Excision arthroplasty of the hip joint in dogs and cats. Clinical, radiographic, and gait analysis findings from the Department of Surgery, Veterinary Faculty of the Ludwig-Maximilians-University of Munich, Germany. 1997.

From 1978 to 1989, 132 dogs and 51 cats underwent femoral head and neck ostectomy at the Department of Veterinary Surgery, Ludwig-Maximilians University, Munich, Germany. Clinical and radiographic re-evaluations were carried out an average of four years postoperatively in 81 (44%) of the animals, and gait analysis was also done in 17. The functional results were rated good in 38% of patients, satisfactory in 20%, and poor in 42%. However 96% of the owners were satisfied with the results. Kinetic and kinematic measurements showed that although femoral head and neck resection alleviated pain, it resulted in functional deficits in small as well as large breed dogs. These deficits were not visible during rapid movement.

[Anatomical and pathophysiological features and treatment of elbow luxation in rabbits]. / Untersuchungen zur Anatomie, Pathophysiologie und Therapie der Luxatio antebrachii beim Kaninchen.

OBJECTIVE: Functional anatomical evaluation of elbow luxation in rabbits and the comparison of this lesion to cats and dogs. MATERIAL AND METHODS: The relative frequency of elbow luxation and the most common direction of antebrachial bone dislocation in rabbits were compared catamnestically with data in dogs and cats. Goniometric evaluation of the range of motion of the elbow was carried out in 14 rabbits. This was followed by visualisation of the anatomical structures of cadaver elbows and measurement of the subchondral bone density of the elbow using computed tomographic osteoabsorptiometry in seven rabbits and seven cats. Finally, the stabilisation of the elbow joint using wire to replace the collateral ligaments was evaluated in cadaver specimens. RESULTS: Rabbits undergo elbow luxation approximately four times more often than cats and dogs when compared to luxation of the hip joint. Caudal elbow luxation is most commonly seen in rabbits. The elbow functions as a "snap joint" because of the eccentric insertion of the collateral ligaments and has good lateral stability, which is afforded by a sagittal crest of the humeral condyle. Computed tomographic osteoabsorptiometry showed that the caudal region of the elbow joint undergoes the most mechanical stress. CONCLUSIONS AND CLINICAL RELEVANCE: The anatomical structure of the elbow of rabbits allows primarily sagittal movement; excessive force poses a risk of injury to the cranial aspect of the joint capsule and the humeroulnar ligaments. When closed reduction and a Velpeau sling do not provide stabilisation for the treatment of elbow luxation, transosseus replacement of the humeroulnar collateral ligaments may be indicated.

Co-culture of canine mesenchymal stem cells with primary bone-derived osteoblasts promotes osteogenic differentiation.

Tissue engineering of bone grafts with osteogenic progenitor cells such as adult mesenchymal stem cells (MSC) represents a promising strategy for the treatment of large bone defects. The aim of this experimental study was to evaluate the osteogenic potential of primary osteoblasts on MSCs in co-culture at different ratios. The co-cultures were treated with or without a specific osteogenic induction medium in monolayer and high density cultures. In monolayer co-cultures, MSCs and osteoblasts actively searched for cell-cell contact leading to cell proliferation and only in treated monolayer co-cultures osteogenesis was observed. Ultrastructural evaluation of high density co-cultures using electron microscopy demonstrated osteogenesis with no significant difference between treated or untreated co-cultures. Immunoblotting confirmed expression of collagen type I, beta1-Integrin, the osteogenic-specific transcription factor Cbfa-1 and induction of the MAPKinase pathway (Shc, Erk1/2) in both treated and untreated co-cultures. Although treatment with the induction medium enhanced osteogenesis in the co-cultures compared to untreated co-cultures, the quality of osteogenesis was proportional to the quantity of osteoblasts in the co-cultures. Fifty percent osteoblasts in the co-cultures markedly increased osteogenesis; even the presence of ten percent osteoblasts in the co-culture strongly promoted osteogenesis. This data leads us to conclude that co-culture of MSCs with osteoblasts combined with the three-dimensional environment of the high density culture strongly promotes osteogenesis and stabilizes the osteogenic potential of MSCs. This approach may prove to be of practical benefit in future tissue engineering and regenerative medicine research.

