Risk factors for ventral luxation in canine total hip replacement

Objective— To identify risk factors associated with ventral luxation (VL) of canine total hip replacement (THR), and outcome.
Study Design— Retrospective study.
Animals— Dogs (n=602) that had THR (563 cemented, 35 cementless, 4 hybrid).
Methods— Dogs (1999–2004) with VL after THR were compared with dogs with uncomplicated THR. Data included signalment, body weight, diagnosis, implant size, acetabular cup orientation, and femoral displacement ratio (FDR).
Results— VL was diagnosed in 11 (1.8%) dogs after primary THR. Including 2 other dogs that had VL after the study period, 10 (77%) of 13 dogs had VL within 7 days of surgery. Risk factors for VL included Saint Bernard-type dogs ( P =.0001), short neck extension ( P =.0005), and high angle of lateral opening in other breeds ( P =.018). There were trends toward higher risk of VL with lower FDR in Saint Bernardtypes ( P =.060), and with cementless implants ( P =.061). Twelve dogs had revision arthroplasty that was successful in all cementless and 2 cemented VL cases. Five dogs had recurrent VL and a poor outcome.
Conclusion— VL is generally an early complication of THR, with no single common risk factor identified.
Clinical Relevance— Saint Bernard types and short neck extensions are associated with increased risk of VL. Poor cup orientation is a determining factor for VL in some dogs, but a protective orientation of the acetabular cup was not found. Revision is successful in most dogs, but recurrent VL merits a guarded prognosis.     

Arthroscopic release of the medial femoropatellar ligament for canine medial patellar luxation

Five dogs of varying breeds and ages were presented for evaluation of medial patellar luxation that was unresponsive to conservative treatment. Arthroscopy of each affected stifle was performed, and adequacy of the femoral trochlea and patellar tracking in the trochlea were assessed. Medial femoropatellar ligament release was then performed using a bipolar radiofrequency electrosurgical system with or without a tibial tuberosity transposition. The procedure resulted in good to excellent outcomes for four dogs and a fair outcome for a fifth dog.     

Short-term evaluation of dorsal acetabular augmentation in 10 canine total hip replacements

OBJECTIVE: To report the use of dorsal acetabular augmentation (DAA) in canine total hip arthroplasty (THA) and to evaluate the clinical and radiographic outcome after a minimum of 1 year follow-up. STUDY DESIGN: Clinical study. ANIMALS: Nine dogs that had THA. METHODS: Ten hips requiring acetabular augmentation for optimum acetabular cup implantation for THA were evaluated retrospectively. The excised femoral head and neck was used as the corticocancellous bone graft for index THA surgeries, and the dorsal crest of the ipsilateral ilial wing was used as the bone graft in 1 dog that had a revision surgery. Clinical and radiographic follow-up examinations were performed at approximately 8 weeks and 1 year postoperatively. Long-term radiographic examinations included use of a standing dorsal acetabular rim (DAR) projection for assessment of graft-recipient boundary. Functional clinical outcome was assessed using direct patient evaluation and telephone interview. RESULTS: One dog failed to regain limb function after surgery. Suspected aseptic loosening of the acetabular cup was observed on radiographs approximately 12 weeks postoperatively. Excluding this single explantation, follow-up physical and radiographic examinations indicated good implant and graft positioning and normal function for all dogs. CONCLUSIONS: Acetabular augmentation permitted implantation of an appropriately sized acetabular cup while maintaining complete DAR coverage of the prosthesis. Nine out of 10 hips had a successful outcome with minimal radiographic and no functional abnormalities. Further follow-up is necessary to determine the long-term outcome of DAR augmentation in canine THA. CLINICAL RELEVANCE: Acetabular augmentation with an autogenous corticocancellous bone graft constructed from the femoral head and neck can provide complete DAR coverage to permit use of an appropriately sized acetabular cup in THA.     

