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Diagnostic and genetic aspects of patellar luxation in small and miniature breed dogs in Austria

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Abstract

Introduction: The aim of the study was to investigate a diagnostic protocol for patellar luxation (PL) in respect to its usability as a screening method in the framework of breeding programs. Further, the influence of breed, age, body mass, gender and neutering on the prevalence of PL has been investigated. Methods: In a period of 8 years (1996-2004) 432 small and miniature-breed dogs have been examined for patellar luxation. In order to achieve the diagnostic efficiency required for genetic screenings performed in the framework of breeding programs, this examination was based on the concept of a standardized examination protocol that included clinically examination with inspection as well as palpation. The diagnostic criteria were lameness, palpation and evaluation of patellar tracking in standing and recumbent position of the dog with special focus on the presence of any patellofemoral instability. A further diagnostic criterion was the deviation of the tibial tuberosity and any perceivable crepitation of the knee joint during all manipulations performed. The findings of patellar luxation were valuated according to PUTNAM's (1968) graduation. X-rays have not been performed. To find out whether the investigated diagnostic criteria fulfil the demands on consistency and validity needed for screening, diagnostic rank correlation coefficients between the single diagnostic criteria and the final PL-finding have been calculated. The influence of breed, age, body mass, gender and neutering on the occurrence of PL was investigated by calculating odds ratios using a multifactorial logistic regression model. The significance testing of the resulting odds ratios was performed by calculating the corresponding 95 % confidence intervall. Results: In 61.6 % of the examined dogs we found patellar luxation, but only in 15.5 % (right knee) and 12.8 % (left knee) a permanent lameness could be observed; in 3.5 % (right kee) and 4.6 % (left knee) there was an intermittent lameness. Therefore nearly 40 % of the animals with patellar luxation were clinically normal and would not have been detected as carriers of patellar luxation without screening diagnostic. The investigated diagnostic criteria showed significant correlation among each other and with the final PL-finding and therefore proved to be consistent and meaningful with regard to PL- investigation. The parameters "luxation in standing" and "luxation in recumbent position" showed the highest rank-correlation to the final findings. Thus it appears that, in general, this examination protocol is suitable for PL-screenings. The investigation of the influence of the parameters "body mass", "age", "gender" and "neutering" on the occurrence of PL showed that except "gender" all attributes are associated with occurrence of PL. An increase in body mass of 1 kg decreases the odds of suffering from PL to the 0.8fold (p < 0.05), an increase of age of one year increases the odds of suffering from PL to the 1.1fold (p = 0.051). Neutered dogs showed a 3.10fold odds for suffering from PL (p < 0.05). To detect breed predispositions for patellar luxation odds ratios were calculated for each breed that was represented in the study by more than 10 animals, including Jack Russell Terrier, Mops, Papillon, Pekingese, Shih Tzu, Tibet Terrier, West Highland White Terrier, Poodle, Yorkshire Terrier, Malteser and Chihuahua. 2 breeds showed a significantly different outcome with regard to increase of suffering from PL. The Jack Russell Terrier had an odds ratio of 0.31 with corresponding 95 % confidence intervals 0.14 -0.67 and therefore showed a reduced chance of PL compared with all other breeds. On the other hand the Poodles (including the miniature- and toy-variants) with an odds ratio of 5.62 with corresponding 95 % confidence intervals 1.93-16.41 showed a higher chance of PL compared with all other breeds. This result gives some evidence on a genetic background of PL. Nevertheless the genetic basis of PL should be investigated more accurately by family analyses and heritability studies. Conclusions: Referring to the consistency and validity of the diagnostic criteria the diagnostic protocol used in this study seems to be suitable as screening method for PL. As 2 of the investigated breeds showed a significantly higher or lower chance for suffering from PL a genetic background of PL can be postulated. Based on the results of this study it would be highly recommended for breeding associations to introduce screening programs for patellar luxation in small and miniature breed dogs as described in this study in combination with a redefinition of breeding goals aimed at the extreme miniaturization of the affected dog breeds.

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... Neuter status was also a significant risk factor in the current study, with neutered dogs having 2.4 times the odds of patellar luxation compared with entire animals. A study of small and miniature breed dogs in Austria similarly reported that neutered dogs had 3.1 times the odds of being affected with patellar luxation [49]. Although, the pathogenesis behind these sex and neuter associations is currently unclear, hormonal influences on growth rates and musculoskeletal development are possible. ...
... Breeds that were particularly affected included the Pomeranian (6.4 % prevalence of diagnosis), Yorkshire Terrier (5.3 %) and Chihuahua (4.8 %), consistent with previous publications reporting increased susceptibility in small breed dogs [4,10,21,25,27,28]. A report on a prospective screening programme for patellar luxation in small and miniature breed dogs in Austria similarly concluded that miniaturisation may play a role in the development of patellar luxation [49]. ...