Traumatic fracture of the patella in 11 cats.

Traumatic patellar fracture in cats mainly occurred in male neutered cats with an average age of four years, six months and a mean weight of 4.8 kg. Patellar fractures were concurrent with long bone fractures and cruciate ligament rupture or occurred after gunshot. The patella luxated medially or laterally in four cats. Fracture fragments were usually small, either from the proximal pole (base) or distal pole (apex) or longitudinal fragments. Treatment was by fragment excision when the fragment was small or by reconstruction with pins and wires when fractures were comminuted. The outcome in six cats was reported as 'good' to 'normal' and three cats were 'improving' or had 'mild' intermittent lameness at the last follow up.

Mechanical properties of 18 different AO bone plates and the clamp-rod internal fixation system tested on a gap model construct.

OBJECTIVE: To compare the stiffness and strength of AO bone plates (DCP, LC-DCP, VCP, RCP, and LP) and the Clamp-Rod Internal Fixation System (CRIF). STUDY DESIGN: In vitro. SAMPLE SIZE: 12 individual implants of 18 plate dimensions and four sizes of CRIF, each corresponding to 2.0, 2.4/2.7, 3.5, or 4.5 mm screw sizes. METHODS: Implant-constructs of each plate and CRIF were created using Canevasit rods as a bone substitute in an unstable gap fracture model. Six implant-constructs of each type were tested under single cycle four-point bending loading, and six were tested under single cycle torsional loading until permanent plastic deformation occurred. RESULTS: Torsional stiffness and yield load of the DCP were always significantly greater than the CRIF within the same group. Bending properties of the 2.0 DCP were not significantly different to the 2.0 CRIF. The 2.7 DCP had significantly higher bending values than the 2.7 CRIF. The bending stiffness of the 3.5 DCP and 4.5 DCP was significantly less than their CRIF counterparts. While the bending yield load of the 3.5 DCP was significantly greater than the 3.5 CRIF, the bending yield load of the 4.5 DCP was significantly less than the 4.5 CRIF. CONCLUSION: A weakness was found in the torsional resistance of the CRIF constructs compared to the DCP constructs. CLINICAL SIGNIFICANCE: Bone holding power and applied screw torque should be considered when using the CRIF system in clinical application.

Dowel pinning for feline metacarpal and metatarsal fractures.

The goal of this retrospective study was to describe dowel pinning, and to compare the results of osteosynthesis and external coaptation of metacarpal and metatarsal fractures in cats. Evaluation of the medical records of 351 cats yielded 63 cats treated with dowel pinning, 35 cats treated with external coaptation and 14 cats treated with both methods within the same limb. All of the cats had been re-evaluated at an average of 2.8 years (six months - 15 years) postoperatively. Dowel pinning was superior to external coaptation when all fractured bones of a limb could be pinned. When internal fixation of multiple fractures was not feasible in all fractured bones due to comminution or fragments that were too short to pin, the outcome was not significantly different from cases treated with external coaptation alone. Malunion was seen in 16% of fractured bones in cats treated with external coaptation and occurred secondary to implant bending in 3% of fractured bones treated with dowel pinning. The latter refers to one operated cat, which had four metacarpal fractures in the same limb. Radiographs taken at re-evaluation showed implant migration within the medullary canal in two cats, although neither showed any signs of non-union or lameness. Non-union was seen in one operated cat, in which the fracture (MC IV) could not be completely reduced with a K-wire. Osteomyelitis did not occur. Dowel pinning is an easy, inexpensive and effective technique for repair of metacarpal and metatarsal fractures in cats.

Transient benign osteopetrosis in a calf persistently infected with bovine virus diarrhoea virus.

A two-day-old Simmental calf was admitted suffering from a fracture of the right femur. The radiographs showed striking changes in all bones, evident as alter-noting zones of dense and less dense tissue (bone-in-bone) in the right femur and striped densities in the vertebral bodies. A stainless steel plate was used to repair the fracture, which healed well. The calf developed normally but was diagnosed as persistently infected with bovine virus diarrhoea (BVD) virus. It was kept in isolation and examined physically and radiographically during the following 13 months. The radiographic changes diminished during the first three months and at 13 months were barely visible. The animal was euthanatized, and immunohistochemistry revealed BVD virus antigen in numerous tissues. The radiographic abnormalities seen in this case are similar to those of the transient form of osteopetrosis in humans. Osteopetrosis in humans is currently thought to have a genetical cause, whereas it appears to be associated with viral disease in animals.

