Norberg Angle Research Articles

Radiographic Measurements of the Hip Joint in Capuchin Monkeys (Sapajus spp.).

Radiographs are useful for the initial evaluation of the hip joints. The information can be utilized for the betterment of animal health or other goals such as anatomic studies and gait analysis, among others. Therefore, this study aimed to evaluate radiographic measurements of the hip joint in capuchin monkeys, kept under human care at a reference center for wildlife. Twelve capuchin monkeys (Sapajus spp.) (three adult males, seven adult females, and two sub-adult females) were evaluated. Ventrodorsal radiographic views were taken under chemical restraint. All measurements on the digital images were performed in triplicate by one examiner. None of the measurements evaluated were statistically different between males and females. No statistical differences were found between hind limbs. The mean (±SD) Norberg angle was 104.92° (±2.82°) and the Wiberg angle was 15.26° (±1.86°). The percentage of the femoral head covered by the acetabulum was 68.57% (±3.65%) and the acetabular index depth to width ratio was 54.66% (±3.85%). In conclusion, the radiographic measurements showed certain morphological features of the hip joint in Sapajus spp. that contribute to improving species knowledge.

Assessment of New Radiographic Traits in Canine Hip Dysplasia (CHD)

Abstract Canine hip dysplasia (CHD) is a polygenic, multifactorial developmental disorder of the hip joint. Hip laxity, an early characteristic of CHD, leads to degeneration within the joint due to mechanical injury. Definitive diagnosis can be achieved by x-ray examination. The aim of our study is to refine CHD assessments using a quantitative planimetry method. The measurement of the Norberg angle (NA) was found subjective and insufficient to measure hip laxity on the standard ventrodorsal projection, because extension of the pelvic limbs stretches the joint capsule and supports joint congruence. Therefore, we have decided to verify other methods of detecting CHD, which include measurement of femoral head coverage (linear and area coverage) and congruence angle (AoC). These parameters could provide us with relevant information about how well the head of the femur fits into the acetabulum and thus might help to assess CHD better, and identify affected individuals better. In our study, we included 122 x-ray images of 3 breeds of dogs of both sexes and at different ages 5.6 ± 1.8 years. The highest correlation was between both femoral head linear and both area overlap for Bavarian hounds. For Bernese mountain dogs it was between right NA and linear and area femoral overlap, between both femoral head linear and both area overlap. For German shepherd dogs it was found between both NA, between right NA and right AoC, between both AoC, between both NA with both femoral overlap and between both AoC and both femoral overlap on the same side.

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±7.1kg. 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.

Goniometric measurements of the femoral joint in dogs with hip dysplasia

Canine hip dysplasia is one of the most common orthopedic dieseases presents in most breeds of dogs but more prevalent in large breeds. Clinical examination through tests such as Ortolani, Barlow, and Bardens, alongside with radiological, tomographic, magnetic resonance, and ultrasonographic examinations, are the only methods for screening and diagnosing canine hip dysplasia. Canine hip dysplasia can lead to other musckuloskeletal diseases, with the most common ones being cruciate ligaments tear and spinal conditions such as IVDD or degenerative myelopathy. To assess hip changes, it is recommended that the patient to be heavily sedated, and the standard exposure will be with the hips in forced extension. Among knee conditions related to hip dysplasia, the most commonly reported are patellar luxation, partial cranial cruciate ligament rupture, and osteoarthritic changes. A study conducted on 65 dogs found concurrent hip dysplasia and patellar luxation in 28% of cases. Clinical goniometry is an objective and non invasive method of measuring joint angles, allowing for the assessment of the normal range of joint movements. This method can indicate the severity of joint pathology. Currently, goniometry is often used in the field of imaging and it can be an important element in assessing the musculoskeletal system. The aim of this paper is to evaluate the effectiveness of goniometric measurements at the knee and hip joint levels in dogs with hip dysplasia and if there is a correlation. A total of 10 dogs from varying breeds of dogs aging from 1 to 3 years old, were deeply sedated in order to measure perform the x-rays in ventro-dorsal hip extended view for measuring the Norberg angle (Na), anatomic Latero-Proximal Femoral Angle (aLPFA), anatomic Latero-Distal Femoral Angle (aLDFA), mechanical Latero-Distal Femoral Angle (mLDFA), mechanical Latero-Proximal Femoral Angle (mLPFA). All patients were part of the clinical cases present in our department and the written consent of the owners was obtained for each dog. Norberg and femoral angles were measured within the local DICOM viewer and the statistical analysis was performed with IBM SPSS Statistics. All images were reviewed by an ECVDI resident, a radiology professor and a radiology intern. All patients within our study had a Na under the reference value of 105º. All the femoral angles were within limits regarding their normal values. We conclude that there is not a signicative relation between the Na and the goniometric values obtained, most likely because of other factors that are influencing these measurements (ex. breed variations, femoral slightly rotation, muscle contracture due to poor anesthesia management, other musculoskeletal genetic disorders etc.). Further research on a more relevant statistical sample is recommended, in order to determine the normal goniometric values and the changes that appear in case of hip dysplasia.

