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.     

New concepts of coxofemoral joint stability and the development of a clinical stress-radiographic method for quantitating hip joint laxity in the dog

From mechanical principles and postmortem observations of coxofemoral joints of dogs, a hydrostatic mechanism influencing hip joint stability was discovered. This discovery led to the development of a stress-radiographic positioning method to quantitate hip joint laxity in dogs. The method incorporated 2 views with the dog in supine position and hips at neutral flexion/extension angle: a compression view, with the femoral heads fully seated in the acetabula; and a distraction view, with the femoral heads at maximal lateral displacement. An index measurement method was formulated to quantitate the relative degree of joint laxity appearing in either the compression or distraction view. Clinical evaluation of 6 dogs was done to compare the compression/distraction method with the standard hip-extended radiographic method. Also, the stress-radiographic method was performed on 16-week-old Borzoi and German Shepherd Dogs to compare the characteristics of inherent hip joint laxity in these breeds. In all dogs tested, hip joint laxity was masked by the standard hip-extended view as indicated by a 2.5-fold improvement in sensitivity to hip joint laxity of the new method (P less than 0.00001). Moreover, the mean hip joint laxity of 16-week-old German Shepherd Dogs exceeded the mean hip joint laxity of Borzois by 79% (P less than 0.00001). Reports in the literature document the incontrovertible association of hip joint laxity to the development of hip dysplasia in dogs. We believe the ability to accurately quantitate hip joint laxity will provide key diagnostic and prognostic criteria for the selection of pet dogs, and more importantly, breeding stock.     

Distraction index as a risk factor for osteoarthritis associated with hip dysplasia in four large dog breeds*

Objective : To determine if age, breed, gender, weight or distraction index (DI) influenced the risk of radiographic osteoarthritis (OA) of canine hip dysplasia (CHD) in four common dog breeds; the American bulldog, Bernese mountain dog, Newfoundland and standard poodle. Materials and Methods : This was a cross sectional prevalence study with 4349 dogs. Canine hips were evaluated using 3 radiographic projections: the hip-extended view, the compression view and the distraction view. The hip-extended view was examined for the presence of OA. The PennHIP distraction view was utilized to calculate the DI. For all breeds, a multiple logistic regression model incorporating age, weight, gender, and DI was created. For each breed, disease-susceptibility curves grouping dogs on the basis of age were constructed. Receiver-operating characteristic (ROC) curves were developed for each breed regardless of age. Results : For all breeds, DI was the most significant risk factor for the development of OA associated with CHD. Weight and age were also significant risk factors in all four breeds, but gender was not. Clinical Significance : Results from this study support previous findings, that irrespective of breed, the probability of radiographic OA increases with hip joint laxity as measured by the DI. Breed-specific differences in this relationship, however, warrant investigation of all breeds affected by CHD to determine inherent dependency of hip OA on joint laxity. Such findings guide veterinarians in helping dog breeders to make evidence-based breeding decisions and in informing dog owners to implement preventative treatments for CHD for dogs found to be at risk.     

Evaluation of risk factors for degenerative joint disease associated with hip dysplasia in German Shepherd Dogs, Golden Retrievers, Labrador Retrievers, and Rottweilers.

OBJECTIVE: To determine whether age, breed, sex, weight, or distraction index (DI) was associated with the risk that dogs of 4 common breeds (German Shepherd Dog, Golden Retriever, Labrador Retriever, Rottweiler) would have radiographic evidence of degenerative joint disease (DJD) associated with hip dysplasia. DESIGN: Cross-sectional prevalence study. ANIMALS: 15,742 dogs. PROCEDURE: Hips of dogs were evaluated radiographically by use of the ventrodorsal hip-extended view, the compression v ew, and the distraction view. The ventrodorsal hip-extended view was examined to determine whether dogs had DJD. For each breed, a multiple logistic regression model incorporating age, sex, weight, and DI was created. For each breed, disease-susceptibility curves were produced, using all dogs, regardless of age, and dogs grouped on the basis of age. RESULTS: Weight and DI were significant risk factors for DJD in all breeds. For German Shepherd Dogs, the risk of having DJD was 4.95 times the risk for dogs of the other 3 breeds combined. In all breeds, the probability of having DJD increased with age. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the probability of having hip DJD increased with hip joint laxity as measured by use of DI. This association was breed-specific, indicating that breed-specific information on disease susceptibility should be incorporated when making breeding decisions and when deciding on possible surgical treatment of hip dysplasia.     