[CT myelography for diagnosis of brachial plexus avulsion in small animals]. / CT-Myelographie zur Diagnose des Plexus-brachialis-Abrisses beim Kleintier.

Avulsion of nerve roots of the brachial plexus can be diagnosed clinically, neurologically, radiographically and by electromyography. But like the myelography these techniques are inprecise for determination of the severity (partial or complete disruption) and the localization of the lesion. In human medicine the combination of computerized tomography with myelography shows high accuracy. Veterinary reports of experience in this field are not yet known. The aim of the present study was to demonstrate nerve root avulsions using myelography and computerized tomography. Three dogs and one cat with traumatic lesions of the brachial plexus were examined. The lesion could be seen in all patients. Thus CT-myelography results in an improved prognostic assessment of brachial plexus paralysis. Moreover, this technique could become one of the most important diagnostic methods for brachial plexus lesions involving nerve root reinsertion--neurotizations in veterinary medicine.

Long-term prognosis of metacarpal and metatarsal fractures in dogs. A retrospective analysis of medical histories in 100 re-evaluated patients.

OBJECTIVES: Lameness after metacarpal and metatarsal fractures in dogs is reported to occur with an incidence of 18% to 70%. On the basis of long-term results, the prognosis of these injuries was re-evaluated retrospectively. METHODS: Medical records of 100 dogs with complete clinical and radiographic follow-up examinations after an average of four years (4 months - 14 years) were evaluated. According to their treatment, patients were allocated to three groups (Group 1=conservative, Group 2=surgical, Group 3=combined). Assessment included complications during the healing period and the final radiographic and functional outcome, which was statistically compared for differences between groups (Fisher exact test, exact Wilcoxon-Mann-Whitney test). Further, risk factors for each bone were analyzed (stepwise, multiple logistic regression model). In 15 dogs, kinetic data (relative stance phase, peak vertical force and impulse) were investigated by computed gait analysis. RESULTS: Complications were observed in 11 of 67 (16%) conservatively, in three of 25 (12%) surgically, and in three of eight (37%) conservatively and surgically treated dogs. Overall frequency of lameness evaluated by visual clinical assessment was three percent. Frequency of osteoarthritis and nonunion was also low, accounting for three percent and one percent respectively, although healing of mainly single-bone fractures resulted in malunions in 14% radiographically. Synostoses were found in 19% of patients, and significantly more frequent in surgically treated dogs. A higher risk of complications was identified for metatarsal compared to metacarpal fractures. Further, an increased risk for complications was detected for a higher degree of displacement and instability. CLINICAL SIGNIFICANCE: According to the long-term results found in this study, the prognosis for metacarpal and metatarsal fractures is better than reported in the literature to date. With the reservation that more severe injuries are generally treated surgically, and these fractures more frequently developed synostosis, no significant difference could be detected between conservative and surgical treatment.

[Detection and evaluation of cartilage defects in the canine stifle joint - an ex vivo study using high-field magnetic resonance imaging]. / Ex-vivo-Untersuchungen zum Nachweis von Knorpeldefekten im Kniegelenk des Hundes mit der Hochfeld-Magnetresonanztomographie.

OBJECTIVE: The aim of our study was to implement and test an imaging protocol for the detection and evaluation of standardised cartilage defects using high-field magnetic resonance imaging (MRI) and to determine its limitations. MATERIAL AND METHOD: A total of 84 cartilage defects were created in the femoral condyles of euthanized dogs with a minimum body mass of 25 kg. The cartilage defects had a depth of 0.3 to 1.0 mm and a diameter of 1 to 5 mm. T1-FLASH-3D-WE-sequences with an isotropic voxel size of 0.5 x 0.5 x 0.5 mm and an anisotropic voxel size of 0.3 x 0.3 x 0.8 mm were used. In addition to quantitative evaluation of the cartilage defects, the sig- nal intensities, signal-to-noise ratios and contrast-to-noise ratios of the cartilage were determined. Of special interest were the limita- tions in identifying and delineating the standardised cartilage defects. RESULTS: With the anisotropic voxel size, more cartilage defects were detectable. Our results demonstrated that cartilage defects as small as 3.0 mm in diameter and 0.4 mm in depth were reliably detected using anisotropic settings. Cartilage defects below this size were not reliably detected. CONCLUSION AND CLINICAL RELEVANCE: We found that for optimal delineation of the joint cartilage and associated defects, a higher in-plane resolution with a larger slice thickness should be used, corresponding to the anisotropic settings employed in this study. For the delineation of larger cartilage defects, both the anisotropic and isotropic imaging methods can be used.