Radiographic findings in the coxofemoral joint of Australian Cattle Dogs

Australian Cattle Dogs (ACD) are medium-sized animals widely used in fieldwork for managing cattle and sheep. There needs to be more information about the conditions these dogs can develop despite being well-characterized animals since the beginning of the 20th century. Hip dysplasia (HD) is a developmental abnormality between the femoral head and the acetabular fossa, which can be debilitating. However, the available literature has no studies on the prevalence of this condition in dogs of this breed. This study aimed to evaluate radiographs of ACD qualitatively and quantitatively. For this purpose, 49 dogs considered healthy without clinical signs of HD were radiographically assessed, and the animals were classified as dysplastic (D) and non-dysplastic (ND). A frequency of 46.9% of dysplastic dogs was observed, with males being more affected. The cortical index (CI) and angle of inclination (AI) could not differentiate D from ND animals; only the Norberg angle (NA) was effective in this differentiation. No correlation was observed between AI, CI, and AN.

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

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. 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. 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. 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.

Femoral parallelism: evaluation and impact of variation on canine hip dysplasia assessment.

Adequate radiographic positioning on the X-ray table is paramount for canine hip dysplasia (HD) screening. The aims of this study were to evaluate femoral parallelism on normal ventrodorsal hip extended (VDHE) view and the effect of femoral angulation (FA) on Norberg Angle (NA) and Hip Congruency Index (HCI). The femoral parallelism was evaluated comparing the alignment of the long femoral axis with the long body axis in normal VDHE views and the effect of FA on NA and HCI on repeated VDHE views with different levels of FA. The femoral long axis in normal VDHE views showed a ranged of FA from -4.85° to 5.85°, mean ± standard deviation (SD) of -0.06 ± 2.41°, 95% CI [-4.88, 4.76°]. In the paired views, the mean ± SD femur adduction of 3.69 ± 1.96° led to a statistically significant decrease NA, and HCI, and femur abduction of 2.89 ± 2.12 led to a statistically significant increase in NA and HCI (p < 0.05). The FA differences were also significantly correlated with both NA differences (r = 0.83) and HCI differences (r = 0.44) (p < 0.001). This work describes a methodology that allows evaluation of femoral parallelism in VDHE views and the results suggest that femur abduction yielded more desirable NA and HCI values and adduction impaired NA and HCI values. The positive linear association of FA with NA and HCI allows the use of regression equations to create corrections, to reduce the influence of poor femoral parallelism in the HD scoring.

Acetabular rim extension using a personalized titanium implant for treatment of hip dysplasia in dogs: short-term results.

Hip dysplasia (HD) is a common orthopedic problem in young dogs. To decrease the laxity of the hip joint related to HD, the surgical treatments are recommended to increase femoral head coverage. ACEtabular rim eXtension (ACE-X) using a personalized 3-dimensional printed titanium shelf implant is a new surgical treatment to increase femoral head coverage and decrease laxity of the dysplastic hip joint, however, the efficacy is less know. Client-owned dogs older than 6 months with clinical signs of coxofemoral joint subluxation and radiographic evidence of HD with no or mild osteoarthritis (OA) were included. The Norberg angle (NA), linear percentage of femoral head overlap (LFO), and percentage of femoral head coverage (PC) were investigated radiographically and with computed tomography (CT) before and after surgery. OA was graded (scores 0-3) according to the maximum osteophyte size measured on CT. In addition, joint laxity (Ortolani) test results, gait analysis, and the Helsinki chronic pain index (HCPI) questionnaire were obtained at preoperative, immediately postoperative and at 1.5- and 3-month evaluations. Acetabular rim extension was performed in 61 hips of 34 dogs; NA, LFO, and PC were significantly higher immediately postoperatively and at the 1.5- and 3-month follow-up examinations compared with preoperative values (p < 0.05). Osteophyte size gradually increased over time (p < 0.05). The OA score significantly increased between preoperatively and directly postoperatively, and between preoperatively and at 3-month follow-up (p < 0.05). The laxity test normalized in 59 out of 61 hips after surgery, and the HCPI questionnaire showed that the pain score decreased significantly at 1.5 and 3 months, postoperatively. The force plate showed no significant improvement during the 3 months follow-up. Although pain reduction by the implant was unclear in short-term results, a personalized shelf implant significantly increased femoral head coverage and eliminated subluxation of the dysplastic hip joint. Further studies are required to study the long-term efficacy of gait, chronic pain, and progression of osteoarthritis.

