Distraction Index Research Articles

Radiographic Hip Joint Phenotype of the Pembroke Welsh Corgi

ObjectiveTo investigate the radiographic hip joint phenotype of the Pembroke Welsh Corgi.Study DesignProspective and retrospective cross‐sectional study.AnimalsPembroke Welsh Corgis (n = 399).MethodsVentrodorsal, hip‐extended radiographs were evaluated for subluxation, osteoarthritis (OA), caudolateral curvilinear osteophytes (CCO), and circumferential femoral head osteophytes (CFHO) of PennHIP evaluated Corgis. Joint laxity was measured by distraction index (DI).ResultsAll Corgis had DI > 0.30 (mean, 0.66), 6.8% had OA, 18% had subluxation, 22.3% had CCO, and 74.4% had CFHO. Higher DI increased the odds for subluxation and canine hip dysplasia (CHD) but not for OA, CCO, or CFHO. The presence of CCO increased the odds for OA by 4.6 times (P = .002) and 2.2 times (P = .01) for hip dysplasia. All dogs with OA had CFHO. The presence of CFHO increased the odds for subluxation by 8.7 times (p < .001) and 8.9 times (P < .001) for hip dysplasia. Subluxation increased the odds for OA by 15.4 times (P < .001).ConclusionCorgis had a low frequency of conventional OA despite having hip laxity that has been shown to correlate with hip OA and hip dysplasia in large‐breed dogs. The relationship between CCO and OA was similar to published findings in nonchondrodystrophic large‐breed dogs and the CFHO was significantly associated with subluxation. Both CCO and CFHO are associated with hip dysplasia in this small chondrodystrophic breed.

Chronology of Hip Dysplasia Development in a Cohort of 48 Labrador Retrievers Followed for Life

To determine the chronology of radiographic signs of canine hip dysplasia (CHD), specifically joint laxity and secondary osteoarthritis (OA). Longitudinal cohort study. Paired littermates, 48 Labrador retrievers. Conventional, ventrodorsal, hip-extended (HE) radiographs were evaluated yearly for CHD according to the subjective criteria of the Orthopedic Foundation for Animals (OFA). PennHIP screening was performed at 2 years of age to assess joint laxity by distraction index (DI). Histopathologic evaluation of coxofemoral joints was performed at the dogs' natural end of life. Coxofemoral subluxation, as identified on the HE radiograph occurred by 2 years of age and not thereafter. Accuracy of OFA-criteria scoring was poor: 55% of dogs scored "normal" at 2 years of age became radiographically dysplastic by the end of life (45% negative predictive value, NPV); 92% of the dogs scored as normal at 2 years of age had histopathologic OA of CHD (8% NPV). The DI predicted all 48 dogs to be susceptible to OA of CHD and 98% had radiographic or histopathologic OA by the end of life. OFA-criteria score was profoundly influenced by environmental factors, such as diet restriction and age, reducing its value as a selection criterion. DI measurements were not influenced by dietary treatment suggesting higher trait heritability.

Functional results of lower extremity lengthening by motorized intramedullary nails

The aim of this study was to evaluate the outcome of patients undergoing limb lengthening using motorized intramedullary nails. This study included eleven femora and 4 tibiae from 14 patients (9 male, 5 female; mean age: 26.9 years; range: 14 to 51 years) who underwent limb lengthening using motorized intramedullary femoral nails (Fitbone(®) TAA). Average preoperative limb shortening was 4.9 (range: 2.5 to 7.5) cm. Distraction was initiated on the seventh postoperative day. Serial radiographs and Paley's bone and functional outcome scoring systems were used to evaluate the results. Mean follow-up period was 33.5 (range: 7 to 88) months. Mean distraction index value was 1.2 (range: 0.7 to 2.1) days/mm and mean bone-healing index value was 43.7 (range: 13.8 to 144) days/cm. The average lengthening achieved was 51.7 (range: 25 to 75) mm. The distraction mechanism of the nail did not function properly in two patients, restricted transient knee motion was observed in four patients, and delayed consolidation was observed in four patients. Other complications included valgus deformities and superficial infections surrounding the antenna of the intramedullary nail, as well as femur fractures at the proximal end of the nail. Bone scores were excellent in 11 segments and were good in one segment. Functional scores were excellent for all 12 patients. While usual complications related to the external fixators, such as pin-track infections and mobilization difficulties were not encountered, the development of additional complications such as dysfunction of the distraction mechanism should be monitored with the use of motorized intramedullary nails in limb lengthening.