Modified De Vita pinning technique for the management of canine hip luxation: preliminary findings

OBJECTIVE: To describe for the first time a modification of the De Vita pinning technique to manage hip luxation in the dog and to assess its use in a preliminary study. DESIGN: A prospective, clinical study using five client-owned dogs with naturally occurring injuries. PROCEDURE: A modified De Vita pinning technique was employed, using a nonthreaded Steinmann pin to reduce the risk of trauma to the sciatic nerve during pin insertion. The pin was anchored by implanted Kirschner-Ehmer clamps in an attempt to lower the risk of postoperative pin migration. RESULTS: Surgical outcome was very favourable with respect to pain on manipulation, restriction of range of movement and lameness in all dogs as assessed by veterinary examination. In four of five dogs, owners also reported normal movement at rest, walk and trot. The fifth dog was lost to follow-up. CONCLUSION: This preliminary study found that a modified De Vita pinning technique was useful in dogs with uni and bilateral hip luxation and hip luxation in the presence of other limb injuries. The modified technique may provide a sound surgical alternative to existing procedures. The described modification allows the use of a nonthreaded pin and also substantially reduces the risk of postoperative pin migration.     

The canine stifle joint II. Medial luxation of the patella

A method of assessment of cases of medial luxation of the patella for deciding the type of surgical intervention is described. The results of treatment of the cases after such an assessment indicate that, if there is no gross distortion and no deviation of the tibial tuberosity, simple lateral capsular overlap gives a satisfactory return of function, even in cases of irreducible patellar luxation.
Résumé. Les auteurs décrivent une méthode propre à évaluer les luxations médiales de la rotule en vue de déterminer la nature de l'intervention chirurgicale à pratiquer. Les résultats thérapeu-tiques obtenus sur la base de cette évaluation portent à conclure que, sauf grave déformation ou déviation de la tubérosité du tibia, le simple chevauchement capsulaire latéral permet de rétablir un état fonctionnel satisfaisant, měme dans les cas de luxation rotulaire irréductible.
Zusammenfassung. Es wird eine Methode zur klinischen Beurteilung von Fällen einer medialen Luxation der Patella zwecks Entscheidung über die Art des erforderlichen chirurgischen Eingriffs beschrieben. Die Behandlungsergebnisse in den Fällen nach einer solchen Beurteilung zeigen, dass beim Fehlen einer makroskopischen Verformung und einer Abweichung der Tuberositas tibiae die einfache laterale Kapselüberlappung eine zufriedenstellende Rückkehr der Funktion selbst in Fällen nicht reduzierbarer patellarer Luxation ergibt.     

Morphometric assessment of the canine hip joint using the dorsal acetabular rim view and the centre-edge angle

The dorsal acetabular rim (DAR) view of the hip joint can be used to assess the weightbearing portion of the acetabulum and the acetabular coverage, providing an adjunct to the conventional ventrodorsal (VD) view in the radiographic evaluation of hip dysplasia in the dog. A quantitative index of acetabular coverage in the DAR view, the acetabular slope (AS) angle, was originally proposed in 1990. The aim of the present study was to make a prospective, comparative assessment of a new parameter, the centre-edge (CE) angle, with the AS angle, for the evaluation of the acetabular coverage of the femoral head in the DAR view. The reliability and repeatability of the two parameters was assessed using the r(I) value of intraclass correlation coefficient (ICC) in a prospective study of 208 hip joints in large and giant breed dogs. An estimation of the added value of using the DAR view, compared with that of the VD standard view alone, was also assessed. The CE angle showed a higher r(I) value compared with the AS angle; in 26 per cent of hips of FCI classes A, B and C, the DAR view provided additional diagnostic information compared with the VD view, with respect to lateralisation and/or initial changes to the dorsal rim. It is concluded that the CE angle is more reliable than the AS angle in the evaluation of acetabular coverage, and that the DAR view provides valuable data compared with the VD view alone in the early stages of canine hip dysplasia.     

Mandibular canine tooth luxation injury in a dog

A mixed breed dog was presented for lateral luxation of the mandibular left canine tooth following oral trauma. This case report describes the management of this injury including reduction, stabilization using a wire reinforced acrylic splint, and standard endodontic therapy of the mandibular left canine tooth.     

