Defining a safe corridor for trans-iliac pin placement in cats.

OBJECTIVE: To identify whether a theoretical predictable safe corridor is available in cats for placement of trans-iliac pins without the use of fluoroscopy. METHODS: Twenty-one cats with straight orthogonal normal pelvic radiographs were included. Two start points were evaluated: a midpoint and a dorsal point. The midpoint was defined as midway between the dorsal lamina of the sacral vertebral canal and the cranial dorsal iliac spine. The dorsal start point was 2 mm ventral to the cranial dorsal iliac spine. The pin was assumed to be driven at 90 degrees to the lateral face of the ilium, and considered surgeon accuracy was ±4 degrees from the perpendicular. The angular range and the distance between the iliac wings from the ventrodorsal radiograph were used to calculate the possible cross-sectional area and pin exit location if driven from one iliac wing to the other. The corridor was then evaluated for repeatability in six randomly selected cats. RESULTS: Vertebral foramina penetration risk was identified in some cats when using a 1.6 and 2 mm-diameter pin using the mid-iliac wing start point. The dorsal start point decreased the available pin placement area but reduced the risk of entering the hazardous zone for all pin sizes up to 2 mm. CONCLUSION AND RELEVANCE: A theoretical defined safe corridor is available for trans-iliac pin placement in cats between 2.0 and 5.5 kg. A 1.2-mm pin is the safest if using the mid-iliac wing start point. A more dorsal start point can accommodate up to a 2.0-mm pin if correctly aligned to the sacrum.

Approaches to defining day-one competency: a framework for learning veterinary skills.

Competency at graduation, in a variety of physical and attitudinal skills, is an essential outcome measure for courses training veterinary surgeons. The approach adopted by the Royal Veterinary College, London, to identify and define the expected skill competencies required of our veterinary undergraduates by the time of graduation is described. In addition, we demonstrate how this skill set was built into a framework that was aligned with other student learning objectives. This two-year project resulted in the publication of a day-one skills handbook, which was introduced to the college staff and students in 2007.

The prevalence of canine patellar luxation in three centres. Clinical features and radiographic evidence of limb deviation.

The medical records of 155 dogs with patellar luxation (PL) from three different centres were analysed. Each case was classified according to the nature of its luxation and any concurrent orthopaedic conditions plus the age at diagnosis were also noted. Measurements relating to angle of inclination (AOI) of the femoral neck and medio-lateral bowing of the femur and tibia at the stifle were also recorded. The femoral and tibial data were compared to dogs with another orthopaedic condition in a case-control assessment. Labradors were most commonly affected (21%). Most luxations were medial (92%) and 54% of affected dogs were female. The mean AOI of the hip was 148.95 degrees . There was a statistically significant difference between the stifles of dogs with PL compared to a control population. This study concluded that PL in large breeds is increasing. Lateral luxation was uncommon and was not associated exclusively with large breeds. Females were more likely to have PL than males and being female was a risk factor associated with coxa valga. There are significant differences in medio-lateral stifle conformation between dogs with PL and control dogs.

Epoxy putty external skeletal fixation for fractures of the four main metacarpal and metatarsal bones in cats and dogs.

The objective of this retrospective study was to report the clinical use, advantages, disadvantages, complications and outcome of an epoxy putty external skeletal fixator (EPESF) used for the repair of fractures of all four main metatarsal or metacarpal bones in a single limb in 11 dogs and 11 cats. The aim of this technique was to achieve satisfactory alignment of the proximal and distal joints and the digits, rather than anatomical reconstruction of the metacarpal/metatarsal bones themselves. All of the cases achieved fracture union and they all recovered fully without any residual lameness.

Effect of passive stretching on the range of motion of osteoarthritic joints in 10 labrador retrievers.

Ten labrador retrievers and their owners undertook a programme to determine the effect of passive stretching on the dogs' osteoarthritic joints, which had a restricted range of motion. The range of motion of the joints was measured before and after the 21-day study, during which the owners performed 10 passive stretches for a hold of 10 seconds twice daily. Goniometric measurements showed that the passive stretching had significantly increased the range of motion of the joints.

Digital analysis of ulnar trochlear notch sclerosis in Labrador retrievers.