Palpation and Dorsal Acetabular Rim Radiographic Projection for Early Detection of Canine Hip Dysplasia: A Prospective Study

To determine the value of 2 diagnostic methods: (1) the reduction angle (RA) using the Ortolani maneuver and (2) the dorsal acetabular slope (DAS) from the dorsal acetabular rim (DAR) radiographic projection, to predict osteoarthritis (OA) in dogs with hip dysplasia. Prospective study. Dogs (n = 73). Hip-extended ventrodorsal (VD) radiographic projections, RA, and DAS were evaluated when dogs were 6, 12, and 24 months of age. VD projections were qualitatively scored for OA. RA was determined using the Ortolani maneuver in dorsal recumbency and DAS using the DAR projection. Distraction index (DI) measurements from the compression-distraction radiographic projections (PennHIP method) were also performed at 6 months of age. Statistical analyses were used to establish the range of values of normal and abnormal RA and DAS, to document the temporal variation in RA and DAS, to compare the ability of the different methods to predict coxofemoral OA, to determine the influence of pure passive laxity and of the DAS on the occurrence of an Ortolani sign and on the magnitude of the RA, to establish the relationship between the DAS and subsequent development of passive laxity and coxofemoral OA, and to evaluate the influence of the DAS and RA on the occurrence of coxofemoral OA with severe, moderate, and minimal coxofemoral passive joint laxity, respectively. VD, RA, DAS, and DI methods of coxofemoral joint evaluation correlated significantly with the status of the coxofemoral joints at 2 years of age. The risk of occurrence of coxofemoral OA increased, as the RA, DAS, or DI increased. There was a significant positive linear relationship between RA and DI (P = .015, r(2) = 0.32), RA and DAS (P = .0078, r(2) = 0.38), and DAS and DI (P = .015, r(2) = 0.33). A negative Ortolani sign was at all times significantly predictive of absence of coxofemoral OA at 2 years of age. DAS best predicted coxofemoral OA for DI ≥ 0.7, whereas RA best predicted coxofemoral OA for 0.3 < DI < 0.7; however, RA proved to be the best overall predictor of coxofemoral OA. RA measured at 6 months of age in dorsal recumbency was the best predictor of coxofemoral OA at 2 years of age.

Intellectual Impairment After Treatment for Medulloblastoma and Astrocytoma in Childhood

This study investigated the impact of posterior fossa tumors and their respective treatments, and the impact of clinical and sociodemographic variables, on the intelligence quotient (IQ) of Brazilian children. Twenty patients took part in the study, of which 13 were diagnosed with astrocytoma (average age at evaluation 10.2 y) and 7 with medulloblastoma (average age at evaluation 9.2 y). The first subgroup was submitted exclusively to tumor resection surgery and the second subgroup underwent surgery, chemotherapy (Vincristine, Cisplatine, and Carmustine), and radiotherapy (total dose of 54 Gy). The Wechsler Intelligence Scale for Children (WISCIII) was used. The following statistically significant effects were identified: treatment modality on performance intelligence quotient scores (P=0.02) and processing speed index (PSI) (P=0.01); presence of hydrocephalus at diagnosis on verbal intelligence quotient (P=0.04); tumor localization on perceptual organization index (P=0.03); time interval between diagnosis and neuropsychological evaluation on PSI (P=0.05) and freedom from distraction index (P=0.03); and level of parental formal education on full scale IQ (P=0.02). Exposure to radiotherapy has a significant effect on processing speed and consequently on global intellectual capacity. The impact on intelligence of clinical and sociodemographic variables such as tumor localization, time interval between diagnosis and cognitive evaluation, and parental level of formal education is confirmed in the specific setting of a developing country.