Clinical and genetic assessments of hip joint laxity in the Boykin spaniel

Canine hip dysplasia (CHD) is characterized by a malformation of the hip joint that leads to joint laxity and consequential degenerative joint disease. The most widely used method for diagnosis of CHD is the ventrodorsal hip-extended radiologic view, commonly referred to as the Orthopedic Foundation for Animals (OFA) method. The method of the University of Pennsylvania Hip Improvement Program (PennHIP), an alternative technique that is based on hip joint laxity, provides a quantitative assessment, the distraction index (DI), of the likelihood of the development of CHD because of increased laxity in the hip joint. Linear regression analysis showed that, across many breeds of dog, the incidence of CHD, as defined by the OFA, is positively correlated with the mean DI, the determination coefficient (r2) being 26%. We used families of Boykin spaniels (BSs) to determine the level of joint laxity in the breed and to conduct an initial whole-genome screening to identify markers that co-segregate with increased joint laxity. Although there was a positive correlation between the incidence of hip dysplasia and increased joint laxity, we did not find significant linkage in the 28 BSs that underwent genotyping, likely owing to the small size of the pedigree.     

Comparison of measurements of dorsolateral subluxation of the femoral head and maximal passive laxity for evaluation of the coxofemoral joint in dogs

OBJECTIVE: To determine whether dorsolateral subluxation (DLS) of the femoral head reflects osseous conformation of the coxofemoral (hip) joint and represents a property distinct from maximum passive laxity of the hip joint in dogs. ANIMALS: 14 Labrador Retrievers, 16 Greyhounds, 58 Greyhound-Labrador Retriever mixed-breed dogs, and 1 Rottweiler. PROCEDURES: DLS of the femoral head (DLS score) and passive laxity of the hip joint (distraction index) were determined radiographically in 3 groups of dogs: not treated (167 joints of 84 dogs); before and after injecting 2 ml of hyaluronan into 25 hip joints of 13 dogs; and before and after unilateral triple pelvic osteotomy in 5 dogs. Results of the 2 methods were compared for each group. RESULTS: In untreated dogs, the correlation coefficient (r) of DLS score versus distraction index was -0.73 and -0.69 for 84 left and 83 right hip joints, respectively. Mean coefficient of determination (r2) for both hips was 0.5. Mean DLS score did not differ before and after intra-articular injection of hyaluronan into either hip joint, whereas mean distraction index increased significantly after intra-articular injection. Unilateral triple pelvic osteotomy resulted in a significant increase in DLS score, compared with values obtained before surgery. However, distraction index before and after surgery did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE: The DLS test assesses the congruity of the acetabulum and the femoral head in a canine hip joint and thus represents a characteristic distinct from maximum passive laxity. The DLS score and the distraction index evaluate different components of hip joint stability.     

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.     

THE GENETICS AND EARLY PREDICTION OF HIP DYSPLASIA

SUMMARY: Four breeds of dog and crosses amongst these breeds were compared with regard to their hip dysplasia status. Both radiographic hip dysplasia at 15 months and joint laxity at 8 weeks were recorded. The prediction of radiographic hip dysplasia by joint laxity was significantly improved when breed differences were included in the prediction equation. The uses of joint laxity measurements and the genetic control of hip dysplasia are discussed.     

Effects of pubic symphysiodesis in dysplastic puppies

OBJECTIVE--To determine the long-term effects of juvenile pubic symphysiodesis (JPS) in dysplastic puppies. STUDY DESIGN--Prospective, randomized, clinical trial. ANIMALS--Seven dysplastic Chesapeake Bay retrievers and 2 beagle-crosses (BX1 and 2). METHODS--Five puppies had JPS performed with electrocauterization at 12, 16, 20, 22, and 24 weeks of age, respectively. Two puppies served as controls. BX1 and BX2 were used to obtain biopsies of the symphysis. Hips were evaluated for: pelvic development (transverse computerized tomography for acetabular angle [AA] and dorsal acetabular rim angle [DARA]); laxity [hip extended and stress radiography [distraction index (DI)]); Ortolani maneuver with reduction angles; acetabular coverage (Norberg angles); and function (coxofemoral range of motion, hip pain, and gait analysis by force-plate technique at 44 and 137 weeks of age). RESULTS--The pubis fused prematurely in every puppy that was operated on with the JPS technique. Greater acetabular responses were related to younger ages at surgery. The final mean AA in dogs that had JPS was 25 degrees greater than preoperative values; 40% increased over control. The DARA final mean was 10 degrees, 52% less than preoperative values and 46% less than control. The final mean DI in dogs having JPS was 0.28, 47% improved over preoperative values and 58% better than control. Mean pelvic dimensions in dogs that had JPS were 18% less than control. Gait analyses were normal for all dogs at 137 weeks. No urinary or bowel complications occurred. CONCLUSIONS--Significant ventrolateral acetabular rotation, increased hip coverage, diminished hip laxity, normal pain-free gait, and insignificantly reduced pelvic size occurred after JPS. CLINICAL SIGNIFICANCE--Dysplastic hips in young dogs were significantly improved by JPS.     