Radiographic quantification of the normal and near-normal coxofemoral conformation in Labrador Retrievers and German Shepherds: a comparative study

BackgroundCanine hip dysplasia (CHD) is a multifactorial disease affecting large breed dogs with associated joint laxity and incongruity that predisposes them to osteoarthritis. The purpose of the study is to objectively compare the conformation of normal and near-normal coxofemoral joints (CFJS) in Labrador Retrievers versus German Shepherds on the extended ventrodorsal radiograph. Investigated groups were categorized as normal and near-normal CFJS according to the morphometric criteria established by the FCI scoring system. Center-edge (CE) angle, Norberg angle (NA), indices of dorsal AFH coverage width and area, acetabular slope (AS) angle, and inclination angle were determined for each group. CE angle and AS angle were modified from previously described human techniques. The width and area of dorsal AFH coverage were standardized by the corresponding femoral head diameter and area. Variables were compared between groups using an unpaired, two-tailed t-test. A Spearman correlation coefficient determined the relationship between selected variables.ResultsIn Labradors, CE angle (lateral coverage) and dorsal AFH coverage area index (dorsal coverage) were greater in normal versus near-normal CFJS. In German Shepherds, lateral AFH coverage (CE angle and NA) was greater in normal versus near-normal hip joints; whereas, dorsal AFH coverage did not differ between the two groups. Lateral AFH coverage was greater in normal versus near-normal CFJS of both breeds. In Labradors, the inclination angle was greater in near-normal versus normal CFJS. Normal CFJS of Labradors revealed greater lateral and dorsal AFH coverages compared to German Shepherds. Near-normal joints of Labradors showed greater lateral AFH coverage compared to those of German Shepherds; whereas, dorsal AFH coverage did not differ between the two breeds. A steeper acetabular slope angle was noted in normal and near-normal CFJS of German Shepherds compared to Labrador Retrievers. The inclination angle of near-normal joints was greater in Labrador Retrievers compared to German Shepherds.ConclusionsOverall, normal and near-normal CFJS of German Shepherds had lesser AFH coverage and steeper acetabular slope angle compared to Labrador Retrievers. Labrador Retrievers and German Shepherds with CE-angles < 27° and < 21.8°, dorsal AFH coverage width indices < 51 and < 49%, and/or dorsal AFH coverage area indices < 53 and < 50%, respectively, may be consistent with CHD. Thus, the authors would recommend excluding subjects with lower values from breeding. Validating the reported measurements is still warranted.

Quantitative assessment of hip morphology to enhance the identification of hip dysplasia in German Shepherd Dogs

To develop quantitative measures that, when combined with the Fédération Cynologique Internationale (FCI) score, would potentially enhance the accuracy of the scoring process. 153 client-owned purebred German Shepherd Dogs with normal and near normal (71 dogs) and dysplastic coxofemoral joint (82 dogs). Center edge (CE) angle, Norberg angle (NA), indexes of dorsal acetabular femoral head (AFH) coverage width and area, acetabular index angle, and inclination angle were determined. We also investigated the correlation between selected variables. Coxofemoral joints were classified into normal, near normal, and mildly, moderately, and severely dysplastic joints based on the morphometric criteria previously established by the conventional FCI scoring. Variables were compared among the 5 groups using ANOVA. Linear relationships were determined using Spearman correlation coefficients. All radiographic measurements differed significantly (P < .0001) among the 5 assigned groups (normal, near normal, mildly dysplastic, moderately dysplastic, and severely dysplastic hip joints). NA was the only measure that differed significantly (P ≤ .03) between the 5 assigned groups. Positive correlations were identified between Norberg and CE angles (rs = 0.93), between width and area indexes of dorsal AFH coverage (rs = 0.92), and between the measurement techniques utilized to assess lateral versus dorsal AFH coverage (rs ≥ 0.65). Evaluation of lateral and dorsal AFH coverage may help to refine the scoring system used to select German Shepherd Dogs for breeding. German Shepherd Dogs with NA < 103°, CE angle < 20.8°, dorsal AFH coverage width index ≤ 49%, and/or dorsal AFH coverage area index ≤ 51% should be considered to have mild, moderate, or severe hip dysplasia and are therefore not good candidates for breeding. Borderline values between near normal and mildly dysplastic joints should be reevaluated.