Evaluation of a fibrillin 2 gene haplotype associated with hip dysplasia and incipient osteoarthritis in dogs

To determine whether a mutation in the fibrillin 2 gene (FBN2) is associated with canine hip dysplasia (CHD) and osteoarthritis in dogs. 1,551 dogs. Procedures-Hip conformation was measured radiographically. The FBN2 was sequenced from genomic DNA of 21 Labrador Retrievers and 2 Greyhounds, and a haplotype in intron 30 of FBN2 was sequenced in 90 additional Labrador Retrievers and 143 dogs of 6 other breeds. Steady-state values of FBN2 mRNA and control genes were measured in hip joint tissues of fourteen 8-month-old Labrador Retriever-Greyhound crossbreeds. The Labrador Retrievers homozygous for a 10-bp deletion haplotype in intron 30 of FBN2 had significantly worse CHD as measured via higher distraction index and extended-hip joint radiograph score and a lower Norberg angle and dorsolateral subluxation score. Among 143 dogs of 6 other breeds, those homozygous for the same deletion haplotype also had significantly worse radiographic CHD. Among the 14 crossbred dogs, as the dorsolateral subluxation score decreased, the capsular FBN2 mRNA increased significantly. Those dogs with incipient hip joint osteoarthritis had significantly increased capsular FBN2 mRNA, compared with those dogs without osteoarthritis. Dogs homozygous for the FBN2 deletion haplotype had significantly less FBN2 mRNA in their femoral head articular cartilage. The FBN2 deletion haplotype was associated with CHD. Capsular gene expression of FBN2 was confounded by incipient secondary osteoarthritis in dysplastic hip joints. Genes influencing complex traits in dogs can be identified by genome-wide screening, fine mapping, and candidate gene screening.

Relationships of hip joint volume ratios with degrees of joint laxity and degenerative disease from youth to maturity in a canine population predisposed to hip joint osteoarthritis

To assess relationships of acetabular volume (AV), femoral head volume (FV), and portion of the femoral head within in the acetabulum (FVIA) with each other and with degrees of hip joint laxity and degenerative joint disease from youth to maturity in dogs predisposed to developing hip joint osteoarthritis (OA). 46 mixed-breed half- or full-sibling hound-type dogs. The distraction index (DI), AV, FV, FVIA, and degree of osteoarthritis (OA score) were quantified in 1 hip joint at 16, 32, and 104 weeks of age. Relationships among variables were evaluated within and between ages. Ratios corresponding to OA scores were compared within ages. Differences among 16-week ratios corresponding to 32-week OA scores and among 16- and 32-week ratios corresponding to 104-week OA scores were evaluated. Significant positive relationships existed between FV and AV across ages as well as between FVIA/FV and FVIA/AV and between DI and OA score across and within most ages. Such relationships also existed within these variables across most ages. Negative relationships of DI and OA scores with FVIA/FV and FVIA/AV within and among all ages were significant. Sixteen-week AVs, FVs, and FVIAs were greater and FV/AVs and OA scores were less than 32- and 104-week values. The 32-week FVIA/FV was less than 16- and 104-week values, and the 32-week FVIA/AV was less than the 104-week value. The FVIA/FV and FVIA/AV were lower and the DI was higher with higher OA scores within and among most ages. Structural volumes in lax canine hip joints changed predictably relative to each other during growth, despite degenerative changes. Measures developed in this study may augment current diagnosis and treatment strategies for hip dysplasia in dogs.