OBJECTIVES: To compare ulnar trochlear notch bone radiopacity in Labrador retrievers with and without fragmented medial coronoid process using quantitative analysis of film density on digitised radiographs. METHODS: Mediolateral view elbow radiographs from Labrador retrievers (n=34) aged between six and 18 months were obtained and digitised. Images from dogs with an arthroscopic diagnosis of fragmentation of the medial coronoid process (n=17) were compared with that of a control population (n=17), and this data subject to statistical analysis. RESULTS: A statistically significant relationship between the presence of increased trochlear notch radiopacity and a fragmented medial coronoid process was identified. Fractional analysis of this area shows the region of greatest difference in radiopacity between normal and fragmented medial coronoid process cohorts to be in the trochlear region of the medial coronoid process of the ulna. A decrease in radiopacity values in the dysplastic group versus the normal cohort was observed for the region of the proximo-caudal ulnar trochlear notch. CLINICAL SIGNIFICANCE: An increase in ulnar trochlear notch radiopacity is a finding associated with fragmentation of the medial coronoid process in Labrador retrievers.

Comparison of anatomical tibial plateau angle versus observer measurement from lateral radiographs in dogs.

This study was conducted to compare the anatomical tibial plateau angle (TPA) with that measured by observers from a lateral radiograph of the limb, the hypothesis being that there would not be any statistically significant differences between the observer measured TPA and the true anatomical TPA. Twelve pelvic limbs from skeletally mature greyhound cadavers, without any clinical or radiographic evidence of stifle pathology, were used in this study. The radiographs were taken of each limb in a lateral position with the primary beam centered over the tibial eminences and collimated to include the stifle and tarso-crural joints. For subsequent radiographs, Kirschner wires were inserted to enable identification of the tibial plateau. The TPA was then measured, by three observers, from the plain radiographs and by one observer from the marked radiographs. The mean observer TPA was 24.4 degrees (range 17-30 degrees) and the mean anatomical TPA was 23.8 degrees (range 15-31 degrees). The mean and median discrepancy between the anatomical TPA and the observer TPA was negative and very small (- 0.64 degrees and 0 degrees). The magnitude of the discrepancy between individual measurements made by the observers tended to overestimate small angles and underestimate the large ones, and this trend is statistically significant. These results suggest that the measurements made by observers accurately represent the anatomical slope of the tibial plateau. Therefore, observer TPA is suitable for the planning and assessment of TPLO procedures. However, as the anatomical TPA moves away from a median angle (23.25 degrees) the magnitude of error in the measurement increases.

Direct transformation from quiescence to bone formation in the adult periosteum following a single brief period of bone loading.

The concept of resorption preceding formation in a coupled response is well established as the normal sequence of remodeling in adult bone. So prevalent is this concept, however, that the idea of the direct activation of osteogenic modeling in normal adult bone is often ignored. This experiment documents the direct transformation of the normal, quiescent, adult periosteum to active bone formation. The osteogenic stimulus was provided by a single short period of dynamic loading. Periosteal activation and the production of new bone within 5 days of loading was unaccompanied by resorption or the presence of osteoclasts. We therefore conclude that an adult resting periosteum can become directly converted to formation as a physiologic response to an appropriate osteogenic stimulus without the need for resorption. To distinguish this process from remodeling we suggest it be called renewed modeling. It is notable that a single short exposure to an "osteogenic" loading regime can influence the full cascade of cellular events between quiescence and active bone formation.

Early loading-related changes in the activity of glucose 6-phosphate dehydrogenase and alkaline phosphatase in osteocytes and periosteal osteoblasts in rat fibulae in vivo.

The tibiae and fibulae of 14-week-old rats were subjected to a single 5 minutes period of cyclic longitudinal loading at 1 Hz. The activity of the enzymes glucose 6-phosphate dehydrogenase (G6PD) and alkaline phosphatase (ALP) in osteocytes and periosteal osteoblasts was measured immediately and 24 h after loading. In osteocytes G6PD activity was increased immediately after loading but returned to control values 24 h later. There was no detectable ALP activity in these cells regardless of loading history. In periosteal osteoblasts G6PD activity was raised immediately after loading and remained higher than controls 24 h later. ALP activity in periosteal cells was unaffected immediately after loading but 24 h later was substantially increased. These findings are consistent with osteocytes and periosteal cells both being immediately responsive to periods of intermittent loading in their adjacent matrices. In both cell types an early feature of this response is an increase in G6PD activity. In osteocytes this response is short-lived, suggesting that it is an early biochemical change associated with strain perception that does not progress to matrix synthesis. The increase in G6PD activity with unaffected ALP levels in periosteal cells immediately after loading is consistent with a similar response. In these cells the increase in G6PD accompanied by increased ALP levels 24 h after loading suggests that the loading-related response progresses to new bone formation.