... In terms of clinical management, 39 % of dogs diagnosed with patellar luxation in the current study received some medical treatment while the remainder did not receive any direct therapy for the condition during the study period. Although patellar luxation may initially cause minimal discomfort [49], medical treatment can be required later to manage secondary osteoarthritis [6] and the disorder has also been associated with increased risk of cranial cruciate ligament disease [56]. Surgical stabilisation was performed in just 13 % of the primarycare patellar luxation cases in the current study compared with 83 % of referred patellar luxation cases that are reported to receive surgical intervention [10]. ...
Article
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Background Canine patellar luxation is one of the most common orthopaedic disorders of dogs and is a potential welfare concern because it can lead to lameness, osteoarthritis and pain. However, there are limited epidemiological data on the disorder relating to the general population of dogs in England. This study aimed to investigate the VetCompass Programme database of dogs attending primary-care veterinary practices in England to report on the prevalence, risk factors and clinical management of diagnosed patellar luxation cases. Results The study included all dogs with at least one electronic patient record in the VetCompass database from September 1st, 2009 to August 31st, 2014. Candidate patellar luxation cases were identified using free-text word searching of the clinical notes and VeNom diagnosis term fields. Univariable and multivariable binary logistic regression modelling was used for risk factor analysis. The overall dataset comprised 210,824 dogs attending 119 clinics in England. The prevalence of patellar luxation diagnosis in dogs was 1.30 % (95 % confidence interval (CI) 1.21–1.39). Of the 751 incident cases, 293 (39.0 %) received medical management, 99 (13.2 %) received surgical intervention and 28 (3.7 %) were referred for further management. Multivariable modelling documented 11 breeds with increased odds of patellar luxation compared with crossbred dogs, including the Pomeranian (odds ratio [OR]: 6.5, 95 % CI 4.0–10.7, P < 0.001), Chihuahua (OR: 5.9, 95 % CI 4.4–7.9, P < 0.001), Yorkshire Terrier (OR: 5.5, 95 % CI 4.3–7.1, P < 0.001) and French Bulldog (OR: 5.4, 95 % CI 3.1–9.3, P < 0.001). Dogs with bodyweight below their mean for breed and sex had a 1.4 times odds of diagnosis (95 % CI 1.2–1.6, P < 0.001). Dogs aged ≥ 12.0 years showed 0.4 times the odds (95 % CI 0.3–0.5, P < 0.001) compared with dogs aged < 3.0 years. Females had 1.3 times the odds (95 % CI 1.1–1.5, P < 0.001), neutered dogs had 2.4 times the odds (95 % CI 1.8–3.2, P < 0.001) and insured dogs had 1.9 times the odds (95 % CI 1.6–2.3, P < 0.001). Conclusions Patellar luxation warrants inclusion as a welfare priority in dogs and control strategies that include this disorder should be considered as worthwhile breeding goals, especially in predisposed breeds.
... Based on our results, a sample size of 416 paired examinations would be necessary to show significance. While additional oestrus cycles might have changed our results, other physiological/anatomical aetiologies should probably be considered responsible for the change in MPL grade previously seen over time (Nilsson et al., 2018;Vidoni et al., 2005). While a retrospective study of dogs with occult grade 2/4 medial patellar luxation found that 50% of cases worsened to the point of requiring surgery within approximately 4 years (Hamilton et al., 2020), we are not aware of longitudinal studies looking at the possible rate of progression in grade of untreated MPL over time or development in dogs predisposed but graded free of patellar luxation. ...
... Evaluation in both the standing and recumbent patient is often recommended (Koch et al., 1998;L'Eplattenier and Montavon, 2002), as stability can be affected by muscle tone. In the authors' experience, some dogs become stressed when held in recumbency, making this position inconsistent for patellar diagnosis, and a previous study found that luxation was more often diagnosed in the standing dog (Vidoni et al., 2005). The grading system used did not account for so-called "loose" patellae, which do not warrant a grade 1, but are more mobile than normal (van Grevenhof et al., 2016). ...