Single-stage treatment of complete dislocation of radial head and forearm deformity using distraction osteogenesis in paediatric patients having multiple cartilaginous exostosis

We are reporting the results of single-stage treatment for patients with forearm deformity and radial head luxation due to hereditary multiple exostosis using distraction osteogenesis. Six patients with a mean age of 12 years were treated. Morphological evaluation was made according to Masada (3 of the cases were 2a and 3; 2b). Angular deformities of forearm and wrist were evaluated as described by Fogel (distal radial joint angle was 27°, ulnar variance was 12.8 mm and carpal slip was 71.3%). Mean forearm pronation was 48.4° whilst mean supination was 19.2°. Mean elbow range of motion was 26.6°-103.4° and the mean DASH score was 75. Common surgical procedures were deformity correction, ulnar lengthening and gradual radial head reduction using external fixators. Mean follow-up period was 4.2 years and mean external fixation time was 6 months. Mean amount of ulnar lengthening was 2.9 cm and the distraction index was 14.9 cm/day. Mean radial articular angle was 14.3°, ulnar variance 2.3 mm, carpal slip 55%, forearm pronation 65.9° and supination was 55°. Mean elbow range of motion was 15.8°-119.2°. In the last follow-up, the mean value of DASH score was 8.1. Major and minor complications were seen during the follow ups. Single-stage deformity correction, ulnar lengthening and radial head reduction technique that we have used provide satisfactory functional and cosmetic results. Early surgical correction may lead to even better results.

Evaluation of the relationship between Orthopedic Foundation for Animals' hip joint scores and PennHIP distraction index values in dogs

To compare 2 screening methods for detecting evidence of hip dysplasia (Orthopedic Foundation for Animals [OFA] and PennHIP) in dogs. Diagnostic test evaluation study. Animals-439 dogs >or= 24 months of age that received routine hip joint screening from June 1987 through July 2008. Dogs were sedated, and PennHIP radiography was performed (hip joint- extended [HE], compression, and distraction radiographic views). The HE radiographic view was submitted for OFA evaluation. A copy of the HE radiographic view plus the compression and distraction radiographic views were submitted for routine PennHIP evaluation, including quantification of hip joint laxity via the distraction index (DI). 14% (60/439) of dogs had hip joints scored as excellent by OFA standards; however, 52% (31/60) of those had a DI >or= 0.30 (range, 0.14 to 0.61). Eighty-two percent of (183/223) dogs with OFA-rated good hip joints had a DI >or= 0.30 (range, 0.10 to 0.77), and 94% (79/84) of dogs with OFA-rated fair hip joints had a DI >or= 0.30 (range, 0.14 to 0.77). Of all dogs with fair to excellent hip joints by OFA standards, 80% (293/367) had a DI >or= 0.30. All dogs with OFA-rated borderline hip joints or mild, moderate, or severe hip dysplasia had a DI >or= 0.30 (range, 0.30 to 0.83). Dogs judged as phenotypically normal by the OFA harbored clinically important passive hip joint laxity as determined via distraction radiography. Results suggested that OFA scoring of HE radiographs underestimated susceptibility to osteoarthritis in dogs, which may impede progress in reducing or eliminating hip dysplasia through breeding.

Canine hip dysplasia treated by juvenile pubic symphysiodesis

To determine the clinical effects of juvenile pubic symphysiodesis (JPS) treatment in hip dysplasia-prone puppies with comparison to similar untreated control puppies. Controlled clinical case study. Thirty-nine dysplastic puppies, of which six were part of the control group, with a positive Ortolani or hip distraction index (DI)≥0.40. The following eight clinical tests were evaluated preoperatively, and at one and two years postoperatively: Ortolani, hip reduction angle (HRA), gait evaluation, osteoarthritis, hip pain, and three Norberg angles (angle-extended mode [N-OFA], angle-compression mode [N-COM], and angle-distracted mode [N-DIS]). Juvenile pubic fusion (JPS) was performed by unipolar electro-cautery at 12 to 24 weeks of age; the control puppies received a sham operation. For the JPS puppies, the mean osteoarthritis level did not significantly increase (11%). There was a 74% reversal of preoperative positive Ortolani signs. Hip reduction angle, DI and N-DIS also improved significantly. Only N-DIS fully detected Norberg angle laxity. Within the control group, osteoarthritis increased significantly (55%) with no improvement in Ortolani incidence, N-OFA or N-COM angles. A decrease in HRA and DI was associated with increased osteoarthritis levels. Signs of hip pain increased by 33%, which was not significant. Dogs with initial severe hip laxity (DI≥0.70) experienced progressive osteoarthritis. In JPS dogs with preoperative mild to moderate hip laxity (DI = 0.40-0.69), insignificant osteoarthritis occurred at two years. Juvenile pubic symphysiodesis surgery also improved other clinical criteria (Ortolani, HRA, hip pain, N-DIS). Osteoarthritis was generally not prevented by JPS in dogs with initial severely lax hips (DI≥0.70). Juvenile pubic symphysiodesis surgery at 12 to 24 weeks of age was an effective and safe pre-emptive bilateral treatment for mild to moderate hip dysplasia.