Evaluation of a radiographic caudolateral curvilinear osteophyte on the femoral neck and its relationship to degenerative joint disease and distraction index in dogs

OBJECTIVE: To determine prevalence of a radiographic caudolateral curvilinear osteophyte (CCO) on the femoral neck in various breeds and age groups of dogs and to evaluate its contemporaneous relationship with degenerative joint disease (DJD) and distraction index (DI). DESIGN: Cross-sectional prevalence study. ANIMALS: 25,968 dogs, including 3,729 German Shepherd Dogs, 4,545 Golden Retrievers, 6,277 Labrador Retrievers, and 1,191 Rottweilers. PROCEDURE: Data from the University of Pennsylvania Hip Improvement Program database were analyzed, including ventrodorsal hip-extended, compression, and distraction radiographs. The CCO and radiographic signs of DJD were considered independent events and were interpreted as either present or absent. Statistical methods were used to evaluate the CCO as a possible risk factor for DJD and assess its association with DI, as measured by use of distraction radiography. RESULTS: When all breeds were pooled, DJD was detected in 8.6% of dogs, and the CCO was detected in 21.6% of dogs. Among dogs with a CCO, 25.1% had radiographic evidence of DJD. Among dogs without a CCO, only 4% had DJD. Dogs with a CCO were 7.9 times as likely to have DJD as were those without a CCO. Additionally, DI, weight, and age were significant risk factors for the CCO. CONCLUSION AND CLINICAL RELEVANCE: Results confirm the contemporaneous association between the CCO and DJD and that passive hip laxity, as measured by use of the DI, is associated with both the CCO and DJD.     

A radiographic stress technique for evaluation of coxofemoral joint laxity in dogs

OBJECTIVE: To develop a radiographic stress technique to quantify hip joint laxity in dogs. STUDY DESIGN: Prospective study on client-owned dogs presented for hip dysplasia screening. ANIMAL POPULATION: 302 nonselected dogs (63 breeds). METHODS: Dogs were sedated and placed in dorsal recumbency. During pelvic radiography, the femoral heads were displaced manually in a craniodorsal direction. On these stress radiographs, the degree of lateral displacement of the femoral heads was assessed in terms of a subluxation index (SI) and compared with the degree of femoral head subluxation and the severity of hip dysplasia found on conventional extended hindlimb radiographs. RESULTS: The degree of subluxation on stress radiographs was significantly greater than on conventional radiographs. Correlation between the severity of canine hip dysplasia (CHD), graded according to conventional techniques, and the degree of subluxation, induced by radiographic stress technique, was positive (r = .57; P<.0001). Two critical SI values were noted. Of the dogs with an SI value of 0.3 or less, 99% were classified as CHD grade normal, borderline, or mildly dysplastic. In dogs with an SI value between 0.3 and 0.5, CHD grading ranged from normal to severely dysplastic. Of the dogs with an SI value greater than 0.5, 95% had dysplastic hip joints. CONCLUSIONS: Hip joint laxity cannot be quantified precisely on standard position radiographs. The proposed stress technique yields significantly higher degrees of femoral head subluxation than the standard position.     

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.     