Article
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Study aims were to evaluate if medial patellar luxation clinical grades changed with oestrus status, and to determine interobserver agreement for different classification methods for grading patellar luxation. Intact female dogs were recruited for grading by 3 independent observers on 2 occasions (pro-oestrus/oestrus and dioestrus/anoestrus) using a published grading system. Observers were blinded to oestrus status. Oestrus status was confirmed by vaginal cytology. Observer agreement was determined using Fleiss' multirater kappa on the original grading scores, simplification to the Norwegian Kennel Club system, and further simplification to a binary suitable/not-suitable for breeding system. The exact McNemar's test was used to assess the effect of oestrus on classification. Of 70 dogs recruited, 53 underwent paired observations. Interobserver agreement was considered moderate to very good for the study sub-groups, with overall kappa values of 0.68 (95% CI 0.63-0.72), 0.79 (0.73-0.84) and 0.92 (0.85-0.99), and percentage agreements of 65%, 81% and 94%, for the original, simplified and binary classifications. Oestrus status did not have a significant effect on classification of breeding suitability. Clinicians and owners should not be concerned about the timing of patellar luxation grading in relation to oestrus. Experienced observers show good or very good agreement using the Norwegian Kennel Club and binary categorisations.
... The patella either deviates in dorsal, lateral, medial, or rarely ventral direction (Burnei et al., 2020). The cause of PL in different species has been suggested to be a multi-causal type of disorders; congenital in immature animals and acquired in adults due to traumatic incidences (Fowler, 1998;Van Hoogmoed et al., 1998;Shettko and Trostle, 2000;Vidoni et al., 2006;Abuja et al., 2014;Di Dona et al., 2018). The patella is a large sesamoid bone embedded into the inserted tendon of the quadriceps muscle of the thigh (Frandson et al., 2009). ...
... This practice may have contributed to the emergence of such musculoskeletal disorders. Cases with congenital luxation with a suspected hereditary component have been reported and are thought to be inherited in different animal breeds (Kaneps et al., 1989;Vidoni et al., 2006;Gangwar et al., 2014;O'Neill et al., 2016). In addition, PL was suggested to result from a transmission of recessive genes in Shetland ponies and sheepdogs (Hermans et al., 1987;Solanti et al., 2002). ...
Article
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Abstract Background: Patellar luxation (PL) is a common orthopedic affection among farm and pet animals with mostly congenital (environmental and/or genetic) background. Aim: We report here the first observation of lateral PL in Hejazi goats bred in Libya. Methods: Five Hejazi goats aged between four months to two years with severe hind limb lameness were admitted to Al-Sorouh veterinary clinic in Tripoli during the period from 2016 to 2018. The goats were thoroughly examined clinically and radiographically. Two goats were surgically treated, and the other three cases were not because of either the cost limitation or expected poor prognosis. The surgical intervention involved femoral trochlear sulcoplasty, medial joint capsule imbrication, and tibial tuberosity transposition. Results: The clinical examination showed grade III to IV lateral PL. Radiologically, there were unilateral or bilateral, ventrocaudal and dorsal PLs. Two cases were referred to surgical correction. One case almost restored the normal movement of stifle joint together with a good general status one-year post-surgery. However, the surgical treatment was not effective in correcting the luxated patella in the second case. Conclusion: Lateral PL is common among orthopedic affections in Hejazi goats in Libya, and its surgical treatment provided a quite convenient approach. An association between inbreeding and the PL was suggested in those cases. Keywords: Clinical and radiological findings, Hejazi goat breed, Inbreeding, Patellar luxation, Surgical treatment.
... Surgery is aimed at realigning and stabilising the extensor mechanism of the stifle joint and at re-establishing normal limb function. The patella can luxate medially, laterally or both in a medial and lateral direction (Vidoni et al. 2006). The term bidirectional PL (BPL) is used when the patella luxates both medially and laterally. ...
... The prevalence of BPL is also reported in other small and miniature breed dogs (Vidoni et al. 2006). It was unusual that two of the Pomeranians with BPL were older than 6 years at the time of referral, because clinical signs of UMPL usually develop at an earlier age (Wangdee et al. 2013). ...
Article
Seven Pomeranians with bidirectional patellar luxation (BPL) were prospectively studied regarding aetiology and results of a new surgical technique. Radiographic evaluation of the ratio between patellar ligament length and patellar bone length revealed no differences between Pomeranians with bidirectional patellar luxation and healthy stifle joints. Functional rather than anatomic patella alta might be associated with bidirectional patellar luxation in Pomeranians. The surgical outcome of extended proximal trochleoplasty was good-to-excellent in 87·5% of the stifles and all dogs achieved functional recovery. There was only minimal radiographic progression of osteophyte formation at 48 weeks after surgery. To the authors’ knowledge, this is the first report on bidirectional patellar luxation in small breed dogs and its successful surgical treatment.
... 28 Patellar luxation is unrelated to age at gonadectomy, but gonadectomized dogs may be at an increased risk for patellar luxation, compared with the risk for sexually intact dogs. 4,162 A study 162 conducted to evaluate diagnostic and genetic aspects of patellar luxation found that body weight, age, and neuter status were associated with patellar luxation. Because the gonadectomized dogs of that study 162 were significantly older than the sexually intact dogs, the author stated that the role (if any) of gonadectomy in the mechanisms leading to patellar luxation could not be deduced from the data. ...