Canine hip dysplasia treated by juvenile pubic symphysiodesis

To measure one and two year effects of juvenile pubic symphysiodesis (JPS) in puppies defined as 'at-risk' for canine hip dysplasia (CHD) using the following objective hip conformation criteria: Acetabular angle (AA), dorsal acetabular rim angle (DARA) and hip laxity (PennHIP© distraction index (DI). Controlled clinical case study. Thirty-nine dysplastic puppies (six controls). The dogs were anaesthetised and acetabular angle, DARA, and DI values were obtained by computed tomography and radiography preoperatively. Electro-cautery fusion of the pubic symphysis was performed between 12 - 24 weeks of age. The imaging was repeated at one and two years of age. Significant hip improvements were seen at the two-year follow-up appointments for: AA (JPS dogs 31% increase, control 3%), DARA (JPS 38% decrease, control 15%) and DI (JPS 41% decrease in laxity, controls 20%) for all postoperative versus preoperative values. Pubic fusion occurred with minor morbidity. Juvenile pubic symphysiodesis resulted in significant improvements in hip conformation (AA and DARA), especially in mild to moderately lax hips (DI = 0.40-0.69). Most dogs with DI≥0.70 increased in osteoarthritis grade by two years of age. Juvenile pubic symphysiodesis surgery at 12-24 weeks of age significantly improved hip conformation and decreased laxity in at-risk CHD dogs. Early-age (12 to 16 week) recognition of hip laxity offered greater JPS benefits than surgery performed at 19- to 24-weeks-old. Dogs with severe laxity (DI≥0.70) continued to increase in osteoarthritis. An early (12-16 weeks) positive laxity test (Ortolani) should alert one to obtain objective laxity determinations (PennHIP© DI).

Ausgleich posttraumatischer Beinverkürzungen mit einem motorisierten intramedullären Nagel

Fractures in childhood may result in a significant leg length discrepancy (LLD). The common correction method of LLD and deformities is callotasis with external fixation. This is often associated with pain, pin site infection, muscle tethering and reduced range of movement (ROM). Between 2006 and 2008 a total of 11 cases of posttraumatic LLD (range 2.4-4.3cm) were treated with a fully implanted motorized lengthening device (Fitbone®). Hospitalization time, leg equalization, rehabilitation time and complications compared to external fixation were recorded. Leg lengthening was successfully performed in all cases, in five combined with angular and/or rotatory corrections. The mean distraction index was 1.03mm/day (range 0.6-1.2mm/day) and the mean consolidation index was 40 days/cm (range 25.2-50.9 days/cm). The average hospital stay was 9.8days (range 8-20 days). Bone or soft tissue infections were not observed, nor were the complications commonly associated with external fixation. Functional results were excellent as the preoperative knee ROM was regained in all cases and with improved ROM in three cases. The Fitbone® nail is a valuable alternative to conventional methods which reduces complications commonly associated with external fixation.

