Effects of intertrochanteric varus osteotomy on Norberg angle and percent coverage of the femoral head in displastic dogs

This study was conducted to assess the effects of femoral varus osteotomy on joint congruency in dogs affected by early stage hip dysplasia. Preoperative planning to move the femoral head within the acetabulum was carried out. Varisation of the femoral inclination angle (fIA) was achieved by Intertrochanteric Osteotomy (ITO). Norberg angle (NA), percent coverage (PC) of the femoral head by the acetabulum and fIA was measured from preoperative, immediate postoperative and first and second recheck radiographs of seven dogs that underwent an ITO (joint n = 9). There was significant (p < 0.05) improvement of both NA and PC in all patients as indicated by a change in the mean ± standard deviation of 78.9° ± 7.5 and 36.9% ± 5.2 to 92.2° ± 6.7 and 50.6% ± 8.3, respectively. No significant difference (p < 0.05) was observed between the values of the planned femoral inclination angle (pfIA) of the femur and the effective femoral inclination angle (efIA) obtained after surgery (115.9° ± 2.5 and 111.3° ± 6.4, respectively). These findings could encourage the use of ITO in veterinary practice and indicate that intertrochanteric varus osteotomy should be re-considered for the treatment of early stage hip dysplasia in dogs with radiological signs of joint incongruency.     

Evaluation of the Norberg angle threshold: a comparison of Norberg angle and distraction index as measures of coxofemoral degenerative joint disease susceptibility in seven breeds of dogs

OBJECTIVE: To evaluate the thresholds of 2 radiographic methods used to determine coxofemoral joint laxity in 7 breeds of dogs. ANIMALS: Three hundred and fifty clinically normal dogs. STUDY DESIGN: Retrospective study. METHODS: Hip radiographs from 7 breeds of dogs were randomly selected from a database. None of the dogs had radiographic evidence of degenerative joint disease (DJD). Distraction index (DI) and Norberg angle (NA) were measured on these radiographs and compared with DI and NA thresholds for diagnosing DJD susceptibility derived from the literature and from evaluated Borzois. Dogs with a NA<105 degrees and a DI of < or =0.32 were considered false-positives and dogs with a NA> or =105 degrees and a DI of >0.32 were considered false-negatives. RESULTS: Mean age of all dogs was 22.9 months. Mean NA for all dogs was 99.37 degrees, and mean DI for all dogs was 0.44. Borzoi mean DI of was significantly less than the mean DI of the other 6 breeds. The highest (most hip laxity) Borzoi DI was 0.32, and the lowest (most hip laxity) Borzoi NA was 99 degrees. False-positive and false-negative diagnoses were identified in 6 of the 7 breeds. CONCLUSIONS: Using the NA threshold of 105 degrees (literature established threshold of susceptibility to DJD) resulted in a high percentage of false-negative and false-positive diagnoses. Breeds like the Labrador Retriever and Rottweiler would have large numbers of hip dysplasia susceptible dogs remain in the breeding population based on this NA threshold. False-positive diagnoses were common in breeds like the Australian Shepherd, Borzoi, and German Shepherd effectively eliminating hip dysplasia nonsusceptible dogs from the breeding population. CLINICAL RELEVANCE: The NA was not an accurate predictor of DJD susceptibility in these 7 breeds of dogs when using a NA threshold of 105 degrees.     

Comparison of femoral inclination angle measurements in dysplastic and nondysplastic dogs of different breeds

In this study, inclination angle of the femoral head and neck was measured on 484 limbs of 242 dogs belonging to 7 breeds, examined for hip dysplasia. These inclination angles were compared according to age, sex and joint laxity, evaluated with Subluxation Index (SI) and Norberg angle (NA) results. The findings indicate that (a) there was a minimal (nonsignificant) difference in femoral inclination angle between the dysplastic and nondysplastic dogs belonging to 7 breeds; (b) although there was no significant difference in femoral inclination angle between the nondysplastic dogs belonging to 4 breeds (Pointer, Irish Setter, Golden Retriever and German Shepherd), a significant difference was observed between Doberman and Labrador, and between Anatolian Karabash and the other six breeds (p < 0.001). Age and sex did not affect the femoral neck angle.     