... Age at gonadectomy of the dogs was also unknown. 162 Continued research into these potential associations appears to be warranted. However, analysis of the literature currently does not justify considering these diseases when making clinical decisions about if or when to spay or neuter a canine patient. ...
... In the present study, 75% of dogs with medial patellar luxation belonged to small and medium-sized breeds. This was in agreement with reports of an inverse relationship between body weight and the probability of developing patellar luxation (20,22). The distribution of lateral patellar luxation was 20% in small breeds, 24% in medium-sized breeds, and 56% in large breeds. ...
... It is not surprising that patellar luxation manifests relatively early in life in dogs predisposed to this condition. However, another study reported a positive correlation between age and the occurrence of patellar luxation, and that the prevalence of patellar luxation increased 1.1-fold with every additional year (22). ...
Article
Objective: To determine the prevalence of patellar luxation in dogs in Italy and its relation to signalment, the frequency and the type of postoperative complications and the outcome of treatment, and to compare the findings with those of other studies. Materials and methods: The medical records from four referral clinics were searched for dogs with orthopaedic disorders referred from 2009 to 2014. From these data, the records of dogs with patellar luxation were identified, and the signalment, age and body weight, grade, side and direction of patellar luxation, treatment, postoperative complications, and outcome were retrieved. Univariate and multivariate statistical analyses were used to evaluate the data. Results: Of 8,694 canine orthopaedic cases, fractures not included, patellar luxation was diagnosed in 559 dogs (801 stifles). Mixed breed dogs were most commonly affected (18%), 85% of the luxations were medial, and 52% of the dogs were female. Of the 559 dogs examined, 400 (574 stifles) met the inclusion criteria for treatment evaluation. Minor complications occurred in five percent of the dogs, and major complications in 16%, including recurrence of patellar luxation in seven percent of the dogs. The outcome was good in 88% of stifles, fair in two percent, and poor in 10%. Clinical significance: Although patellar luxation was more common in small breed dogs, it also was diagnosed in a significant number of large breed dogs, which included medial patellar luxation in 73% and lateral patellar luxation in 27% of stifles. Body weight and grade of luxation were the only variables statistically correlated with surgical complications.
... LH binds to receptors on many tissues throughout the body; this reaction stimulates a number of cellular processes including cell division and nitric oxide release. In addition, gonadectomized dogs have increased risks of a number of orthopedic diseases, including cranial cruciate-ligament insufficiency, hip dysplasia and patellar luxation (44)(45)(46)(57)(58)(59)(60)(61), and also of numerous autoimmune diseases (62). ...
Article
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Gonadectomy is widely used to treat and prevent behavior problems including the aggressive behavior of dogs. The aim of this study was to determine whether aggressive behavior toward familiar people, strangers, or other dogs was significantly different in dogs gonadectomized at various ages vs. intact dogs using the Canine Behavioral Assessment Research Questionnaire (C-BARQ) with multivariate analysis. Of 15,370 initial surveys, those for dogs reported to have been gonadectomized at less than 6 weeks of age or to correct a behavior problem, and those with incomplete answers to questions regarding independent or dependent variables were excluded, leaving 13,795 for the analysis of aggressive behavior toward familiar people: 13,498 for aggressive behavior toward strangers and 13,237 for aggressive behavior toward dogs. Aggressive behavior was defined (a) using mean scores for all questions on the C-BARQ for aggressive behavior (range 0–4) and (b) comparing dogs with no aggressive behavior (all questions answered 0) to dogs with moderate or severe aggression (at least one score of 2, 3, or 4). Data for intact dogs were compared with those for dogs gonadectomized at 6 months or less, 7–12 months, 11–18 months, and >18 months. Neither gonadectomy nor age at gonadectomy showed an association with aggression toward familiar people or dogs. However, there was a low but significant increase in the odds of moderate or severe aggression toward strangers for all gonadectomized dogs compared with intact dogs, but this effect was driven entirely by data for dogs gonadectomized at 7–12 months of age, which were 26% more likely to demonstrate aggression toward strangers. This large, comprehensive study of the relationships between gonadectomy and aggressive behavior in dogs demonstrates that when the many factors affecting aggressive behavior are considered, there is no evidence that gonadectomy at any age alters aggressive behavior toward familiar people or dogs, and there is only a minimal increase in aggression toward strangers. Given the increasing evidence of significant negative health effects of gonadectomy, there is an urgent need to systematically examine other means of preventing unwanted procreation, such as vasectomy and hysterectomy.
