year of age and at annual intervals thereafter on the basis of birth anniversary. A board-certified radiologist unaware of group assignment scored the radiographs for evidence of osteoarthritis.

RESULTS

Prevalence of radiographic evidence of hip joint osteoarthritis in all dogs increased linearly throughout the study, from an overall prevalence of 15% at 2 years to 67% by 14 years. Restricted-fed dogs had lower prevalence and later onset of hip joint osteoarthritis. Median age at first identification of radiographic evidence of hip joint osteoarthritis was significantly lower in the control-fed group (6 years), compared with the restricted-fed group (12 years).

CONCLUSIONS AND CLINICAL RELEVANCE

Restricted feeding delayed or prevented development of radiographic signs of hip joint osteoarthritis in this cohort of Labrador Retrievers. Lifetime maintenance of 25% diet restriction delayed onset and reduced severity of hip joint osteoarthritis, thus favorably affecting both duration and quality of life. In addition, the data indicated that development of hip joint osteoarthritis was not bimodal in these dogs but occurred as a continuum throughout life.

Evaluation of gait kinetics in puppies with coxofemoral joint laxity

OBJECTIVE

To characterize ground reaction forces (GRFs) and determine whether there were correlations between forces and passive coxofemoral joint laxity in puppies.

ANIMALS

Fifty-one 16-week-old hound-breed dogs.

PROCEDURE

Force-plate gait evaluation and distraction radiographic imaging were performed. Ground reaction forces evaluated included x (mediolateral), y (craniocaudal breaking and propulsion), and z (vertical) peak force and impulse. Z-plane limb loading and unloading rates, loading interval, and weight distribution and y-plane stance time breaking and propulsion percentages were calculated. One-way ANOVA with the Duncan multiple range test was used to evaluate differences in gait variables among limbs. The relationships of left, right, highest, and mean distraction index (DI) with individual limb data of each dog were evaluated with the Spearman rank correlation. Left and right DIs were compared by means of linear regression analysis.

RESULTS

Mean +/- SEM DI was 0.67 +/- 0.02. Left and right DIs were strongly correlated, but there were no significant relationships between DIs and gait variables. Most fore- and hind limb gait variables differed significantly, whereas paired fore- and hind limb gait variables did not. Asymmetry was most pronounced in the x- and y-planes.

CONCLUSIONS AND CLINICAL RELEVANCE

GRFs were consistent with those of clinically normal mature dogs, supporting an absence of association between GRF and DI in young dogs. The GRFs and elucidation of the relationship between GRFs and DI may be useful for future studies in immature dogs.

Associations between canine juvenile weight gain and coxofemoral joint laxity at 16 weeks of age

OBJECTIVE

Evaluation of the relationship between canine weight gain from 6 to 15 weeks of age and passive coxofemoral joint (CFJ) laxity at 16 weeks of age.

STUDY DESIGN

Longitudinal cohort study.

ANIMALS

Full- or half-sibling hounds (n = 56).

METHODS

Hounds were weighed weekly from 6 to 15 weeks of age. Individual average daily gain (ADG) was calculated for each week (weekly) and for the study (overall). PennHIP distraction index (DI) was determined for each CFJ at 16 weeks. Mixed effects linear models were evaluated for associations of DI (highest and mean) with 15-week weight and ADGs (actual or normalized). Left and right DIs were compared with a Student's paired t-test. Significance was set at P<.05. Trends were considered at P<.10.

RESULTS

Mean (+/-SD) 16-week DI score and 15-week weight was 0.67 +/- 0.16 and 12.5 +/- 1.8 kg, respectively. Within animal left and right DIs were not significantly different. There were no significant associations between DI and any of the weight gains evaluated. There was a trend for a negative relationship between normalized 14-week ADG and DI in one statistical model.

CONCLUSIONS

Weight gain from 6 to 15 weeks of age was unrelated to 16-week PennHIP DI in a homogenous canine population with moderate-to-severe CFJ joint laxity.

CLINICAL RELEVANCE

Based on our results, ad libitum feeding between 6 and 15 weeks of age does not appear to have an adverse impact on joint laxity at 16 weeks of age as measured by the PennHIP DI.

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

OBJECTIVE

To estimate prevalence of canine hip dysplasia (CHD) in Golden Retrievers and Rottweilers and identify sources of bias in published reports.

DESIGN

Prospective study.

ANIMALS

200 clinically normal Golden Retrievers and 140 clinically normal Rottweilers between 24 and 60 months of age referred for hip evaluation (group 1) and 93 clinically normal dogs evaluated for Orthopedic Foundation for Animals (OFA) hip certification (group 2).

PROCEDURE

Hip-extended pelvic radiographs from group 1 dogs were screened for CHD. Radiographs were evaluated twice; the first interpretation used an OFA-type subjective 7-point scoring system, and the second included the caudolateral curvilinear osteophyte as an additional sign of degenerative joint disease. The OFA submission rate of group 2 dogs was determined from the number of official reports returned from the OFA.

RESULTS

Prevalence of CHD in Golden Retrievers ranged from 53% to 73% and in Rottweilers ranged from 41% to 69%. Among dogs referred for OFA evaluation, radiographs from 49 (53%) were submitted to OFA. Of submitted radiographs, 45 (92%) were normal; of radiographs not submitted, 22 (50%) were normal. Radiographs with normal-appearing hips were 8.2 times as likely to be submitted to the OFA. Compared with Golden Retrievers, Rottweiler radiographs were significantly more likely to be submitted for OFA certification.

CONCLUSIONS AND CLINICAL RELEVANCE

Prevalence of CHD in these 2 breeds may be much higher than previously reported in the United States. Results suggest substantial bias in the OFA database, which causes lower estimates of prevalence of CHD.