Early strain-related changes in cultured embryonic chick tibiotarsi parallel those associated with adaptive modeling in vivo.

A model was developed for the application of cyclic mechanical loads to 17 day embryonic chick tibiotarsi in culture. A single 20 minute period of intermittent loading at 0.4 Hz, producing physiologic peak strains and strain rates, resulted in two peak strain magnitude-related responses that were previously reported in vivo: (1) a rapid increase in glucose 6-phosphate dehydrogenase activity in osteoblasts and osteocytes and (2) increased RNA synthesis, as shown by increased incorporation of [3H]uridine into extracted RNA. The RNA response was detectable 8 h following loading but was more pronounced by 24 h. Both responses were blocked by indomethacin (10(-6) M). These results demonstrate that embryonic chick bones in organ culture exhibit cellular responses to loading similar to those previously identified in adult canine cancellous bone cultures in vitro and adult avian cortical bone in vivo. These findings are consistent with a sequence of events between loading and new bone formation that includes an immediate strain magnitude-related, prostanoid-dependent increase in activity of the pentose monophosphate shunt in osteoblasts and osteocytes, followed by a similarly strain magnitude-related increase in RNA synthesis over the subsequent 24 h.

Modulation of bone loss during disuse by pulsed electromagnetic fields.

The effect of pulsed electromagnetic fields (PEMFs) on bone loss associated with disuse was investigated by applying 1.5 Hz repetitions of 30 ms bursts of asymmetric pulses, varying from +2.5 to -135 mV, to bones deprived of their normal functional loading. The proximal portion of one fibula in each of a group of ovariectomised adult female beagle dogs was isolated from functional loading in vivo by proximal and distal osteotomies. Comparison of these prepared bones with their intact contralateral controls after 12 weeks, showed a 23% reduction in cross-sectional area. In similarly prepared bones exposed to PEMFs for 1 h per day, 5 days per week, this bone loss was substantially and significantly reduced to 9% (p = 0.029). There was no evidence of any new bone formation on the periosteal surface of prepared fibulae in treated or untreated situations. PEMF treatment was not associated with any significant change in number of osteons per mm2 formed within the cortex of the bones, their radial closure rate, or their degree of closure. The modulation in loss of bone area associated with exposure to PEMFs can, therefore, be inferred to be due to a reduction in resorption on the bone surface.

Comparison and assessment of casting materials for use in small animals.

This paper describes an investigation to evaluate the properties and uses of the different casting materials available for small animals. After a consideration of the properties that make an 'ideal cast', clinically relevant tests were performed on tubular casts of the various products. No single product demonstrated consistent superiority by all the criteria. All the products tested can be useful in a variety of situations, and suggestions for their uses are set out.

Use of the bisphosphonate drug alendronate for palliative management of osteosarcoma in two dogs.

The bisphosphonate drug alendronate was used to suppress bone remodelling and tumour osteolysis as a palliative treatment for two dogs with osteosarcoma, one of the tibia and one of the maxilla. A spiral fracture associated with the tibial tumour healed after it was stabilised with an external skeletal fixator. Both dogs remained comfortable and survived for 12 and 10 months respectively after diagnosis, despite the fact that neither primary tumour was resected.

Clinical efficacy and pharmacokinetics of carprofen in the treatment of dogs with osteoarthritis.

Six medium to large breed dogs with osteoarthritis were treated with 2 mg/kg of racemic carprofen, mixed with their morning feed, daily for 28 days. The treatment significantly (P < 0.01) reduced their mean lameness score, measured on a visual analogue scale, and there was a trend (P = 0.11) for the peak vertical forces exerted on a forceplate to be increased in the most severely affected limb. The plasma concentration-time relationships of the S(+) and R(-) enantiomers were studied for 24 hours after the first dose and after seven days and 28 days. There were no significant differences between the mean pharmacokinetic parameters measured on the three occasions, suggesting that carprofen was not accumulated and that tolerance to the drug did not develop. Although the pharmacokinetic parameters of the S(+) and R(-) enantiomers were generally very similar, there were wide variations both between and within dogs.