... 1,3; eine getrennte Auswertung nach Geschlecht und Kastrationsstatus erfolgte nicht. In der zweiten Studie an insgesamt 432 Hunden waren ebenfalls kastrierte Tiere häufiger betroffen (128). Es ist jedoch davon auszugehen, dass auch Tiere Aufnahme in die Studie fanden, die aufgrund einer Patellaluxation von der Zucht ausgeschlossen und deshalb kastriert wurden. ...
Article
Advice for dog owners regarding the Pros and Cons and optimal time for neutering a female dog is complex and should be based on recent and valid research data as well as individual aspects. After taking a closer look at the literature, it becomes clear that some putative robust information has to be revised or updated. An obvious advantage of neutering a female dog is that ovarian diseases and sexual steroid-dependent diseases, including metropathy, no longer occur. In addition, it is likely that an early neutering reduces the risk to a certain extent of mammary neoplasia, even if the scientific basis for this observation is weak. The effect might be less than some earlier publications suggest. Disadvantages of neutering female dogs include urinary incontinence, which was postulated decades earlier. However, reported incidences and findings regarding factors that influence urinary incontinence, including time of neutering related to puberty, are heterogeneous. Recently, several studies have been published suggesting a significantly higher risk of different forms of neoplasia and musculoskeletal disorders in neutered dogs. However, factors that may bias these findings, including nutritional condition, age and/or housing, were not addressed in most studies. Data on effects on metabolism and the immune system are currently very limited. If owners want their female dogs to be neutered, a thorough counselling is essential that includes individual aspects as well as breed- and housing-specific factors. The optimal time may be between the first and the second heat. It can be suggested, that at this time, a certain reduction of the risk of mammary neoplasia can be achieved with only a moderate potential for undesired side effects.
... 6,7,[12][13][14] Neuter status seems to be a risk factor, with neutered dogs having about 3 times the odds of developing patellar luxation. 14,15 Most of the dogs are affected unilaterally; however, bilateral luxation may be a common finding. 7,16 Patellar luxation is a typical disease of young dogs, but clinical signs become often evident as the animal grows. ...
Article
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Patellar luxation is a common orthopedic problem in dogs. Medial luxation is more common than lateral luxation and is usually diagnosed in dogs of small breed. Diagnosis is based on clinical evidence of patellar instability; however, diagnostic imaging is required to assess the amount of skeletal deformity and then the most appropriate method of treatment. Surgical options include both soft tissue and osseous techniques, however, in most of the cases, a combination of more procedures is used to achieve the correction of the luxation. Complication rate is generally low and the most common complications include reluxation and implant-associated complications. Prognosis is generally favorable, with most of the dogs returning to normal limb function. This article describes patellar luxation features in dogs, including clinical presentation, diagnosis, and treatment options available.
... The only exception is a report by Lavijsen et al. (2013), who found LPL to be more common than MPL in Flat-Coated Retrievers. BPL was diagnosed in 2.9% of Pomeranians, a lower proportion than that reported earlier for small-and miniature-breed dogs (6.5%) (Vidoni et al., 2006), Kooiker dogs (7%) (Wangdee et al., 2014), and Flat-Coated Retrievers (8%) . ...
Article
The genetics of patellar luxation (PL) were investigated in Pomeranian dogs presented at the Small Animal Hospital, Faculty of Veterinary Science, Chulalongkorn University. A cohort of 339 Pomeranian dogs, part of a four-generation pedigree of 842 Pomeranians, was screened for PL from 2006 to 2013. PL was present in 77% of the screened dogs, with 84% having bilateral and 16% unilateral luxation. Medial PL was more common (95%) than lateral PL (2%) or bidirectional PL (3%). The risk of PL was similar in male and female dogs (female:male relative risk 1.11, 95% CI 0.98–1.25). The heritability of PL in the screened population was 0.44 ± 0.04 using a threshold model. A genome-wide association study of PL (48 cases and 48 controls) using a high-density SNP array indicated the possible involvement of 15 chromosomal regions, of which CFA05 and CFA32 remained associated in a larger study involving an additional 128 cases and 7 controls. Candidate genes in these regions may be involved in the pathogenesis of PL in Pomeranian dogs.
... The degrees of PL were classified into four grades, as determined by manipulation [1,24,25] . Grade I: The patella can be luxated from the femoral groove when the stifle was fully extended and the patella can return into the femoral groove immediately. ...
... Patellar luxation (PL) is a major hereditary orthopaedic abnormality observed in a variety of dog breeds (Gibbons et al. 2006;Vidoni et al. 2006;Lavrijsen et al. 2013;Wangdee et al., 2014). Normally, the patellae are located within the trochlear groove of the femur at a fixed distance to the tibial crest and have only limited sideways movement within this groove. ...