An electrophysiological study of response conflict processing across the lifespan: Assessing the roles of conflict monitoring, cue utilization, response anticipation, and response suppression

We recorded Electroencephalograms (EEGs) during a cued Continuous Performance Task (CPT) to investigate lifespan differences in the efficiency of response conflict processing under conditions that put high demands on the ability to suppress a prepotent response. Previous evidence indicates that children and adolescents commit more errors under such conditions than younger adults, whereas older adults are disproportionately slow in responding. We measured event-related potentials (ERPs) in a sample of 45 children, 44 adolescents, 46 younger adults, and 47 older adults to investigate response conflict monitoring (Nogo-N2), cue utilization (Cue-P3), response anticipation (contingent negative variation, CNV), and response suppression (Nogo-P3). In comparison to adolescents and adults, children showed larger ERPs associated with cue utilization. At the same time, children committed more errors and their ERPs reflecting response anticipation and response suppression were smaller and uncorrelated. In contrast, older adults showed ERP indices of attentional distraction (P3a elicited by the infrequent Non-Cue stimuli), reduced conflict monitoring signals (Nogo-N2), and took more time to respond than the other age groups. The present findings reveal marked lifespan differences in processes related to response conflict monitoring. In middle childhood, the readiness to utilize cues for guiding actions is not yet fully matched by the ability to suppress prepotent responses, leading to a relatively large number of commission errors. In older adults, higher indices of attentional distraction as well as lower conflict monitoring signals were observed. This might reflect a dampened build-up of response tendencies, thereby leading to slower responding and relatively low error rates.

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

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. 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. 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. 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.

Cingulate gyrus morphology in children and adolescents with fetal alcohol spectrum disorders

Alcohol consumption during pregnancy can lead to a variety of cognitive and other birth defects, collectively termed fetal alcohol spectrum disorders (FASD), and including the Fetal Alcohol Syndrome (FAS). This study examined the impact of gestational alcohol exposure on the morphology of the cingulate gyrus, given this region's role in cognitive control, attention, and emotional regulation, all of which are affected in children with FASD. Thirty-one youth (ages 8–16) with histories of heavy prenatal alcohol exposure ( n = 21) and demographically matched comparison subjects ( n = 10) underwent structural magnetic resonance imaging. The cingulate gyrus was manually delineated, and parcellated volumes of grey and white matter were compared across groups. Alcohol-exposed individuals had significantly smaller raw cingulate grey matter, white matter, and tissue volumes compared with controls. After adjustment for respective cranial tissue constituents, only white matter volumes remained significantly reduced, and this held regardless of whether or not the child qualified for a diagnosis of FAS. A correlation between posterior cingulate grey matter volume and the WISC-III Freedom from Distractibility Index was also observed in alcohol-exposed children. These data suggest that cingulate white matter is compromised beyond global white matter hypoplasia in alcohol-exposed individuals, regardless of FAS diagnosis. The observed volumetric reductions in the cingulate gyrus may contribute to the disruptive and emotionally dysregulated behavioral profile commonly observed in this population.

An assessment of the agreement between the New Zealand Veterinary Association Hip Dysplasia Scoring System and the PennHIP distraction index in German Shepherd dogs

