S. Carmichael

Prevalence of radiographic signs of degenerative joint disease in a hospital population of cats.

The prevalence of radiographic signs of degenerative joint disease (including appendicular osteoarthritis) among a hospital population of 218 cats was 33·9 per cent (74 cats), and the prevalence of signs of appendicular joint osteoarthritis was 16·5 per cent (36 cats). Half of the cases of appendicular joint osteoarthritis had no apparent radiographic or historical cause, and clinical signs of lameness were recorded in only six of them, all of which had an apparent radiographic cause. The 74 cats with radiographic signs of degenerative joint disease were on average significantly older than the 144 cats in which there were no radiographic signs of the disease.

Antimicrobial-resistance trends in bacterial isolates from companion-animal community practice in the UK.

We conducted a longitudinal, retrospective investigation of antimicrobial resistance in bacterial isolates obtained from canine and feline clinical cases in veterinary community practice in UK (1989-1997). Individual-drug resistance was examined using isolates of Escherichia coli and Staphylococcus spp. as Gram-negative and Gram-positive indicator organisms, respectively. The annual prevalence of resistance was calculated for each organism to each of nine (for E. coli) and 11 (for Staphylococcus spp.) selected antimicrobials. The annual prevalence of multiple-drug resistance (MDR) was calculated for E. coli, Proteus spp., Pseudomonas spp., staphylococci and streptococci. Using a chi-square test for trend, significant rising trends were identified in individual resistance of E. coli to clavulanate-amoxycillin and streptomycin, and in MDR of E. coli, Proteus spp. and Pseudomonas spp. Declining trends were identified in individual resistance of Staphylococcus spp. to ampicillin and penicillin. Comparison with previously reported results from a contemporaneous investigation of companion-animal hospital patients indicated that selection pressures acting on the two populations overlapped but were not identical.

Kinematic analysis of the gait of 10 labrador retrievers during treadmill locomotion

The trotting gait of 10 sound, adult labrador retrievers was analysed using kinematic gait analysis on a purpose-built treadmill using video-based motion analysis software. The maximal angular displacement, minimal angular displacement, average angular displacement, and the maximal positive and negative angular velocities of the right elbow and right stifle were measured over five gait cycles at defined time points during each of five two-minute sessions. The dogs’ trotting gait was not repeatable, either for individual dogs during the first session or between sessions, or between dogs at the same time points during a session.

A review of osteoarthritis and obesity: current understanding of the relationship and benefit of obesity treatment and prevention in the dog

Obesity is an increasingly important health problem for both man and dog. Osteoarthritis (OA) is a significant cause of pain and disability in both species. A link between obesity and OA has been established in man, though the exact mechanism of the relationship remains to be fully elucidated - current research supports both biomechanical and biochemical theories. There is good evidence (class I*) to support weight loss as an effective treatment for human knee OA. In the dog, the relationship is just beginning to be investigated. The results of one study in dogs (class IV evidence*) suggest that preventing the development of overweightness and obesity reduces the prevalence of hip dysplasia and OA of the hip and other joints. Three other studies (class III and IV evidence*) support weight loss as an effective treatment for OA in affected overweight and obese dogs. Further research could yield greater understanding of the pathophysiology of this relationship, perhaps identifying novel therapeutic targets. Confirmation and better understanding of the positive effect of treating and preventing obesity on symptoms and prevalence of OA is likely to be valuable in the campaign against canine obesity.

Trends of antimicrobial resistance in bacterial isolates from a small animal referral hospital

A longitudinal, retrospective investigation was made of antimicrobial resistance in bacterial isolates obtained from clinical cases in a small animal hospital between 1989 and 1997. Isolates of Escherichia coli and Staphylococcus species were used as Gram-negative and Gram-positive indicator organisms, respectively, and the annual prevalence of antimicrobial resistance was calculated for each organism to each of nine (for E coli) and 11 (for Staphylococcus species) appropriate antimicrobials, including enrofloxacin. Using a chi-square test for trend, statistically significant, rising trends were identified in the resistance of E coli to amoxycillin (P=0.04), clavulanate-amoxycillin (P<0.01) and streptomycin (P<0.01), and in the resistance of Staphylococcus species to erythromycin (P<0.01). There was an equivocal, rising trend for the resistance of Staphylococcus species to cephalexin. No significant trends were apparent for any of the other 15 organism/drug interactions. The annual prevalence of multiple drug resistance was calculated for E coli, Proteus species, Pseudomonas species, staphylococci and streptococci, but no statistically significant trends were identified.