Article
Patellar luxation (PL) is one of the major hereditary orthopaedic abnormalities observed in a variety of dog breeds. When the patellae move sideways out of the trochlear groove, this is called PL. The PL score varies between dogs from normal to very severe. Reducing the prevalence of PL by breeding could prevent surgery, thereby improve welfare. Orthopaedic specialists differentiate between normal and loose patellae, where the patellae can be moved to the edge of the trochlear groove, considering scoring loose patellae as normal in the future. Loose patellae are considered acceptable for breeding so far by the breeding organization. The aim of this study was to analyse the genetic background of PL to decide on the importance of loose patellae when breeding for healthy dogs. Data are available from two dog breeds, that is Flat-coated Retrievers (n = 3808) and Kooiker dogs (n = 794), with a total of 4602 dogs. Results show that loose patellae indicate that dogs are genetically more susceptible to develop PL because family members of the dogs with loose patellae showed more severe PL. In addition, the estimated breeding values for dogs with loose patellae indicate that breeding values of dogs with loose patellae were worse than breeding values obtained for dogs with a normal score. Given these results, it is advised to orthopaedic specialists to continue to score loose patellae as a separate class and to dog breeders to minimize the use of dogs in breeding with a genetically higher susceptibility for PL.
... The patella can luxate medially, laterally or both in a medial and lateral direction (Vidoni et al. 2006). The term bidirectional patellar luxation (BPL) is used when the patella luxates both medially and laterally. ...
... Medial PL was more common than lateral PL, but similar to that reported in other studies of PL (Remedios et al., 1992;Roush, 1993;Hayes et al., 1994;Gibbons et al., 2006;Alam et al., 2007). Bidirectional PL was diagnosed in 7% of Kooiker dogs, similar to values reported in small and miniature breed dogs (6.5%) (Vidoni et al., 2006), and in large breed dogs (8%) (Lavrijsen et al., 2013). ...
Article
The prevalence of patellar luxation (PL) and genetic factors potentially involved in the disorder were investigated in Dutch Kooiker dogs. A cohort of 842 Kooiker dogs, the offspring of 195 sires and 318 dams, was screened for PL from 1994 to 2011. The cohort was included in a pedigree of 1737 Kooiker dogs comprising nine generations. PL was present in 24% of screened dogs, with unilateral and bilateral luxation being observed equally frequently. Medial PL was more common (61%) than lateral PL (32%) or bidirectional PL (7%). The frequency of PL was similar in male and female dogs, with a female:male relative risk of 1.15 (95% confidence interval, CI, 0.90-1.48). The heritability of PL in the screened population was 0.27 ± 0.07. Since the start of the screening programme, the prevalence of PL decreased from 28% to 19%. A genome-wide association study of PL with 48 cases and 42 controls suggested the possible involvement of a region on chromosome 3 (Praw = 1.32 x 10-5, Pgenome = 0.142), but the involvement of this region could not be confirmed in a validation group. Breeding programmes for complex diseases, such as PL, would benefit from combining pedigrees, phenotypes and genotypes, i.e. from genomic selection, as is currently the method of choice for breeding of production animals.
... A large number of dogs present primarily bilateral MPL, which strongly suggests a hereditary disorder (2). However, familial anamneses and heredity studies are required in order to construct a genetic background (5). ...
Article
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This prospective study used radiographic techniques to evaluate the inclination, Norberg, quadriceps and femoral varus angles, and the patellar position in dogs with developmental medial patellar luxation. The study also compared these measurements pre- and post-operatively to determine how they were affected by surgical procedures. Eighteen dogs with unilateral or bilateral luxation were used, and 4 groups were established according to luxation grade. Except for the quadriceps angle, there was no difference among the groups preoperatively. Significant differences for the quadriceps angle were observed between Grades 1 and 3, and between Grades 2 and 3. The Norberg and femoral varus angles and the patellar position showed no changes between pre- and postoperative groups. However, measurements of the preoperative quadriceps angle and postoperative inclination angle may be useful for evaluating dogs with grade-3 luxation. Further studies using other imaging techniques are required in dogs with severe grade-4 luxation due to the difficulty in obtaining a good radiographic position.