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.

Simple SummaryHip dysplasia is the most common non-traumatic disease and cause of lameness in dogs. Different screening programs which use radiographic evaluation of the extended ventrodorsal projection of the hip exist for breeding selection. The Federation Cynologique International assigned five different scoring grades from A to E, ranging from a normal hip to severe dysplasia, to provide certification of the status of the joint. Of the different methods used for assessment, the Brass method is the most descriptive since it considers each part of the hip joint individually. The aim of the present study was to improve knowledge regarding the morphological changes in the context of hip dysplasia progression, especially in grades A to C. Some alterations were even found in grade A. The laxity and incongruence of the joint lead to the modification of the shape of the head and femoral neck, although some changes may be present in the normal or near normal hip joint. Some of the present findings, which were in contrast to the literature, are very interesting and additional investigation is indicated.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.

Inter-Observer Agreement in Radiographic Diagnosis of Coxofemoral Joint Disease in a Closed Cohort of Four-Month-Old Rottweilers.

Simple SummaryCanine hip dysplasia is an important orthopedic disorder in veterinary medicine. In addition to body weight, fat intake, rapid growth, and hormonal changes, heredity is one of its underlying factors. Diagnosis of hip dysplasia under one year of age would help veterinarians to plan proper preventive/therapeutic methods and exclude dysplastic dogs from breeding programs to reduce the incidence of the disease in future generations. Therefore, having an accurate method for the early diagnosis of dysplastic dogs is an important subject, and a limited number of screening methods are used globally. Assessment of the accuracy of these methods can be examined with intra- and inter-observer studies. In this study, we aimed to assess the inter-observer agreements of the eight radiographic parameters from four different radiographic projections between five experienced observers (two of them certified scrutineers for canine hip dysplasia) to evaluate the reproducibility of the protocols. In our study, high inter-observer agreements were recorded for measurable values such as angle measurements, whereas the results of the subjective grading were low. Thus, it can be deduced that quantitative parameters are reliable values and a combination of these values with other screening programs such as clinical examinations might increase the accuracy of the examinations.Canine hip dysplasia is a complex and multifactorial disease. The early diagnosis of dysplastic dogs under one year of age helps veterinarians to plan proper preventive/therapeutic methods. Having an accurate screening method increases the chance of the early detection of dysplasia. The goal of our study was to assess the inter-observer reliability of eight radiographic parameters in four-month-old Rottweilers. Radiographs of the 28 Rottweilers were investigated by five experienced observers. The radiographs were taken in ventrodorsal view with extended legs, frog-leg ventrodorsal view, distraction view, and dorsal acetabular rim view. Four quantitative parameters such as Norberg angle (NA), distraction index (DI), dorsal acetabular rim slope (DARS), and center edge angle (CEA) and four qualitative parameters such as sclerosis of the cranial acetabular rim (SCAR), location of the center of the femoral head (LCFH), grading of the degenerative joint disease (GDJD), and grading of the dorsal acetabular rim (GDAR) were evaluated. High inter-observer agreements were recorded for quantitative values, whereas the inter-observer agreement of the qualitative parameters was low. It can be deduced that the evaluated quantitative parameters are reliable, and a combination of these methods with clinical examinations might increase the accuracy of the examinations.

Inter- and Intra-Observer Variations in Radiographic Evaluation of Pelvic Limbs in Yorkshire Terriers with Cranial Cruciate Ligament Rupture and Patellar Luxation.