AIM: To determine the level of agreement between the New Zealand Veterinary Association (NZVA) Hip Dysplasia Scoring System and the University of Pennsylvania Hip Improvement Program (PennHIP) Distraction Index in German Shepherd dogs, and whether using the NZVA subtotal score or its components affected the level of agreement. METHODS: A prospective study was performed using 47 German Shepherd police dogs undergoing breeding evaluation. All dogs were scored using the NZVA system and the PennHIP index. The relationships between the individual hip-distraction index scores and the scores from the NZVA system, i.e. the total score, the subtotal score, and the scores for the categories making up the subtotal score, were analysed using correlation, followed by univariate ANOVA for the subtotal categories alone. The scores from the NZVA system and the distraction index were then dichotomised into either low or high risk of canine hip dysplasia (CHD). A sign test was then used to determine whether three NZVA thresholds identified the same proportion of ‘at-risk’ dogs as the distraction-index threshold. Where this was the case, the Kappa value was calculated to identify the degree of agreement between the NZVA measures and the distraction index. RESULTS: The left-hip distraction index was significantly correlated to both left-subtotal and left-total NZVA score, however for right-hip scores there was no such correlation. The individual categories of the subtotal NZVA score were not significantly associated with the distraction index except for the subluxation score of the left hip. The proportion of dogs identified as being ‘at risk’ for CHD identified using a distraction-index threshold of 0.3 was similar to that identified by an NZVA total or subtotal score of >2 (44/47 cf. 45/47, respectively). However, none of the dogs identified as low risk using the distraction index was identified as low risk by either of the NZVA scores. This poor agreement (Kappa value <0) was not improved by using a threshold of >1 in any of the categories used to calculate the NZVA score. The agreement between the two scores was improved by using different thresholds; distraction index >0.5 and an NZVA total score of >9. These thresholds identified a much lower proportion of ‘at-risk’ dogs (5/47 and 10/47, respectively) than the standard thresholds. The Kappa values using the thresholds of 0.5 for the distraction-index and ≥9 for the NZVA scores were moderate for subtotal (0.55; 95% CI=0.16–0.94) and low for total (0.31; 95% CI=−0.02 to 0.63) score. CONCLUSIONS: The low level of agreement between the NZVA total scores and the PennHIP distraction index, particularly when the standard interpretations were used, is of concern as assessing dogs by each method gave disparate results. There was evidence from this study that using the subtotal score moderately improved the level of agreement with distraction index, but only at the higher thresholds. CLINICAL RELEVANCE: The low level of agreement between NZVA and PennHIP results in the same dog precludes them being used interchangeably to guide breeding decisions. The higher heritability of distraction-index measurement in previous studies suggests that it is a better selection tool for breeding dogs when CHD is present within a population. The advantage of a hip-extended ventrodorsal view is its low cost and widespread availability but comparisons between individuals may not be accurate due to the poor sensitivity and the presence of false negatives.

Evaluation of quantitative trait loci for hip dysplasia in Labrador Retrievers

To identify the quantitative trait loci (QTL) that contribute to hip dysplasia in dogs. 192 Labrador Retrievers. Hip dysplasia was measured by use of the Norberg angle (NA), dorsolateral subluxation (DLS) score, and distraction index (DI). Genome-wide screening was conducted by use of 276 unique microsatellites. Linkage analysis was performed with a variance-based linear model. Logarithm of the odds (LOD) scores were reported when values were > 2.0. Canis familiaris autosomes (CFAs) 01, 02, 10, 20, 22, and 32 harbored significant QTL at LOD scores > 2.0. Among the 6 QTL, the QTL on CFA02 had not been reported to harbor QTL for hip dysplasia. The highest LOD score of 3.32 on CFA20 contributed to the second principal component of the DLS score and NA of the right hip joint. The QTL that was mapped on CFA01 (LOD score of 3.13 at 55 centimorgans) was located on the same chromosome reported to harbor a QTL for hip dysplasia in Portuguese Water Dogs and German Shepherd Dogs. In this study, CFAs 10, 20, 22, and 32 harbored QTL for hip dysplasia that have been identified in a Labrador Retriever-Greyhound pedigree and in German Shepherd Dogs. Multiple QTL were clearly involved with hip dysplasia. Identification of these QTL will enable fine-resolution mapping and subsequent assessment of candidate genes within the refined intervals to enable researchers to develop genetic screening tests and preventative and novel therapeutic regimens.

Shortening and secondary relengthening for chronically infected tibial pseudarthroses with poor soft tissues

BackgroundThe treatment of chronically infected tibial pseudarthroses with poor soft tissues ends with amputation on many occasions. Aggressive débridement of bone and soft tissue and reconstruction of the extremity, performed as a limb salvage procedure, is an alternative treatment option to amputation. MethodsOur patients had a mean age of 42 years. According to the Paley classification, one of the patients had A2 pseudoarthrosis, four had B2, and three had B3. One had localized infection, whereas the other seven had diffuse infection, according to the Cierny-Mader system. The mean duration of the infection was 10.75 years, and the mean number of previous operations was 5.13. The mean shortness was 2.4 cm, and the mean bone defect was 1 cm. ResultsThe mean primary shortening was 8.6 cm, the mean duration of the fixator stay was 9.6 months, and the mean distraction index was 39.1 days/cm. The mean duration of follow-up was 25 months. The bone results were excellent in four cases, good in two, and fair in the other two. The functional results were excellent in one patient, good in six, and fair in one. A total of 11 minor and 3 major complications were seen during the treatment, and one case resulted in amputation.Coclusions.Despite the high rate of complications, our treatment method enabled limb salvage for patients who had previously been candidates for amputation. With this treatment, there is less need for a second operation, and an additional operation is not necessary for soft tissue coverage.