Chapter
Canine sports medicine and rehabilitation is one of the newest specialties in veterinary medicine. It encompasses and integrates a variety of fields, including orthopedics, exercise physiology, neurology, cardiology, pulmonology, nutrition, and others. Rehabilitation, which includes regaining and maintaining fitness as well as conditioning targeted towards prevention of future injury, is a critical partner to canine sports medicine. Canine athletes include dogs that compete in performance events as varied as agility trials, obedience trials, and disc dog competitions, as well as working dogs such as police/military dogs, search and rescue dogs, and assistance dogs for the disabled. Principles of canine sports medicine and rehabilitation apply to all active dogs, regardless of whether they train or compete; this comprises a large proportion of the canine population. Canine sports medicine and rehabilitation professionals play a pivotal role in helping canine athletes and working dogs recover after injury or illness. They work to prevent re-injury while moving the patient back to a state of muscular ability, endurance, coordination, balance, and flexibility that optimizes their physical abilities. Understanding the physical activities that are involved in different performance events and the jobs that working dogs perform is critical to devising targeted rehabilitation for sports/working dogs after injury or illness, and for retraining them to perform their specific duties. This is best accomplished by attending athletic/working dog training sessions and competitions.
Article
This study was aimed to evaluate canine vasocystotomy as a testosterone-preserving method of sterilization and investigate its potential post-operative complications. Five healthy adult male dogs underwent surgical procedure to transplant vasa deferentia to the urinary bladder. Under general anesthesia, caudal abdomen was opened and both vasa deferentia were ligated and transected. Then, the proximal free ends were sutured to mucosal layer of urinary bladder on its cranio-dorsal aspect. Serum testosterone level was measured on a weekly basis. Six-week postoperative assessments were performed including semen and urine sampling, ultrasound, contrast vasography, and tissue sampling. Statistical analyses revealed no significant differences in serum testosterone levels compared to its baseline value. Along with non-motile and broken spermatozoa, no cast or crystals were observed in urine samples. Semen analyses revealed azoospermia. No vasal obstruction or contrast leakage was observed in vasographs indicating bilateral patency in all dogs. Normal thickness of the bladder was found in ultrasounds. Histopathology showed normal testicular architecture and no inflammatory response was found in bladder or vas deferens following vasal transplantation. No significant change was found in testicular volume at the end of the study. This study suggested that vasocystostomy could be considered as an alternative method for canine sterilization with no significant changes in the testosterone concentrations and no evidence of postoperative complications. The preservation of testosterone could be regarded as an advantage and makes this approach favorable compared to the routine methods of sterilization especially for herding and guard dogs, because it prevents overpopulation while maintains the functionality.
Chapter
Canine sports medicine and rehabilitation is the newest specialty in veterinary medicine. It encompasses and integrates a variety of fields, including orthopedics, exercise physiology, neurology, cardiology, pulmonology, nutrition, and others. Rehabilitation, which includes conditioning, maintaining, and regaining fitness, is a critical partner to canine sports medicine. Canine athletes include dogs that compete in performance events as varied as agility trials, obedience trials, and disc dog competitions, as well as working dogs such as police/military dogs, search and rescue dogs, and assistance dogs for the disabled. Canine sports medicine and rehabilitation professionals play a pivotal role in helping canine athletes and working dogs recover after injury or illness. They work to prevent reinjury while moving the patient back to a state of muscular ability, endurance, coordination, balance, and flexibility that allows them to train and compete as well as or perhaps better than they did before. Understanding the physical activities that are involved in the different performance events and the jobs that working dogs perform is critical to devising targeted rehabilitation for sports/working dogs after injury or illness, and for retraining them to perform their specific duties. This is best accomplished by attending athletic/working dog training sessions and competitions.
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Objective: To investigate associations between age at gonadectomy and estimated risk or age at diagnosis of neoplastic and behavioral disorders in Vizslas. Design: Retrospective cohort study. Animals: 2,505 Vizslas born between 1992 and 2008. Procedures: Data on demographics, gonadectomy status, and age at diagnosis of disease or disorder were obtained with an anonymous online survey and analyzed. Results: Dogs gonadectomized at ≤ 6 months, between 7 and 12 months, or at > 12 months of age had significantly increased odds of developing mast cell cancer, lymphoma, all other cancers, all cancers combined, and fear of storms, compared with the odds for sexually intact dogs. Females gonadectomized at ≤ 12 months of age and males and females gonadectomized at > 12 months of age had significantly increased odds of developing hemangiosarcoma, compared with the odds for sexually intact dogs. Dogs gonadectomized at ≤ 6 months of age had significantly increased odds of developing a behavioral disorder. The younger the age at gonadectomy, the earlier the mean age at diagnosis of mast cell cancer, cancers other than mast cell, hemangiosarcoma, lymphoma, all cancers combined, a behavioral disorder, or fear of storms. Conclusions and clinical relevance: Additional studies are needed on the biological effects of removing gonadal hormones and on methods to render dogs infertile that do not involve gonadectomy. Veterinarians should discuss the benefits and possible adverse effects of gonadectomy with clients, giving consideration to the breed of dog, the owner's circumstances, and the anticipated use of the dog.