Computed tomographic evaluation of growth-related changes in the hip joints of young dogs

OBJECTIVE: To evaluate changes in canine hip joint characteristics during growth via computed tomography (CT) and compare CT features of hip joints with and without laxity in young dogs placed in 2 imaging positions. ANIMALS: 21 dogs (42 hip joints). PROCEDURES: From 2 to 12 months after birth, CT examinations of the acetabulum of each hip joint in simulated normal standing and simulated weight-bearing positions were performed monthly for all dogs. Acetabular angle, dorsal acetabular rim angle (DARA), and femoral head diameter (FHd) were analyzed as skeletal variables; the lateral center edge angle (LCEA), dorsolateral subluxation (DLS) score, and center distance (CD) index were analyzed as joint laxity variables. At 12 months, all dogs underwent the Ortolani test to as-sess hip joint laxity. RESULTS: Hip joint laxity was detected in 5 dogs (10 joints) at 12 months of age; from 2 months, the acetabular angle and FHd increased and DARA decreased significantly until 5 months and the LCEA and DLS score increased significantly until 6 months. In nonlax hip joints in both positions, the CD index decreased significantly until 4 months of age and be-came stable thereafter. In lax hip joints, the CD index increased from 4 through 12 months; between 8 and 12 months, these changes were significantly greater in the weight-bearing position than in the standing position. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that CT-detected abnormalities in the DARA and CD index during body weight loading might be useful indicators of hip dysplasia in 2- to 6-month-old 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.     

Passive hip laxity in Estrela Mountain Dog--distraction index, heritability and breeding values

Two hundred and fifteen Estrela Mountain Dogs (EMD) were examined using the PennHIP method between 2002 and 2006. Passive hip laxity (PHL) was estimated calculating the distraction index (DI). Pedigree information was obtained from the Portuguese Kennel Club. The heritability and breeding values were estimated using the linear Animal Model. The DI, using as reference the worst joint of each animal, ranged from 0.15 to 1.12 (0.55 +/- 0.19). The PHL was equal in right and left sides, and was higher in females than in males (P > 0.05 and P <0.01 in the t-test, respectively). The estimated heritability was 0.83 +/- 0.11. The mean breeding values for PHL were stable in EMD born between 1991 and 2003, and showed an improvement in 2004 and 2005. The data confirm high PHL in breeds with high prevalence and severity of canine hip dysplasia. The high heritability indicates that the DI could be reduced in the breed if PHL were used as a selection criterion. The early favourable evolution of DI breeding values could be related with the increase of voluntary radiographic hip screening in the last years, and the subsequent introduction of hip quality as a breeding criterion.     

Determinants of passive hip range of motion in adult Greyhounds

OBJECTIVE: To determine the ranges of normal pelvic limb range of motion in adult Greyhound dogs, and to explore which factors influence hip range of motion in a population bred to meet the specific demands of racing. Design A cross-sectional study design. METHOD: Thirty-two dogs (17 male and 15 female) 13 to 81 months old were randomly selected from a local pool of 160 Greyhounds. Goniometric measurements of hip, stifle and hock range of motion were recorded in triplicate. Signalment information collected included sex, weight and age of each Greyhound. The outcome factors for the study were range of hip flexion and hip extension. The theorised exposures, age, sex, weight, racing history and hock and stifle range of motion, were modelled against the outcome variables by linear regression analysis. RESULTS: Male dogs were significantly heavier (P < 0.001) and older (P < 0.002) than female dogs. Mean hip flexion was 71.75 degrees and mean hip extension 128.10 degrees. The determinants of hip flexion were sex (P = 0.008) and range of stifle flexion (P = 0.002). Race training did not influence the range of hip flexion in the sample. Determinants of hip extension included range of stifle extension (P = 0.015), history of race training (P = 0.004) and hock flexion. The mean hip extension of raced Greyhounds was 134.95 degrees compared with 121.25 degrees for unraced Greyhounds (mean difference -13.70, 95% confidence interval -18.12, -9.29; P < 0.001). CONCLUSIONS: This study has reported isolated pelvic limb joint range of motion in the racing Greyhound. Hip range of motion was affected by stifle range of motion, sex and race training. Dogs that had received race training had greater flexibility, possibly due to training having an active stretching role on muscles, tendons and other structures limiting the hip range of motion.     