Uterine disorders in 59 rabbits.

The medical records of 59 rabbits with uterine disorders were assessed retrospectively. Ten animals were presented because of vaginal discharge; the reasons for presentation of the remaining 49 rabbits included mammary masses, skin tumours, anorexia and poor general health. All the rabbits underwent a clinical examination, and 54 were examined by ultrasonography and/or radiography. Forty-five rabbits underwent ovariohysterectomy and the other 14 rabbits were euthanased, three because of pulmonary metastases and 11 because of very poor health unrelated to their uterine disease. The genital tracts of all the rabbits were submitted for histological examination. Endometrial hyperplasia (in 24 rabbits) and adenocarcinoma (in 18 rabbits) were the most common uterine disorders; in a further 11 cases both conditions were observed. The remaining six rabbits had other uterine disorders. Four rabbits that were presented with adenocarcinoma of the mammary gland were found to have concurrent uterine disorders. The mean age of the rabbits with endometrial hyperplasia was 4.5 years, and that of the rabbits with adenocarcinoma was 6.1 years. Four rabbits had ovarian tumours.

Chondrogenesis, osteogenesis and adipogenesis of canine mesenchymal stem cells: a biochemical, morphological and ultrastructural study.

Musculoskeletal diseases with osteochondrotic articular cartilage defects, such as osteoarthritis, are an increasing problem for humans and companion animals which necessitates the development of novel and improved therapeutic strategies. Canine mesenchymal stem cells (cMSCs) offer significant promise as a multipotent source for cell-based therapies and could form the basis for the differentiation and cultivation of tissue grafts to replace damaged tissue. However, no comprehensive analysis has been undertaken to characterize the ultrastructure of in vitro differentiated cMSCs. The main goal of this paper was to focus on cMSCs and to analyse their differentiation capacity. To achieve this aim, bone marrow cMSCs from three canine patients were isolated, expanded in monolayer culture and characterized with respect to their ability for osteogenic, adipogenic and chondrogenic differentiation capacities. cMSCs showed proliferative potential and were capable of osteogenic, adipogenic and chondrogenic differentiation. cMSCs treated with the osteogenic induction medium differentiated into osteoblasts, produced typical bone matrix components, beta1-integrins and upregulated the osteogenic specific transcription factor Cbfa-1. cMSCs treated with the adipogenic induction medium showed typical adipocyte morphology, produced adiponectin, collagen type I and beta1-integrins, and upregulated the adipogenic specific transcription factor PPAR-gamma. cMSCs treated with the chondrogenic induction medium exhibited a round to oval shape, produced a cartilage-specific extracellular matrix, beta1-integrins and upregulated the chondrogenic specific transcription factor Sox9. These results demonstrate, at the biochemical, morphological and ultrastructural levels, the multipotency of cMSCs and thus highlight their potential therapeutic value for cell-based tissue engineering.

Calcium-excess causes subclinical changes of bone growth in Beagles but not in Foxhound-crossbred dogs, as measured in X-rays.

Numerous investigations and reports have covered the potential negative effects of an excess of calcium (Ca) in the skeletal development of young dogs. However, it still remains unclear why not all puppies, particularly of larger breeds, develop clinical signs of skeletal disorders after an overexposure to Ca. This trial with the small Beagle breed and a larger Foxhound-crossbred dog (with an adult weight of around 35 kg) investigated the effects of Ca-excess on parameters of bone growth. The employed small breed is known for its chondrodystrophic predispositions, no such data are reported for the slender hound-type Foxhound-crossbred dogs. The Ca-supply had no influence on weight development and general health of the dogs. The measurements of bone lengths and widths in X-rays of the forearm of Beagles and Foxhound-crossbred dogs at 6 weeks of age, and again after a period of overexposure to Ca at about 27 weeks of age, revealed a growth-reducing influence only in Beagles, without influence on clinical parameters of skeletal health.