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A standard diagnostic procedure for patellar luxation is described. It is based upon the patellar luxations grade 1 to 4, which have been published before, and contains additional definitions in terms of the animals positioning toward the examinator.
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A standard classification for patella luxation has been established in Switzerland and was presented to private veterinarians in a series of continuing education courses. The diagnostic efficiency, sensitivity and specifity has been evaluated. The success rate of 88 % agreement between the diagnosis made by the participants and the references of the University Veterinary Teaching Hospital in Zurich is quite satisfying. Difficulties were mainly seen in the diagnosis of patella luxation grade 1 and 4. The test performed by the participants showed that when a medial and a lateral patella luxation were present in the same stifle, quite often the lateral luxation was missed and only the medial luxation was diagnosed. Fortunately this has no consequences for the breeding selection of toy breeds, because the medial patella luxations are of higher grade.
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Thirty-four dogs that had surgical correction of medial patellar luxation (MPL) in 52 stifle joints were examined after a minimum follow-up period of 1 year (median, 3.6 years). The dogs were divided into the following three groups depending on their age at the time of surgery: group 1, 3 to 6 months; group 2,8 to 20 months; and group 3,2.2 to 12 years. Two of the dogs in group 3 had ruptured their cranial cruciate ligament in addition to having MPL. The results were based on a clinical assessment of the animal's gait, and physical and radiographic examination of the stifle joints. Six of seven stifle joints evaluated in group 1 had radiographic evidence of moderate to severe degenerative joint disease of the patellofemoral joint, and in two of the joints recurrence of MPL was observed. Failure to maintain reduction of the patellofemoral joint was also observed in 11 of 22 (50%) and 12 of 23 (52%) of the stifle joints in groups 2 and 3, respectively. In the latter groups, mild degenerative joint disease was evident radiographically in stifle joints that had maintained reduction of the patellofemoral joint as well as in those joints that had not maintained reduction. Four of the 34 dogs were consistently (n = 2) or intermittently (n = 2) lame; the two dogs that were consistently lame had cranial instability of the stifle consistent with rupture of the cranial cruciate ligament. In the latter two dogs, the cranial cruciate ligament had been intact at the time of surgery for correction of MPL.
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To measure the quadriceps angle (Q-angle) in dogs with congenital patellar luxation using magnetic resonance (MR) methods. Prospective clinical study. Thirty-eight client-owned dogs. Thirty-eight dogs were examined and placed into the following groups based on the degree of patellar instability: normal, grade I, grade II, and grade III. MR images of 37 pelvic limbs without patellar instability, 33 pelvic limbs with patellar luxation, and 6 limbs with cranial cruciate ligament (CrCL) rupture were made. The Q-angle was calculated using trigonometric methods based on MR images. Limbs with patellar luxation were compared with normal stifles and stifle with other disorders. The average Q-angle of the normal group was 10.5 degrees (24.9 degrees to -2.0 degrees ). The grade I group had an average Q-angle of 12.2 degrees (28.8 degrees to 2 degrees ), the grade II group 24.3 degrees (44.6 degrees to 7.7 degrees ), and the grade III group 36.6 degrees (51.4 degrees to 15.6 degrees ). The average Q-angle of limbs with an isolated CrCL rupture was 19.3 degrees (34.7 degrees to 3.9 degrees ). MR images can be used to make exact calculations of the Q-angle. MR images can be used to quantify the degree of patellar luxation.
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A wire-suture method was used for correcting grade IV medial and lateral luxations of the patella. In seven operated stifles, the method resulted in a normal gait and minimal valgus and varus deformity of the distal femur and proximal tibia.
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Canine patellar luxation is seen in toy and miniature breeds, and in the majority of cases the problem is medial patellar luxation. When the luxation is left alone, it causes deformity and disorder in the growth of the affected limb. In severe cases, the limb may cease to afunction. Early surgical correction is therefore essential, but the owners are not able to detect the disorder at an early age and surgical intervention in most cases will take place after 6 months of age. The authors were able to have the opportunity to operate at an earlier age by educating breeders and owners. Various techniques have been developed and implemented to correct this disorder with varying therapeutic results. The authors have devised a unique surgical method which has been applied to the numerous cases with good results since 1985. The procedure is to make a longitudinal groove on the medical cortical bone of the tibial tuberosity along the tibial crest, and to place small pieces of artificial ceramic bone or autoplastic bone grafts in the groove, thus laterally transposing the tibial tuberosity and crest. This method makes it possible to put the quadriceps muscles of the thigh, the patella and the patellar ligament in the correct alignment over the femoral trochlea. It is considered appropriate to conduct this operation at 1.0-3.0 months of age when the dog has matured enough to be able to withstand anesthesia and surgical stress.