Additional kinematic variables to describe differences in the trot between clinically normal dogs and dogs with hip dysplasia

OBJECTIVE: To describe the abnormal gait of dogs with hip dysplasia by use of kinematic gait analysis. ANIMALS: 19 large-breed dogs with moderate to severe clinical and radiographic evidence of hip dysplasia and 10 clinically normal dogs (controls). PROCEDURE: Kinematic and force plate data were collected, and degree of coxofemoral joint abduction-adduction, mediolateral foot movement, distance between hind feet, maximum hind foot elevation, mediolateral pelvic movement, and coxofemoral joint angular acceleration were calculated. Essential Fourier coefficients were determined and used to reconstruct mean angular acceleration curves. Fourier coefficients and foot and pelvic movement data were compared between groups. RESULTS: Dogs with hip dysplasia had a greater degree of coxofemoral joint adduction and range of abduction-adduction and greater lateral pelvic movement, compared with controls. Foot movement variables did not differ significantly between groups. Coxofemoral joint angular acceleration was greater in the middle to end of the stance phase, whereas deceleration was greater in the late stance to early swing phase and middle to end of the swing phase in dogs with hip dysplasia, compared with controls. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in degree of coxofemoral joint abduction-adduction, amount of mediolateral pelvic movement, and coxofemoral joint angular acceleration between clinically normal dogs and dogs with hip dysplasia may indicate a compensation in gait of affected dogs as a result of discomfort or biomechanical effects attributable to hip dysplasia and degenerative joint disease. Information gained from kinematic and kinetic gait analyses may be useful in evaluating treatments for hip dysplasia in dogs.     

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.     

Juvenile pubic symphysiodesis in dysplastic puppies at 15 and 20 weeks of age

OBJECTIVE: To examine the effects of juvenile pubic symphysiodesis (JPS) on hip joint conformation, hip laxity, gait, and the development of degenerative joint disease (DJD) in dysplastic puppies operated at 15 and 20 weeks of age. STUDY DESIGN: Randomized controlled prospective study. ANIMALS-Eighteen female hound puppies with increased hip laxity. METHODS: Puppies were randomized to 1 of 4 treatment groups: JPS at 15 weeks of age (n = 6), sham-operated control at 15 weeks of age (n = 3), JPS at 20 weeks of age (n = 6), and sham-operated control at 20 weeks of age (n = 3). Hip extension with pain scoring, Ortolani palpation, hip reduction angle measurement (HRA), PennHIP radiography (University of Pennsylvania) with measurement of distraction index, Norberg angle measurement, and transverse computed tomographic imaging to measure acetabular angle (AA) and dorsal acetabular rim angle (DARA), were tested preoperatively, and at 1 and 2 years of age. RESULTS: JPS resulted in significant changes in AA, HRA, DARA, and conversion to Ortolani negative status. Larger and more rapid changes in hip conformation were seen when surgery was performed at 15 weeks of age. No significant changes were identified in control dogs. Twenty-five percent of JPS dogs developed DJD whereas 83% of control dogs developed DJD. CONCLUSIONS: JPS resulted in significant improvements in hip joint conformation and hip laxity in dysplastic puppies treated at 15 and 20 weeks of age. Improvements in conformation were significantly greater when surgery was performed at 15 weeks of age. CLINICAL RELEVANCE: JPS appears to be a promising treatment for hip dysplasia and is a safe and technically simple procedure to perform.     

Long-term outcome of juvenile pubic symphysiodesis and triple pelvic osteotomy in dogs with hip dysplasia

OBJECTIVE: To compare long-term outcomes of juvenile pubic symphysiodesis (JPS) and triple pelvic osteotomy (TPO) in dogs with hip dysplasia. DESIGN: Prospective clinical trial. ANIMALS: 18 dogs with hip dysplasia (ie, distraction index > or = 0.5 in at least 1 hip joint and no, mild, or moderate radiographic evidence of degenerative joint disease [DJD]). PROCEDURES: Dogs between 4 and 5.5 months old at enrollment were assigned to undergo JPS, and dogs between 5 and 12 months old were assigned to undergo TPO. All dogs were reexamined at 2 years of age. RESULTS: At 2 years of age, there were no significant differences between groups in regard to lameness scores, angle of extension of the hip joints, distraction index, peak vertical force, acetabular angle, radiographic DJD score, or owner-assigned scores of clinical function. Dorsal acetabular rim angle was significantly higher in dogs that underwent JPS than in dogs that underwent TPO. For dogs that underwent TPO, dorsal acetabular rim angle was significantly decreased and acetabular angle was significantly increased at 2 years of age, compared with values obtained prior to surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that JPS and TPO have similar effects on hip joint conformation in dogs with moderate to severe hip dysplasia but that neither procedure eliminates the hip joint laxity characteristic of hip dysplasia or the progression of degenerative changes.