Measurement of femoral angles in four dog breeds

Objective— To develop a standard method of measurement for femoral angles and report values for normal Labrador Retrievers, Golden Retrievers, German Shepherds, and Rottweilers.
Study Design— Retrospective evaluation of canine pelvis and femoral radiographs.
Sample Population— Radiographs of Labrador Retrievers, Golden Retrievers, German Shepherds, and Rottweilers (n=100 for each breed).
Methods— Anatomic lateral distal and proximal femoral angle, mechanical lateral distal and proximal femoral angle, and femoral angle of inclination were measured from radiographs.
Results— For the 4 breeds (Labrador Retrievers, Golden Retrievers, German Shepherds, and Rottweilers, respectively) anatomic lateral distal femoral angles were 97°, 97°, 94°, and 98°; mechanical lateral distal femoral angles were 100°, 100°, 97°, and 100°; anatomic lateral proximal femoral angles were 103°, 98°, 101°, and 96°; mechanical lateral proximal femoral angles were 100°, 95°, 97°, and 93°; and inclination angles were 134°, 134°, 132°, and 137°. Labrador Retrievers, Golden Retrievers, and Rottweilers had significantly higher values for both anatomic and mechanical lateral distal femoral angle than German Shepherds. Anatomic and mechanical lateral proximal angles were greatest for Labrador Retrievers and lowest for Rottweilers.
Conclusion— Anatomic and mechanical femoral joint angles vary between breeds of dogs.
Clinical Relevance— Values for femoral joint angles may be clinically useful for angular limb deformity diagnosis, treatment, and assessment.     

Relationships between results of the Ortolani method of hip joint palpation and distraction index, Norberg angle, and hip score in dogs

OBJECTIVE: To determine whether results of the Ortolani method of hip joint palpation in dogs were related to distraction index (DI), Norberg angle, or radiographic hip score. DESIGN: Cross-sectional study. ANIMALS: 459 clinically normal dogs. PROCEDURE: Dogs were sedated for radiography and palpation of the hip joints. Results of hip joint palpation were classified as negative, mild positive, moderate positive, or severe positive. Distraction indices were measured for all dogs. Norberg angles were measured for 380 dogs for which ventrodorsal hip-extended radiographic projections were available. Hip scores assigned by the Orthopedic Foundation for Animals (OFA) were available for 95 dogs. RESULTS: Age, weight, and sex were not significantly associated with results of hip joint palpation. There was moderate correlation between results of hip joint palpation and DI (r = 0.636), low-moderate correlation between results of hip joint palpation and OFA hip scores (rs = 0.437), and weak negative correlation (r = -0.236) between results of hip joint palpation and Norberg angle. For joints without degenerative joint disease (DJD), there was a significant linear relationship between results of hip palpation and DI; however, for joint with DJD, there was not. Results of hip joint palpation were 5.3-fold as likely to be negative for dogs with DJD as for dogs without. CLINICAL IMPLICATIONS: Results of hip joint palpation were at best moderately correlated with radiographic measures of hip joint laxity. Therefore, hip joint palpation should be combined with hip-extended and stress radiography when assessing hip joint quality.     

Comparison of radiographic and anatomic femoral varus angle measurements in normal dogs

Objective— To determine if the clinically practiced method of radiographic femoral varus angle (R-FVA) measurement is repeatable, reproducible, and accurate.
Study Design— Radiographic and anatomic study.
Animals/Sample Population— Normal Walker hound cadavers (n=5) and femora (n=10).
Methods— Cadavers were held in dorsally-recumbent and torso-elevated positions as 3 craniocaudal radiographs were made of each femur, by each of 2 different technicians. Femora were then harvested for direct measurement of anatomic femoral varus angle (A-FVA). R-FVA was measured on each radiograph by each of 3 examiners on 3 separate occasions. Intra-observer (repeatability) and inter-observer (reproducibility) variance in R-FVA measurement and the strength of relationship between R-FVA and A-FVA (accuracy) were determined.
Results— Mean (±SD) A-FVA was 5.2±2.1° (range, 2.4–8.2°). Mean (±SD) R-FVA was 5.8±1.0° (range, 2.7–9.6°). Intra-observer variance (range: 11–16%) and inter-observer variance (16%) were acceptable. The strength of relationship between measured R-FVA and A-FVA (maximum adjusted R²<0) was unacceptably low regardless of observer, patient position, or radiographic technician.
Conclusion— R-FVA measurement was repeatable and reproducible, but not statistically accurate in predicting A-FVA in these 5 normal Walker hounds. The detected inaccuracy may be real or the result of a selection bias for normal dogs obscuring the true relationship.
Clinical Relevance— R-FVA may not be an accurate method of femoral varus measurement in dogs with A-FVA<10°. Using Slocum's criteria for distal femoral osteotomy (R-FVA>10°), the procedure would not have been erroneously performed in any of the normal dogs of this study.     