Methicillin-resistant Staphylococcus aureus infections in 11 dogs.

Methicillin-resistant Staphylococcus aureus infection was identified in 11 dogs. The infection was associated with surgical treatment especially orthopaedic surgery. Infection after traumatic wounding, and recurrent pyoderma was also seen. Oral antibiotic treatment improved or resolved the infection in nine of the 11 dogs, although the methicillin-resistant isolates were susceptible to relatively few antibiotics.

Haemangiosarcoma of the scapula in three dogs.

Three cases of haemanglosarcoma in the scapula of the dog are reported. Two cases were euthanased soon after diagnosis, due to the presence of metastases, while the third was treated surgically and recovered well. However, seven months after surgery, this dog was re-presented with a cervical spinal problem which was presumed to be a metastatic lesion.

Pathological fracture of the femur secondary to haematogenous osteomyelitis in a weimaraner.

A seven-year-old male weimaraner developed an acute-onset non-weightbearing pelvic limb lameness without a history of significant trauma. Radiographs demonstrated an oblique fracture of the femur associated with a lytic bone lesion, while cytology and histopathology of the lesion were consistent with osteomyelitis. A pure growth of Streptococcus intermedius was obtained from culture of affected tissue samples. The fracture healed without complication after rigid internal fixation and antibiotic therapy.

Management of antebrachial deformity and shortening secondary to a synostosis in a dog.

A nine-week-old labrador was presented with a deformed left forelimb causing obvious lameness. Radiographs suggested that the dog had suffered a fracture involving the radius and ulna which had healed resulting in a synostosis. There was a concurrent radial physeal injury. The dog was treated initially by osteotomy of the radius and ulna stabilised using a static external skeletal fixator. At a subsequent surgery lengthening of the limb was achieved by using an Ilizarov apparatus. Worsening carpal hyperflexion was managed by bandaging in forced extension. A successful outcome was achieved with a final result of a 24 per cent discrepancy in length between the two radii at 17 months of age. An increase in length of the ipsilateral humerus was seen in association with the shortened forelimb.

Comparison of two surgical techniques for the management of cervical spondylomyelopathy in dobermanns.

A study was undertaken to compare the efficacy of two surgical techniques for the treatment of caudal cervical spondylomyelopathy (CCSM): ventral decompression (slot) and vertebral distraction and stabilisation with a screw and washer (screw/washer). Twenty-eight dobermanns managed surgically for disc-associated CCSM during a four-year period were studied retrospectively. The maximum postoperative period was 40 months. Cases were excluded if a minimum follow-up of 24 months after surgery could not be made. A 'slot' took a longer time to perform and had a higher rate of immediate postoperative deterioration. Duration of hospital stay was similar for both procedures. At six months after surgery the two techniques were comparable; 12/14 (screw/washer) and 13/14 (slot) patients were deemed to have a satisfactory outcome. Recurrence of cervical spinal cord disease was higher in the screw/washer dogs. At one year after surgery the recurrence rate was zero (slot) and 5/14 (screw/washer), respectively. At two years after surgery 4/14 of the slot dogs had deteriorated compared to 7/14 of the screw/washer dogs. Where investigated, the cause of deterioration was either a domino disc lesion or vertebral endplate collapse and dorsal displacement of the screw and washer.

Clinical veterinary students' perceptions of a 'Day one' skills guide.

Veterinary schools in the UK are required by the Royal College of Veterinary Surgeons to ensure that their students have attained essential 'Day one' skills (DOS) by graduation. To aid students' understanding of how they could satisfy this requirement, the Royal Veterinary College produced a DOS guide, which was distributed in the 2007 to 2008 academic year to students in the third and fourth years of the professional veterinary course. The same students were surveyed towards the end of the 2008 to 2009 session about the guide, when they were in the fourth and final years, to rate its usefulness and to indicate their perceived levels of competence, both currently and expected at graduation. Focus group discussions were subsequently conducted to explore the findings of the survey. Responses from 88 fourth-year (39 per cent) and 174 (87 per cent) final-year students revealed that while almost all respondents were aware of the DOS guide, their use of it was low. Final-year students rated themselves as being more competent than fourth-year students, but were less optimistic about their expected level of competence regarding several invasive procedures, which some students considered to be 'unattainable' by graduation, despite the apparent value of extramural studies and intramural rotations in providing opportunities for learning.