Retrospective evaluation of the long-term outcome of non-surgical management of 74 dogs with clinical hip dysplasia

The long-term outcome for dogs treated non-surgically for clinical signs of canine hip dysplasia were evaluated retrospectively; 74 dogs were evaluated by a postal questionnaire sent to their owners, and 24 of these were also evaluated by a veterinary clinical examination. A total of 11 outcome variables were evaluated. Depending on the variable assessed, between 31 (41·9 per cent) and 49 (66·2 per cent) of the dogs remained clinically affected according to their owners assessment, and between 17 (70·8 per cent) and 23 (95·8 per cent) of the 24 dogs had abnormalities attributed to hip osteoarthritis according to the veterinary assessment. Orthopaedic abnormalities other than hip dysplasia affected 17 of the 24 dogs. Long-term medications had been prescribed for the treatment of clinical signs associated with hip dysplasia in 41 of the 74 dogs.

Retrospective study of Achilles mechanism disruption in 45 dogs.

Forty-five cases of canine Achilles mechanism disruption were reviewed, mostly involving medium-sized dogs, among which dobermanns, labradors and border collies were most commonly represented. Most cases were acute in onset (66.7 per cent), and were usually closed injuries (75.6 per cent). In the majority of cases, the damage involved all tendons (26.7 per cent), all tendons except the superficial digital flexor tendon (22.2 per cent), or the gastrocnemius alone (20 per cent). Damage most commonly occurred at the tendo-osseous junction (60 per cent), with injury occurring less commonly at the musculotendinous junction (20 per cent) or in the body of the tendon (13.3 per cent). A plantigrade posture was not predictive of involvement of specific tendons, but was more likely if the injury involved the musculotendinous junction. The most common method of treatment was a primary tendon repair using polydioxanone suture in a locking-loop pattern, with placement of a temporary calcaneotibial screw and cast. The outcome was not significantly influenced by whether the injury was open or closed, the duration of the injury, the tendons involved, or the method of repair. Complications were recorded in 16 cases (35 per cent), of which 10 were minor and six major. Complications were significantly more likely if the damage involved the body of the tendon. Long-term follow-up was available for 19 dogs; the outcome of surgery was considered to be good to excellent in 18 dogs.

Value of direct smears of synovial fluid in the diagnosis of canine joint disease

Assessments of direct smears of synovial fluid by four clinicians were compared with the results obtained with a Coulter counter. Estimates of total white cell counts by the clinicians were inaccurate and generally higher than the Coulter counter results. The method had a low sensitivity and specificity for the identification of degenerative joint disease and normal joints in comparison with the identification of inflammatory joint disease. There were marked variations in the results obtained by the four clinidans for all the analyses in the study.

The role of computed tomography in the classification and management of pelvic fractures

Computed tomography (CT) imaging is an important component in the pre-operative assessment of pelvic fractures in humans. The value of CT images in the management of small animal pelvic fractures is presently undetermined. The objective of this study was to investigate the benefits of CT images on the management of pelvic fractures. A prospective study of 25 traumatised cases of canine and feline pelvic fractures were evaluated, where CT images and conventional orthogonal radiographic assessments were performed on each case. Three diplomat orthopaedic surgeons independently reviewed the radiographs and CT images on separate occasions and determined fracture classification, management plan, estimated recovery time and prognosis. A consensus review of the imaging modalities and surgical reports was used as the definitive fracture description. For all observers, management was not found to differ significantly between radiographic and CT analysis (P< 0.05). There was moderate agreement between observers and between imaging modalities for fracture description. Greatest discrepancy was found as the fracture complexity increased, such as with acetabula and sacral fractures, whereby CT was the most sensitive. Clinically high quality radiography would be recommended for all pelvic fracture cases; CT may be beneficial where there is uncertainty, particularly with acetabula fractures or sacral fractures causing neurological deficits. Experienced orthopaedic surgeons often disagreed on the diagnosis, treatment and prognosis of pelvic trauma.

FURTHER STUDIES OF THE CENTRAL NERVOUS SYSTEM IN CANINE GIANT AXONAL NEUROPATHY

Griffiths I.R., Duncan I.D., McCulloch M. & Carmichael S. (1980) Neuropathology and Applied Neurobiology 6, 421–432