A longitudinal study on diarrhoea and vomiting in young dogs of four large breeds

Background

Prospective studies to document the occurrence of canine diarrhoea and vomiting are relatively scarce in dogs, and the majority of published studies are based on information from clinical records. This study investigates the incidence risk of diarrhoea and vomiting as well as potential risk factors.

Methods

A cohort study of 585 privately owned dogs of four breeds: Newfoundland, Labrador retriever, Leonberger, and Irish wolfhound. The owners maintained a continuous log regarding housing, exercise, nutrition, and health of their dogs. Episodes of diarrhoea and vomiting were recorded in a consecutive manner in a booklet. The owners completed the questionnaires and reported information at three, four, six, 12, 18, and 24/25 months of age, called observational ages.Associations with potential risk factors for diarrhoea and vomiting were investigated in separate generalized estimating equation analyses.

Results

The incidence of both diarrhoea and vomiting was influenced by breed. Both diarrhoea and vomiting were relatively common in young dogs, occurring most frequently during the first months of life. After three months of age, the odds of diarrhoea were significantly lower when compared to the observational period seven weeks to three months (OR ranging from 0.31 to 0.70 depending on the period). More males than females suffered from diarrhoea (OR = 1.42). The occurrence of diarrhoea was more common in dogs that also experienced episode(s) of vomiting during the study period (OR = 5.43) and vice versa (OR = 5.50). In the majority of dogs episodes of diarrhoea and vomiting did not occur at the same time. Dogs in urban areas had higher odds (OR = 1.88) of getting diarrhoea compared to dogs living in rural areas. The occurrence of both diarrhoea and vomiting demonstrated a seasonal variation with higher incidence during the summer months.

Conclusion

Both diarrhoea and vomiting occurred most frequently during the first months of life. The incidence of diarrhoea and vomiting was significantly different between breeds. Diarrhoea occurred more frequently in males and in dogs living in urban areas. Also, a positive association between the occurrence of diarrhoea and vomiting in the same dog was found.     

Magnetic resonance imaging of the femoral head of normal dogs and dogs with avascular necrosis.

The purpose of this study was to describe the appearance of the femoral head of normal, young, small breed dogs, and dogs with avascular necrosis using low-field (0.3 T) magnetic resonance (MR) imaging. Images of the femoral heads were obtained in the dorsal plane, and included T1-weighted spin-echo, T2-weighted fast spin-echo, fast spin echo-inversion recovery, and fluid attenuated inversion recovery pulse sequences. MR imaging features of the asymptomatic femoral heads and necks included uniform high signal intensity compared with muscle on T1- and T2-weighted images. There was either uniform enhancement or no enhancement on postcontrast T1-weighted images. The MR imaging findings of dogs affected with avascular necrosis differed from those of asymptomatic dogs. Typically, the affected dogs had inhomogeneous intermediate to low-signal intensity within the femoral head and neck compared with muscle on T1-weighted images, inhomogeneous enhancement of the femoral head and/or neck on postcontrast T1-weighted images, and inhomogeneous low- to high- signal intensity within the femoral head and neck on T2-weighted images.     

Delayed ossification of the femoral head in dogs with hip dysplasia

In humans, delayed ossification of the caput femoris is often seen associated with hip dysplasia in babies. This phenomenon may possibly exist in dogs. In this study, the radiographic appearance of the caput femoris of 13 German shepherd dogs was examined. The dogs underwent pelvic radiography at the age of 14 to 15 days, six weeks, and 12 months. A significant relationship was shown between hip dysplasia and the late appearance of the epiphysis of the caput femoris (P=0–02). At the age of 14 to 15 days it was not possible to see both epiphyses in 54 per cent of the dogs. All of these dogs had hip dysplasia when they were 12 months old. This was in contrast to the six dogs which had both epiphyses visible when they were 14 to 15 days old. At 12 months of age, four of these dogs (67 per cent) did not show any sign of hip dysplasia.     

Statistical analysis of individual assignment tests among four cattle breeds using fifteen STR loci

Assignment tests based on multilocus genotypes are becoming increasingly important to certify quality and origin of livestock products and assure food safety and authenticity. The purpose of this study was to determine the potential of microsatellites (STR) for determining the breed origin of beef products among cattle breeds present in the market. We typed 19 STR in 269 animals from 4 cattle breeds. Based on Wright's F-statistics, 4 loci were discarded, and the remaining 15 loci (FIT = 0.101, FST = 0.089, and FIS = 0.013) were used to compute the likelihood that each multilocus genotype of the total sample was drawn from its true breed instead of another breed. To avoid occurrence of zero likelihood when one or more alleles were missing from a tested breed, sample allele frequencies were estimated assuming uniform prior distributions. Log-likelihood ratio [log(LR)] distributions of the individual assignments were determined for all possible breed contrasts, and their means and SD were used to infer the true-positive and false-positive rates at several values of the log(LR). The posterior probability that the animals of a presumed breed were actually drawn from that breed instead of any another breed was then calculated. Given an observed value of log(LR) > 0 and assuming equal priors, these probabilities were > 99.5% in 10 of 12 possible breed contrasts. For the 2 most closely related breeds (FST = 0.041), this probability was 96.3%, and the probability of excluding the origin of an animal from an alleged breed when it was actually derived from another breed was similar.     