The main aims of the study were to describe bone alignment differences in Yorkshire Terriers (YT) with cranial cruciate ligament rupture (CCLR), patellar luxation (PL), or with a combination of both (CCLR + PL); to verify the theory of increased strain on cranial cruciate ligament (CrCL) due to PL as a predisposing factor; and to evaluate intra- and inter-observer variability of the protocols developed for measurement of femoral and tibial alignment in Yorkshire Terriers. Fifty-five hindlimbs of YT were divided into four groups: Control, CCLR, PL, and CCLR + PL. Thirty parameters were radiographically evaluated including hip joint, femoral, tibial, and intercondylar fossa (ICF) parameters. Three observers evaluated all parameters on two separate occasions with a twelve-week interval between measurements. Significant differences in conjunction with CCLR and PL theories between groups were noticed in: Norberg angle (NA), quadriceps angle (Qa), anatomic lateral distal femoral angle (aLDFA), femoral varus (FVA), mechanical cranial proximal tibial angle (mCrPTA), mechanical caudal proximal tibial angle (mCdPTA), tibial plateau angle (TPA), distal tibial axis/proximal tibial axis angle (DPA). Some interesting findings are the similarity of values between Control and CCLR vs. CCLR + PL and PL groups in Na, Qa, aLDFA; between CCLR + PL and PL in FVA and a significantly lower age of dogs in CCLR + PL compared to CCLR group. Based on our results, we can conclude that YT with different clinical findings have differing bone morphology. Moreover, these findings may support PL as a predisposing factor for CCLR in small breeds. Measurements in which excellent inter- observer agreement was achieved may be used for surgical planning or for further discussions.

Modified FCI (Fédération Cynologique Internationale) Scoring of the Coxofemoral Joint in Labrador Retrievers Without and With Hip Dysplasia.

The objective is to propose a modified FCI scoring protocol of the canine hip joint via: (1) providing morphometric criteria of each score; (2) quantifying the extent of lateral and dorsal acetabular femoral head (AFH) coverage; (3) evaluating the steepness of cranial acetabular edge (acetabular index angle) and inclination angle (IA) in normal and dysplastic coxofemoral joints of Labrador Retrievers. The long-term goal is to achieve a selective breeding protocol using parental phenotypically healthy coxofemoral joints based on the standard extended-leg VD radiograph to help reduce the prevalence of CHD among offspring. Investigated populations were classified into normal (grade A) and dysplastic coxofemoral joints (grades B to E) based on the morphometric criteria previously established by the conventional FCI scoring system. Center-edge (CE) angle, Norberg angle (NA), indices of dorsal AFH coverage width and area, acetabular index angle, and inclination angle were determined for each group. Variables were compared between groups using ANOVA. Spearman correlation coefficient was used to determine the linear relationship between selected variables. Overall, all radiographic measurements differed significantly (P < 0.0001) among the five tested groups using ANOVA test. Dorsal AFH coverage area index was the only measure that differed significantly (P ≤ 0.007) between every two consecutive groups using Tukey's test. Significant correlations were identified between the Norberg and CE angles (rs = 0.95, P < 0.0001), the width and area of dorsal AFH coverage (rs = 0.96, P < 0.0001), and the radiographic techniques utilized to assess lateral vs. dorsal AFH coverage (rs ≥ 0.80, P < 0.0001). Evaluation of CE-angle, dorsal AFH coverage area index and acetabular index angle is recommended during selective breeding to include parents with radiographically healthy joints and reduce the incidence of hip dysplasia among offspring. Dogs with CE-angle <27°, dorsal AFH coverage area index <53%, and/or acetabular index angle >9° may be consistent with hip dysplasia and are recommended to be excluded from potential breeding groups. Re-evaluation of coxofemoral joints with borderline values located between near-normal and mildly dysplastic coxofemoral joints is strongly recommended to be performed after 6 months.

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

To report the short-term outcome of double pelvic osteotomy (DPO) in dogs with canine hip dysplasia ≥10 months of age. Case series. Eleven hips in eight dogs aged between 10 to 28 months. 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. 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. Double pelvic osteotomy improved joint congruity and clinical signs in dogs affected by hip dysplasia without osteoarthritis that were ≥10months of age. Double pelvic osteotomy may be a treatment option for dogs with hip dysplasia ≥10months of age. A large study assessing long-term outcomes is indicated.

Genomic Prediction of Two Complex Orthopedic Traits Across Multiple Pure and Mixed Breed Dogs.

