The pathogenesis and diagnosis of canine hip dysplasia: a review.

Hip dysplasia is a common developmental problem affecting the canine population. Despite extensive research into the condition, many questions remain unanswered and numerous misconceptions are present among the general public. The purpose of this paper is to review the current knowledge on the development of hip dysplasia, factors modifying its development, and current diagnostic techniques. A computerized literature search was conducted for the period of January 1983 to April 1985 using the MEDLINE and CAB databases, and the keywords hip dysplasia, hip, dog, and canine. Other articles, wherever possible original research articles, published before 1983 were also reviewed. Animals affected by hip dysplasia are born with normal hips, but quickly develop subluxation of the femoral head. Degenerative joint disease follows. Hip dysplasia is a complex, inherited, polygenic trait. Selective breeding of only normal dogs with normal littermates, parents, and grandparents is the recommended method of reducing the incidence in the general population. Gene expression in affected individuals may be modified by a number of environmental factors. These factors do not cause hip dysplasia, but they alter manifestations of the trait and its severity. Nutrition is a major environmental factor. Excess energy consumption increases the frequency and severity of hip dysplasia in genetically predisposed dogs. Food intake should be regulated to maintain a slender figure with the ribs and dorsal vertebral spines easily palpable, but not visible. Excess dietary calcium and vitamin D contribute to hip dysplasia in genetically predisposed individuals and should be avoided. High dose vitamin C supplementation in growing puppies does not prevent hip dysplasia, and this practice should be discontinued.(ABSTRACT TRUNCATED AT 250 WORDS)     

The pathology of canine hip dysplasia.

Although the complete pathogenesis of cartilage damage in canine hip dysplasia has not been completely worked out, it appears that joint laxity with resultant excessive stresses upon articular cartilage is the initiating factor. Grossly, this damage is characterized by cartilage thinning with potential exposure of subchondral bone, osteophyte formation, and pannus formation. Microscopically, there is a marked variation in chondrocyte cellularity, with focal regions of hypocellularity and chondrocyte clusters and synovial lining cell hyperplasia and hypertrophy as well as a decrease in proteoglycan content. This latter change has been substantiated biomechanically. Ultrastructural studies indicate that there is extensive alteration of collagen organization within the cartilage.     

The role of nutrition in canine hip dysplasia.

The role of nutrition in canine hip dysplasia is a multifactorial as the disease itself. Large and giant breeds primarily are at risk for the disease. Rate of growth, feeding methods, feed consumption, specific nutrients, and electrolyte balances within the diet have all been shown to influence hip dysplasia. Known nutritional risk factors are rapid weight gain and excessive calcium supplementation. Nutritional factors with less secure roles in their influence on the disease process are vitamin C, protein, and carbohydrates. There exists a need to identify further and control the various nutritional factors in the diet that influence canine hip dysplasia.     

Radiographic development of canine hip dysplasia.

The radiographic changes observed in the development of CHD in the dog are complex and not fully understood despite years of research. Moderate to severe CHD is relatively easy to diagnose using standard radiographic views and evaluation techniques. However, early detection of mild or borderline CHD continues to be difficult to reliably detect radiographically. Efforts continue to be made to develop new views, techniques, and evaluation methods that will improve the radiographic evaluation of CHD. Until better methods are proven, the standard ventrodorsal leg extended view, evaluated by an experienced reviewer, will remain the method of choice for radiographic detection of CHD.     

Controlling canine hip dysplasia in Finland.

The aim of the study was to evaluate the Finnish Kennel Club's hip-dysplasia screening and control programs. As a retrospective study, records of hip-dysplasia screening of 69,349 dogs in 22 breeds that were born in 1988-1995 were analyzed and compared to data from prior to 1988. In most breeds, no significant changes in dysplasia prevalence could be found. In English cocker spaniels, golden and Labrador retrievers and Rottweilers a significant decrease - but in boxers, Dobermans, German Shepherd dogs and rough collies a significant increase - in prevalence was detected. In flat-coated retrievers overall prevalence increased - but the prevalence of severe hip-dysplasia decreased significantly during the study period. The present control program has not resulted in fast progress. Selecting against hip-dysplasia cannot be expected to be very effective, when based only on mass selection on phenotypic observations. Predicted breeding values based on progeny testing would probably give better results. Also, breeders' compliance and commitment to programs is not always high and other selection criteria in breeding are thought to be more important. Modern society has high demands for animal welfare and consumer issues, and breeders and kennel societies should pay more attention to health issues in breeding pedigreed dogs.     

Total hip arthroplasty for treatment of canine hip dysplasia.