A longitudinal study on growth and growth variables in dogs of four large breeds raised in domestic environments

The main objective of this study was to describe the growth patterns of 4 large dog breeds [Newfoundland (NF), Labrador retriever (LR), Leonberger (LEO), and Irish wolfhound (IW)] raised in domestic environments and concomitant changes in 2 growth-related clinical variables: total serum alkaline phosphatase (ALP) and the circumference of the distal radius and ulna (CDRU). The second objective was to investigate whether these measurements were affected by a range of independent variables like age, sex, litter number, and birth weight. Seven hundred dogs were included in the study, and BW data, separated by breed and sex, were fitted to the Gompertz function. Birth weight, adjusted for litter number, differed significantly between sexes for 3 breeds (LEO, P = 0.004; NF, P = 0.02; LR, P = 0.009) and approached significance for IW (P = 0.07). Estimated mean BW increased rapidly during the first 100 d after birth in all 4 breeds, then plateaued, with maturity being reached between 351 (female LR) and 413 d (male NF). Estimated mature BW ranged from 30.8 kg for the female LR up to 65.7 kg for the male IW. Weight gain, as expressed by the derivative of the Gompertz function, reached its peak in the smallest breed (LR) at the youngest age, 89 d for the females and 95 d for males. Log-transformed BW was significantly related to age, breed, and sex, and the age x sex and age x breed interactions. Within breeds, age, birth weight, and litter number had a significant effect on log-transformed BW. The estimated average CDRU increased from 90 d of age toward a peak at 180 d. Thereafter, CDRU declined and stabilized at about 1 yr of age. The estimated total ALP concentrations decreased from 90 to 360 d of age, after which they stabilized, at mean concentrations varying among breeds from 98 to 131 IU/L. Maximum least squares mean total ALP concentrations were found at 3 mo of age in all breeds, with the greatest least squares mean concentration in the IW breed (713 IU/L). In a mixed model analysis of the complete data set, total ALP was affected (P < 0.001) by age, breed, and the interaction of age x breed. This study described the main factors influencing growth and provided reference data for other studies, including those related to nutrition and disorders of growth.     

Treatment of medial patellar luxation by femoral closing wedge ostectomy using a distal femoral plate in four dogs

This case report describes the treatment of recurrent medial patellar luxation associated with varus deformity of the distal femur by distal femoral ostectomy stabilised using a distal femoral plate. Four dogs (five affected limbs) were included in the study. All cases had received previous surgery for medial patellar luxation but remained significantly lame. All were treated by femoral ostectomy to correct distal femoral varus deformity with application of a distal femoral bone plate. All cases improved following surgery. An excellent outcome was recorded in four of five cases. Lameness persisted in one case despite satisfactory patellar stability as a result of concurrent cranial cruciate ligament deficiency. One case suffered implant failure. Femoral ostectomy is an effective treatment for medial patellar luxation associated with femoral varus deformity. The distal femoral plate provides a convenient method by which to stabilise the ostectomy. Care should be exercised when the 2 mm distal femoral plate is applied.     

Assessment of bone mineral density of the femoral head in dogs with early osteoarthritis

OBJECTIVE: To compare the bone mineral density (BMD) of the proximal portion of the femur in dogs with and without early osteoarthritis secondary to hip dysplasia. ANIMALS: 24 dogs (3 Greyhounds, 6 Labrador-Greyhound crossbreeds, and 15 Labrador Retrievers). PROCEDURE: Computed tomography (CT) of the pelvis, including a bone-density phantom, was performed for each dog. Centrally located transverse CT slices and a computer workstation were used to identify 16 regions of interest (ROIs) in the proximal portion of the femur. For each ROI, the mean Hounsfield unit value was recorded; by use of the bone-density phantom and linear regression analysis, those values were converted to equivalent BMD (eBMD). Mean eBMD values for the subchondral and nonsubchondral ROIs in dogs with and without osteoarthritis (determined at necropsy) were compared. A mixed-model ANOVA and post hoc linear contrasts were used to evaluate the effects of osteoarthritis, breed, and sex on the BMD value. RESULTS: At necropsy, osteoarthritis was detected in 14 hip joints in 9 dogs; all lesions included early cartilage fibrillation. After adjusting for breed and sex, eBMD in subchondral ROIs 8 and 12 (adjacent to the fovea) were 8% and 6% higher, respectively, in osteoarthritis-affected dogs, compared with unaffected dogs; in the nonsubchondral ROIs, eBMD was 10% higher in osteoarthritis-affected dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with findings in unaffected dogs, increased eBMD in hip joints of dogs with early osteoarthritis supports a strong relationship between the subchondral and epiphyseal regions and articular cartilage in the pathogenesis and progression of osteoarthritis.     

