2 research outputs found

    Mechanical testing of a steel-reinforced epoxy resin bar and clamp for external skeletal fixation of long-bone fractures in cats

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    <p>AIMS: To provide veterinarians with confidence when using a commercially available epoxy resin in external skeletal fixators (ESF), testing was conducted to determine exothermia during curing of the epoxy resin compared to polymethylmethacrylate (PMMA), the hardness of the epoxy resin as a bar over 16 weeks, and the strength of the epoxy resin bar compared with metal clamps in similarly constructed Type 1a ESF constructs simulating the repair of feline long bone fractures.</p> <p>METHODS: Exothermia of the epoxy resin during curing was tested against PMMA with surface temperatures recorded over the first 15 minutes of curing, using four samples of each product. The hardness of 90 identical epoxy resin bars was tested by subjecting them to cyclic loads (1,000 cycles of 20.5 N, every 7 days) over a 16-week period and impact testing 10 bars every 2 weeks. Ten bars that were not subjected to cyclic loads were impact tested at 0 weeks and another 10 at 16 weeks. Strength of the epoxy resin product, as a bar and clamp composite, was tested against metal SK and Kirschner-Ehmer (KE) clamps and bars in Type 1a, tied-in intramedullary pin, ESF constructs with either 90° or 75° pin placement, subjected to compressive and bending loads to 75 N.</p> <p>RESULTS: The maximum temperature during curing of the epoxy resin (min 39.8, max 43.0)°C was less than the PMMA (min 85.2, max 98.5)°C (p<0.001). There was no change in hardness of the epoxy resin bars over the 16 weeks of cyclic loading (p=0.58). There were no differences between the median strength of the epoxy resin, SK or KE ESF constructs in compression or bending when tested to 75 N (p>0.05). Stiffness of constructs with 75° pin placement was greater for SK than epoxy resin constructs in compression (p=0.046), and was greater for KE than epoxy resin constructs in bending (p=0.033).</p> <p>CONCLUSIONS: The epoxy resin tested was found to be less exothermic than PMMA; bars made from the epoxy resin showed durability over an expected fracture healing timeframe and had mechanical strength characteristics comparable to metal bar and clamp ESF constructs.</p> <p>CLINICAL RELEVANCE: The epoxy resin ESF construct tested in this study can be considered a suitable replacement for SK or KE ESF constructs in the treatment of feline long-bone fractures, in terms of mechanical strength.</p

    Surgical repair of humeral condylar fractures in New Zealand working farm dogs – long-term outcome and owner satisfaction

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    <div><p></p><p>AIM: To report the long-term outcome, return to work and owner satisfaction, for working farm dogs in New Zealand following surgical repair of humeral condylar fractures.</p><p>METHODS: A retrospective study of working dogs that had undergone surgical repair of one or more condylar fractures of the humerus was undertaken by searching the medical records of two referral veterinary clinics. The inclusion criteria were working dogs that had undergone open surgical reduction and internal fixation of a fracture of one or both humeral condyles. The ability of the dog to work after surgery, persistence of lameness and the owners' degree of satisfaction with the outcome were assessed from answers to a questionnaire.</p><p>RESULTS: Sixteen dogs met the inclusion criteria and had owner questionnaires completed at a median follow-up interval of 54 (min 3, max 121) months. Fifteen were working farm dogs (13 Heading dogs, including Border Collies, and two New Zealand Huntaways) and one dog was a cross-breed used for pig hunting. Four dogs had two fractures on separate occasions, of which three underwent surgery on both elbows at a median interval of 19 months. Of the 20 humeral fractures, 10 were lateral condylar, one was a medial condylar fracture and nine were dicondylar fractures. Of the 16 repairs with follow-up data, seven (44%) dogs could perform all expected duties following surgical repair, whilst a further eight (50%) could perform most duties although some allowances had to be made for some limitation of their performance. Of the 15 owners responding, 13 (87%) were satisfied or very satisfied with the outcome of surgery and felt the surgery was worth the expense. Post-operative complications requiring a second surgery occurred in 7/20 (35%) dogs, and all six dogs that received appropriate surgical revision returned to work.</p><p>CONCLUSIONS: In this small case series, surgical repair of humeral condylar fractures in working dogs had a good prognosis with 15/16 of treated dogs returning to full or substantial levels of work.</p><p>CLINICAL RELEVANCE: These data provide veterinarians with relevant information regarding the outcome and prognosis of surgery for clients whose working dogs have fractured a humeral condyle.</p></div
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