Cemented THA is an established procedure for treating arthropathies of the hip in large, healthy mature dogs. CHD with secondary osteoarthritis is the most common indication. Although comparative studies between THA and excision arthroplasty have not been reported, our experience with both procedures and studies in the literature support THA as the best available treatment for crippling degenerative joint disease secondary to CHD in large, mature dogs. Negative aspects of the procedure include high cost, the potential of significant complications, and the sophisticated surgical technique required. Improvements in patient selection, design of implants, surgical technique, and postoperative care have decreased the incidence of complications and improved the success rate to over 90%. However, concerns in human applications about cement disease and the desire to increase the functional life of the prosthesis have renewed interest in cementless systems. Advantages of cementless THA are fixation via bony ingrowth and avoidance of problems associated with PMMA. Important technical aspects of cementless THA relate to optimal fit and fill so that the prosthesis is stable, bone ingrowth is promoted, and weight-bearing forces are transferred to the proximal femur physiologically. Problems recognized with cementless systems include fissure fracture, bone resorption, and excessive motion between the implant and bone. Currently, investigations are being conducted to develop prosthetic materials that more closely match the stiffness of bone, stem designs that provide optimal fit and maintain normal strain patterns in the bone, and coating materials that promote permanent fixation by bone ingrowth. Early clinical results in humans and research results in dogs have been encouraging but have not withstood the test of time. Results of cementless techniques must be compared to the standards set by cemented THA over the last 20 years in humans and the last 10 years in dogs.     

Treatment of canine hip dysplasia: a review.

This article discusses the treatment approaches and recommendations for canine hip dysplasia. A search of the literature database MEDLINE (1969-1994) was conducted and relevant journal articles regarding the medical and surgical treatment of hip dysplasia were selected and reviewed. Dysplastic dogs can be divided, for treatment purposes, into those with no or minimal osteoarthrosis, and those with moderate to severe osteoarthrosis. In young animals with joint laxity and pain, but with no or minimal radiographic evidence of osteoarthrosis, the treatment approach is controversial. Conservative management may be effective in the short term, but progressive development of osteoarthrosis occurs and clinical signs may manifest at an older age. Options for surgical treatments in these young dogs include pectineal myectomy, lengthening of the femoral neck, and corrective osteotomies. Corrective osteotomies are advocated to reestablish joint congruency and prevent development of osteoarthrosis. In the mature osteoarthritic dog, effective conservative management depends on the severity of the degenerative joint disease. Proposed surgical treatments for clinically debilitating hip dysplasia include biocompatible osteoconductive/shelf arthroplasty; femoral head and neck excision arthroplasty, with or without muscle sling interposition; and total hip replacement. Although research directly comparing the salvage procedures has not been reported, studies suggest that total hip replacement is more effective in returning large dogs to full functional weight bearing.     

犬髋关节发育异常的诊断进展

犬髋关节发育异常是最常见的矫形外科疾病 ,遗传力在 0 2～ 0 6之间。过去诊断主要靠临床经验和触诊 ,但准确率不高。本文主要介绍了主观髋关节打分法、Norberg角、股骨头被覆率、分离指数法、髋臼背缘等X—线摄像诊断方法 ,为本病快速准确诊断及种犬的选择提供了理论依据。     

犬髋关节发育异常的手术治疗进展

犬髋关节发育异常（Canine hip dysplasia,CHD）是遗传和环境应激因素所致的复合性疾病,也是最常发生的矫形外科疾病,其主要特征是髋臼变浅,股骨头变形,髋关节不同程度的松弛、半脱位或全脱位,最终发展为严重的退行性关节炎。通过触诊、临床症状及骨盆X-线摄片技术可进行诊断。犬髋关节发育异常的治疗包括保守的药物治疗及手术治疗。     

Pectineus tendon surgery for the management of canine hip dysplasia.

Pectineus tendonectomy is a useful procedure for relieving pain and rehabilitating the dysplastic dog in select cases. Relief of pain is believed to come from a combination of releasing tension on the hip joint capsule and providing a better loading contact surface on the articular cartilage owing to the increased abduction of the hind legs after surgery. Some pain relief also may come from the release of tension on the pectineus muscle. The modified procedure described in this article results in less seroma formation and less reattachment of the severed ends of the pectineus tendon of origin than the procedure originally described by the author.     

Influence of anaesthesia on canine hip dysplasia score

Hip dysplasia (HD) scores, based on the five grades, as defined by the Fédération Cynologique Internationale, were compared between anaesthetized (group 1, n = 3839) and non-sedated non-anaesthetized dogs (group 2, n = 1517). Each dog was radiographed in the standard ventro-dorsal hip joint extended position. Each radiograph was evaluated by the same reader blinded regarding the dog's status of anaesthesia. Results showed that there was a significant difference in hip dysplasia prevalence between group 1 (22%) compared with group 2 (9%) (P < 0.005). This difference was the result of a lower rate of hip-joint laxity assessment and the measurement of Norberg-Olsson angle <105 degrees in group 2 compared with group 1. The acetabular and femoral morphologies were not significantly different between the groups. The data confirm that the scoring of dogs for HD on standard radiographs with the hip joints extended is influenced by anaesthesia.     

犬髋关节发育不良候选基因的研究进展

髋关节发育不良是一种多基因遗传性疾病,几乎所有品种的犬都可发生此病,在医学上是小儿骨科常见的严重危害儿童健康的先天畸形之一。该病在遗传病因学方面尚无明确的定论,目前研究发现雌激素及受体基因、胶原基因、Hox基因、主要组织相容性抗原基因、生长分化因子5基因等多态性与髋关节发育不良存在一定的相关性。