Canine hip dysplasia (CHD) and rupture of the cranial cruciate ligament (RCCL) are two complex inherited orthopedic traits of dogs. These two traits may occur concurrently in the same dog. Genomic prediction of these two diseases would benefit veterinary medicine, the dog’s owner, and dog breeders because of their high prevalence, and because both traits result in painful debilitating osteoarthritis in affected joints. In this study, 842 unique dogs from 6 breeds with hip and stifle phenotypes were genotyped on a customized Illumina high density 183 k single nucleotide polymorphism (SNP) array and also analyzed using an imputed dataset of 20,487,155 SNPs. To implement genomic prediction, two different statistical methods were employed: Genomic Best Linear Unbiased Prediction (GBLUP) and a Bayesian method called BayesC. The cross-validation results showed that the two methods gave similar prediction accuracy (r = 0.3–0.4) for CHD (measured as Norberg angle) and RCCL in the multi-breed population. For CHD, the average correlation of the AUC was 0.71 (BayesC) and 0.70 (GBLUP), which is a medium level of prediction accuracy and consistent with Pearson correlation results. For RCCL, the correlation of the AUC was slightly higher. The prediction accuracy of GBLUP from the imputed genotype data was similar to the accuracy from DNA array data. We demonstrated that the genomic prediction of CHD and RCCL with DNA array genotype data is feasible in a multiple breed population if there is a genetic connection, such as breed, between the reference population and the validation population. Albeit these traits have heritability of about one-third, higher accuracy is needed to implement in a natural population and predicting a complex phenotype will require much larger number of dogs within a breed and across breeds. It is possible that with higher accuracy, genomic prediction of these orthopedic traits could be implemented in a clinical setting for early diagnosis and treatment, and the selection of dogs for breeding. These results need continuous improvement in model prediction through ongoing genotyping and data sharing. When genomic prediction indicates that a dog is susceptible to one of these orthopedic traits, it should be accompanied by clinical and radiographic screening at an acceptable age with appropriate follow-up.

English

Hip dysplasia in cats appears to have a similar prevalence as that seen in dogs especially with large breeds of cats like the Maine coon. However, cats do not commonly show signs of lameness like dogs do. This study was to determine the prevalence of hip dysplasia in domestic shorthair breed of cats in three municipal districts in Accra, Ghana. Twenty (12 males and 8 females) adult (2.3 &plusmn; 0.8 years) shorthair breed of cats of both gender weighing 1.7 &plusmn; 0.4 kg were included in this study. They were sedated with xylazine and atropine injection prior to radiography. Extended and frog-leg ventro-dorsal radiographs were taken using a manual processing x-ray machine. Norberg angles (NA), joint space scores and subjective morphological alterations for each hip were assessed. Comparisons were made for the NA scores within gender, between gender, between the right and left hips using Independent t-test. The relationship between the joint space scores and weight, age or gender of the cats was assessed. The morphological changes were also assessed. Mean manual Norberg angle measurements for 19 cats were 93.67 &plusmn; 1.9&deg; and mean digital Norberg angle measurements for 19 cats was 102.35 &plusmn; 1.1&deg;. One cat with complete cranio-dorsal luxation, due to history of preceding accident had manual Norberg angle of 38&deg; and digital Norberg angle of 45&deg;. Two cats displayed mild subluxation of the hip joint. There was no considerable difference in the NA or joint space measurements. This study found a ten percent prevalence of hip dysplasia in domestic shorthair breed of cats in the three Municipal Districts in Accra, Ghana. Both manual and digital methods for measuring the NA provided results which were within similar ranges. Key words: cats, hip dysplasia, radiographs, prevalence, shorthair, domestic. &nbsp

Patient‐specific 3D‐printed shelf implant for the treatment of hip dysplasia: Anatomical and biomechanical outcomes in a canine model