Tibial plateau angle in four common canine breeds with cranial cruciate ligament rupture, and its relationship to meniscal tears

OBJECTIVES: To compare tibial plateau angle (TPA) among Labrador Retrievers, Rottweilers, Boxers, and German Shepherd Dogs that had undergone tibial plateau leveling osteotomies (TPLO) for cranial cruciate ligament disease, and to determine if higher TPAs are associated with increased risk for concurrent meniscal injury. METHODS: This was a retrospective study including 275 client-owned dogs of one of the four aforementioned breeds that received TPLO radiographs between 1999 and 2005 prior to undergoing the TPLO procedure. The TPA measured by the original surgeon was compared among four breeds and analyzed with respect to presence or absence of meniscal injury diagnosed via arthroscopy or arthrotomy at the time of surgery. RESULTS: Labrador Retrievers, Rottweilers, Boxers, and German Shepherd Dogs had mean TPAs of 25.9 degrees , 26.2 degrees , 25.9 degrees , and 28.2 degrees , respectively. The TPA of German Shepherd Dogs was significantly higher than that of the other breeds of dogs examined. TPA higher than the mean for dogs in this study did not significantly increase the risk for concurrent meniscal injury. CLINICAL SIGNIFICANCE: German Shepherd Dogs with cranial cruciate ligament disease had a significantly higher TPA compared to the other breeds examined. Higher TPA did not increase the likelihood of meniscal tears in this study. However, several variables that were not assessed, including the degree of cranial cruciate ligament integrity at the time of surgery and the time between original CrCL deficiency and surgical assessment, could have affected this analysis.     

Anatomical and ultrasonographic study of the femoral nerve within the iliopsoas muscle in beagle dogs and cats

ObjectivesAn ultrasound (US)-guided ventral suprainguinal approach to block the femoral nerve (FN) within the iliopsoas muscle (IPM) has recently been described in dogs. The goal of the present study was to provide the operator with additional information to locate the FN within the IPM in dogs and cats using US.Study designThe study was carried out in three phases: a dissection of the FN (phase 1); an in vivoUS-assisted nerve study (phase 2), and an anatomical cross-sectional study (phase 3).AnimalsNine healthy adult beagle dogs and nine healthy adult cats.MethodsDissections were performed to investigate the anatomical characteristics of the FN and its related structures in one dog and one cat. Ultrasound scans of the left and right FN were performed in eight dogs and eight cats. The FN diameter and the distance between the FN and the external iliac artery (EIA) in US images and in anatomical cryosections were measured.ResultsThe median FN diameter did not differ significantly between cats and dogs (1.1 mm versus 1.0 mm) or between the two techniques (US versus anatomical cross-sectional study) (1.1 mm versus 1.1 mm in dogs; 1.0 mm versus 1.1 mm in cats). The US and anatomical measurements of the median distances between the FN and EIA differed significantly between dogs and cats (8.2 mm versus 5.8 mm by US; 5.7 mm versus 4.8 mm in the anatomical study).Conclusions and clinical relevanceThe distance between the EIA and FN is reproducible in beagle dogs and cats and can be used in locating the FN within the IPM.     

Effect of sagittal plane positioning errors on measurement of the angle of inclination in dogs.

Angles of inclination were calculated from ventrodorsal (VD) and caudocranial horizontal beam (CaCrHB) radiographs of 17 anesthetized dogs, and from radiographs of left femurs of the same dogs positioned 0 degree, 10 degrees, 15 degrees, and 20 degrees from the cassette in the sagittal plane. Angles of inclination also were measured directly from radiographs of the bones rotated to correct for anteversion. Calculated angles of inclination from the bones at 10 degrees, 15 degrees, and 20 degrees from the cassette were significantly different from the 0 degree values obtained by calculation and direct measurement. Inclination angles from live dogs were consistently larger than those from 0 degree bones. Differences between angles of inclination calculated from VD and CaCrHB radiographs of live dogs were not significant.