[Surgical techniques in canine hip dysplasia]. / Operationsverfahren bei Hüftgelenkdysplasie.

Based on retrospective studies, the surgical techniques most commonly used in treating canine hip dysplasia are discussed. Total hip replacement provides the best functional results. Material fatigue is not a problem.

Changes in cardiopulmonary variables and platelet count during anesthesia for total hip replacement in dogs.

Changes in cardiopulmonary function and platelet count were determined in 22 dogs of various breeds that underwent total hip replacement with cemented femoral prostheses. In 11 dogs (group I) polymethylmethacrylate (PMMA) was inserted without venting the reamed and lavaged femoral canal. In a second group of 11 dogs (group II) a urethral catheter (ID: approximately 2.7 mm) was placed into the medullary cavity before the insertion of PMMA. The application of PMMA resulted in a decrease in end-tidal carbon dioxide tension (PETCO2) until 5 minutes after insertion of bone cement. Increases in arterial to end-tidal pCO2 gradient [P(a-ET)CO2] and physiological dead space (VD/VT) were recorded between 2 minutes before and 5 minutes after insertion of PMMA in 12 dogs. A significant decrease in platelet count occurred in both groups of dogs. Decreases in arterial pO2 (PaO2), arterial/alveolar oxygen tension ratio (PaO2/PAO2), and percent O2 saturation of hemoglobin in arterial blood (SaO2) were not statistically significant. No significant differences could be detected between data obtained from both groups of dogs. An increase in femoral intramedullary pressure caused by the insertion of PMMA and subsequent pulmonary microembolism by medullary contents has been considered the most likely cause for changes in pulmonary function. The lack of statistically significant differences in cardiopulmonary variables and platelet count between the two groups of dogs could have been related to inefficient pressure reduction by the method used.

[Gait analysis in dogs]. / Ganganalyse beim Hund. Teil 1: Dynamometrische und kinemetrische Messverfahren und ihre Anwendung beim Tetrapoden.

Gait analysis has found extensive application in human medicine in orthopaedics, rehabilitation and sports medicine. In veterinary medicine locomotor studies are focused on horses. The available dynamometric and kinemetric measurement systems and their application to tetrapods are discussed after a historical survey with literary review has been made. The installation of a gait analysis laboratory for small animals at the Department of Veterinary Surgery of the Ludwig-Maximilians-University of Munich and results of clinical studies including gait analysis will be presented.

[Minimal-flow anesthesia in the dog]. / Minimal-Flow-Narkose beim Hund.

Many veterinary practices possess an anesthetic machine with a rebreathing system, and therefore the facility to induce anesthesia under more cost-effective reduced fresh gas flow conditions in a semi-closed system. However, as the fresh gas flow is frequently far too high, the rebreathing element is used rarely or not at all, making the anesthesia unnecessarily expensive. The relationships between the fresh gas setting and the final concentrations of expired air are discussed, and experience in 53 dogs with minimal flow anesthesia (500 ml/min), an extreme variant of anesthesia induction using a semi-closed system with minimal excess gas volume and a high proportion of rebreathed gas, is described.

[Gait analysis in dogs. 2: Installation of a gait analysis laboratory and locomotion studies]. / Ganganalyse beim Hund. Teil 2: Aufbau eines Ganglabors und bewegungsanalytische Untersuchungen.

Following a review of the literature on dynamometric and kinemetric measurement systems in tetrapods (part 1, 19), the selection criteria and construction of a gait analysis laboratory for small animals at the Department of Veterinary Surgery of the Ludwig-Maximilians-University of Munich is described. The system consists of three units: a treadmill with integrated forceplates, a 3D-video motion analysis system, and dedicated computer and system software. The value of the equipment is demonstrated by means of results of clinical gait examinations (part 2). An advantage of the Munich system is that measurements of all four limbs on the treadmill can be repeated continuously and simultaneously.