A solution for challenging hip dysplasia surgery could be a patient‐specific 3D‐printed shelf implant that is positioned extra‐articular and restores the dysplastic acetabular rim to normal anatomical dimensions. The anatomical correction and biomechanical stability of this concept were tested in a canine model that, like humans, also suffers from hip dysplasia. Using 3D reconstructed computed tomography images the 3D shelf implant was designed to restore the radiological dysplastic hip parameters to healthy parameters. It was tested ex vivo on three dog cadavers (six hips) with hip dysplasia. Each hip was subjected to a biomechanical subluxation test, first without and then with the 3D shelf implant in place. Subsequently, an implant failure test was performed to test the primary implant fixation. At baseline, the dysplastic hips had an average Norberg angle of 88 ± 3° and acetabular coverage of 47 ± 2% and subluxated at an average of 83 ± 2° of femoral adduction. After adding the patient‐specific shelf implants the dysplastic hips had an average Norberg angle of 122 ± 2° and acetabular coverage of 67 ± 3% and subluxated at an average of 117 ± 2° of femoral adduction. Implant failure after primary implant fixation occurred at an average of 1330 ± 320 Newton. This showed that the patient‐specific shelf implants significantly improved the coverage and stability of dysplastic hips in a canine model with naturally occurring hip dysplasia. The 3D shelf is a promising concept for treating residual hip dysplasia with a straightforward technology‐driven approach; however, the clinical safety needs to be further investigated in an experimental proof‐of‐concept animal study.

Juvenile pubic symphysiodesis associated with pectineus myectomy for treatment of hip dysplasia in dog

Background: Hip dysplasia (HD) is the most common non-traumatic orthopedic disease in large breed dogs. Treatment is chosen according to the severity of the condition, the age of the dog and the involvement of osteoarthritis (OA). For puppies up to 20-weeks-old, surgical treatment by the juvenile pubic symphysiodesis (JPS) technique can be performed. This procedure promotes the ventrolateral rotation of the acetabulum over the femoral head, which improves hip joint congruence and stability. The objective of this study is to report the case of a young dog with HD treated with JPS and pectineus myectomy. Clinical and radiographic outcomes were assessed for up to one year after surgery.Case: A 17-week-old Saint Bernard puppy was attended at the University Veterinary Hospital showing abnormal weight bearing and lameness in pelvic limbs, without history of previous trauma. On orthopedic examination, there was a marked hypotrophy of the pelvic limb muscles, severe pain and laxity in the hip joints, and positive feature in the Ortolani test. The hip joint subluxation angle (SA) and reduction angle (RA) were measured. A radiographic study was carried out to evaluate the hip joints and measure the Norberg angle (NA), distraction index (DI), acetabular angle (AA) and dorsal acetabular rim angle (DARA). The 20-week-old dog underwent surgical treatment by JPS technique. A ventral surgical approach to the pubis was performed and the pubic symphysis was cauterized with electrocautery. Partial pectineus myectomy technique was also performed. Drug therapy and restriction of physical activities were indicated in the early postoperative. The dog was evaluated by clinical and radiographic examinations at 4 months and 1 year after the surgical procedure. In the reassessment after 4 months of surgical treatment, the patient showed improvement in clinical signs, with mild lameness and absence of painful sensitivity in the movement of the hip joints. Radiographically, hip joint incongruity was observed, but with progressive improvement in the values of the measured variables. In the clinical examination 1 year after the procedure, the dog showed satisfactory weight bearing with slight lameness in pelvic limbs in the running gait. There was improvement in the thigh muscles and no painful signs were observed in the hip joints, but a positive result was detected in the Ortolani test. In the radiographic examination, bilateral articular incongruity was still observed, however, there was a mild improvement in the coverage of the acetabulum over the femoral head. The measured angles and indices showed favorable results regarding the recovery of hip joint stability and proper development.Discussion: Studies evaluating the JPS technique for the treatment of HD have shown to be a relatively simple and effective procedure, which allows altering the acetabular coverage, reducing the development of HD and the progression of OA. The need for an early diagnosis of this condition is essential, so that the JPS technique can be used in young dogs and offer effective results. In the present report, in the late postoperative period, the dog showed improvement in clinical signs, with favorable weight bearing and ambulation in pelvic limbs, recovery of limb muscles, absence of pain in the hip joints and decrease in RA and SA. Radiographically, the reduction in joint subluxation, improvement in acetabular coverage over femoral heads, increase in NA and AA, reduction in DI and DARA are evidence of the favorable outcome of ventrolateral rotation of the acetabulum after surgical treatment. The surgical technique used was effective, which enabled the dog to recover the functional use of the pelvic limbs and improve the quality of life.Keywords: hip dysplasia, juvenile pubic symphysiodesis, hip joint, osteoarthritis, dog.Título: Sinfisiodese púbica juvenil associada à miectomia do pectíneopara tratamento de displasia coxofemoral em cãoDescritores: displasia coxofemoral, sinfisiodese púbica juvenil, coxofemoral, osteoartrite.