Effects of osteoarthritis on radiographic measures of laxity and congruence in hip joints of Labrador Retrievers

OBJECTIVE- To determine effects of hip joint osteoarthritis on radiographic measures of hip joint laxity and congruence. DESIGN- Longitudinal study. ANIMALS- 40 Labrador Retrievers. PROCEDURES- Dogs were assigned to 2 groups based on radiographic evidence of osteoarthritis. Dogs in the osteoarthritis group were free of osteoarthritis at initial radiographic evaluation (t(1)) and developed osteoarthritis by a subsequent radiographic evaluation (t(2)). Dogs in the nonosteoarthritis group had no radiographic osteoarthritis at either evaluation. Hip joint laxity was quantified by use of the distraction index (DI) from a distraction radiographic view and use of the Norberg angle (NA) from a ventrodorsal hip-extended radiographic view. The compression index (CI) from a compression radiographic view was used as a measure of joint congruence (concentricity). RESULTS- Hip joint laxity (NA or DI) did not change over time in the nonosteoarthritis group. Mean hip joint laxity (NA and DI) for the osteoarthritis group was greater at t(1) than for the nonosteoarthritis group. With the onset of osteoarthritis, mean NA decreased significantly and mean CI increased significantly, but mean DI remained unchanged. CONCLUSIONS AND CLINICAL RELEVANCE- No radiographic evidence for compensatory hip joint tightening associated with osteoarthritis was detected. Hip-extended radiography revealed that hip joints got looser with osteoarthritis and NA decreased. Hip joint laxity (DI) on distraction radiographs was unchanged by the onset of osteoarthritis and remained constant in the osteoarthritis and nonosteoarthritis groups at both evaluations. However, the CI increased with osteoarthritis, as reflected in nonzero indices (incongruence). The CI may be a valid marker for early hip joint osteoarthritis.

Neuropsychological differences between attention deficit hyperactivity disorder and control children and adolescents referred for academic impairment

To compare the performances of children and adolescents with attention deficit hyperactivity disorder with a group of control comparison subjects, both taken from a large clinical sample, using some of the most widely employed attention-based Brazilian tests. The performances of 186 children and adolescents with attention deficit hyperactivity disorder were compared to that of 80 control individuals based on attention and working memory scores. Both groups had been referred due to academic impairment. All individuals were submitted to the TAVIS-3 sustained, shifted and focused attention tests, as well as to the working memory tests that make up the WISC-III Freedom from Distractibility Index (Digit Span and Arithmetic). The control group was slightly older than the attention deficit hyperactivity disorder group (p = 0.07); IQ and schooling did not differ between groups (p = 0.34 and p = 0.38, respectively). While performing a test requiring sustained attention for a longer period of time, the attention deficit hyperactivity disorder group showed a significantly higher number of commission errors compared to the controls, thus presenting sustained attention deficits (p = 0.003); when the influence of IQ, age and schooling was reduced, the attention deficit hyperactivity disorder group also made more omission errors during a sustained attention task in comparison to the control group, thus achieving a borderline significance level (p = 0.08); the attention deficit hyperactivity disorder group also performed worse in Digit Span forward and backward (p = 0.013 and p = 0.01, respectively) and in Arithmetic (p = 0.008). Other scores did not achieve significance. Our findings suggest that some of the most commonly used Brazilian attention-based tests - especially the sustained attention and working memory tests - may be useful to help distinguish subjects with attention deficit hyperactivity disorder from control subjects.