Changes in the hip joint of the dog following traumatic luxation

A report is presented, on the changes occurring in the hip joints of thirty-four dogs, following treatment of traumatic coxofemoral luxation.
The animals were examined from 2 weeks to 7 years after treatment of the original injury. Twenty of the hips re-examined showed radiographic and/ or clinical abnormalities. These changes are divided into three classes, in accordance with the presence of persistent coxofemoral luxation and consequent pseudoarthrosis (or false joint) formation; coxofemoral arthritis; and asymptomatic exostosis of the ilium.
Résumé. L'auteur présente des observations concernant les modifications observées au niveau de la hanche chez 34 chiens traités pour une luxation coxo-fémorale traumatique. Les animaux avaient été examinés de 2 semaines à 7 ans après le traitement du traumatisme initial. Dans 20 cas on a trouvé des modifications cliniques ou radiologiques ou les deux à la fois au cours des nouveaux examens. Ces modifications étaient de trois sortes: persistance de la luxation coxofémorale avec formation ultérieure d'une pseudarthrose (fausse articulation); arthrite coxofémorale; exostose asymptomatique de l'os iliaque.
Zusammenfassung. Ein Bericht über die in den Hüftgelenken von 34 Hunden nach der Behandlung traumatischer coxofemoraler Luxation eintretenden Veränderungen wird vorgelegt.
Die Tiere wurden 2 Wochen bis 7 Jahre nach der Behandlung der Verletzung untersucht. Zwanzig der wiederuntersuchten Hüften zeigten radiographische und bzw. oder klinische Anoxmalitäten. Je nach dem Vorhandensein persistierender coxofemoraler Luxation und sich daraus ergebender Pseudoarthrose, d.h. Neubildung eines Gelenks an falscher Stelle, coxofemoraler Arthritis und asymptomatischer Exostose des Iliums wurden die Veränderungen in drei Klassen cingeteilt.     

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.     

Evaluation of the association between medial patellar luxation and hip dysplasia in cats.

OBJECTIVE: To investigate the association between hip dysplasia (HD) and medial patellar luxation (MPL) in cats. DESIGN: Cross-sectional prevalence study. ANIMALS: 78 cats. PROCEDURE: A complete history was obtained. Cats were examined to detect MPL and HD. Radiographs of the stifle and hip joints were obtained. Hip joints were evaluated by use of Norberg angle, distraction index, and scoring consistent with that established by the Orthopedic Foundation for Animals. RESULTS: There were 43 male and 35 female cats mean age, 2.5 years). Eleven cats had clinical signs of disease in the pelvic limbs. Medial subluxation of the patella (subgrade 1) was seen in 31 of 33 cats with otherwise normal stifle joints. Medial patellar luxation was found in 45 of 78 (58%) cats, and 35 of 45 (78%) had grade-1 MPL. Bilateral MPL was seen in 32 of 45 (71%) cats. A weak association existed between MPL and HD, because cats were 3 times more likely to have HD and patellar luxation than to have either condition alone. Concurrent MPL and HD were detected in 19 of 78 (24%) cats, and HD was diagnosed radiographically in 25 of 78 (32%) cats (19 mild, 4 moderate, 2 severe). Eighteen of the 25 cats with HD had bilateral HD. CONCLUSIONS AND CLINICAL RELEVANCE: Clinically normal cats may have a certain degree of laxity in the stifle joint, evident as medial patellar subluxation (< grade 1). There is a weak association between MPL and HD, and both conditions may develop, alone or in combination, more frequently than has been reported.     

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.     

Transposition of the sacrotuberous ligament for the treatment of coxofemoral luxation in dogs

A surgical technique is described for transposition of the sacrotuberous ligament to replace the teres ligament in the treatment of coxofemoral luxation in dogs. Ten dogs with coxofemoral luxation were treated using this technique and all animals regained full limb function within two months of surgery. It is suggested that the technique could be employed in dogs suffering from all types of hip luxations.     

The pathogenesis of canine hip dysplasia.

Dogs with CHD are born with normal hips that subsequently undergo varying degrees of subluxation of the coxofemoral joint. Although the etiology of CHD is multifactorial, the pathogenesis or stages of change within the affected coxofemoral joint(s) are similar regardless of cause. With the onset of the disease, there are progressive structural changes including joint laxity and femoral head subluxation; swelling, stretching, fraying, and eventual rupture of the teres ligament; a shallow, flattened acetabulum, deformity of the head; erosion of articular cartilage, eburnation of subchondral bone, DJD; and periarticular osteophyte formation.     

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.     

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.