竹材Ⅲ型层间的断裂韧性

采用改进设计的端部切口悬臂梁(SCB)装置,试验测试毛竹(Phyllostachs pubescens)Ⅲ型层间断裂性质,并分别用柔度法和面积法计算其Ⅲ型层间断裂韧性值。结果表明:(1)采用柔度法和面积法得到的Ⅲ型层间断裂韧性,分别为2.38 N·m~(-1)(标准差0.74 N·m~(-1))、2.20 N·m~(-1)(标准差0.36 N·m~(-1)),前者略高于后者,但方差分析差异不显著;(2)二种方法测得的Ⅲ型层间断裂韧性,基本上与裂纹尺寸无关,说明层间断裂韧性是竹材的一种基本性质;(3)对竹材断面的观察发现,Ⅲ型层间裂纹在未木质化的短型基本组织细胞中的扩展是伴随着胞壁的撕裂,但在已木质化的长型基本组织细胞之间和纤维束之间,裂纹是沿胞间层扩展的。     

石膏-微米厚度刨花腕部骨伤固定夹板的制造工艺

骨伤科固定材料研究的一直是骨伤科中最基本和最活跃的领域。从最初的手制夹板到石膏绷带、热塑夹板、高分子绷带等材料的发明与应用,都在骨伤科固定性能上有了长足的进步,给骨伤科的救治带来了更加有效的手段和方法。本研究开发一种新型医用材料石膏-微米厚度刨花腕部骨伤固定夹板。石膏-微米厚度刨花腕部     

Computed tomography of proximal metatarsal and concurrent third tarsal bone fractures in a Thoroughbred racehorse

A 2‐year‐old Thoroughbred filly presented to the William R. Pritchard Veterinary Medical Teaching Hospital at the University of California at Davis for whole body nuclear scintigraphic evaluation after an acute onset of nonweightbearing right hindlimb lameness post race. The use of computed tomography (CT) enabled visualisation of additional pathology that was not initially appreciable using combined imaging modalities of nuclear scintigraphy and digital radiography, which ultimately altered the selected course of treatment. Computed tomography in horses with fractures of the cuboidal bones of the hock can provide valuable additional information regarding fracture configuration and radiographically occult pathology, which may help to guide clinical decisions about treatment.     

Purulent Necrotic Dislocation of the Hip Joint Associated with Umbilical Infection in a Foal

A 42-day-old heavy draft horse fell into sudden astasia. Significant swelling and heat sensation of the left femoral region were observed. Because of a friction sound in the left hip, we supposed that the hip joint was dislocated or the hip bone was fractured. Computed Tomography (CT) examination showed that the left hip joint was dislocated and the left femoral head was disjunct. We carried out a pathological autopsy, and made a diagnosis of the foal as fracture of the hip bone and femoral head with suppurative umbilical arteritis. Pathologic changes in the umbilical artery and hind leg were completely unilateral, suggesting that left umbilical arteritis spread to the blood circulation, causing arthritis and dislocation of the hip bone.     

Patterns of scintigraphic uptake in the fetlock joint of Thoroughbred racehorses and the effect of increased radiopharmaceutical uptake in the distal metacarpal/tarsal condyle on performance

Reasons for performing study: The effect of palmar osteochondral disease lesions on performance of Thoroughbred (TB) racehorses is unclear. There is a need to describe patterns of radiopharmaceutical uptake (IRU) in fetlock joints of TB racehorses and to evaluate post scintigraphy performance. Hypotheses: IRU in the metacarpal (MC) and metatarsal (MT) condyles is more common than IRU in the parasagittal grooves and is associated with poorer post diagnosis performance than controls. Methods: Location of IRU within the fetlock region was identified and graded subjectively in TB racehorses. Performance variables were determined from race records for horses with moderate/marked MC/MT condylar IRU (cases), other horses undergoing scintigraphy (scintigraphy controls) and age/sex matched controls from the last race in which a case participated (controls). Statistical analyses included quantile regression, Fisher's exact test, Kaplan‐Meier survival curves, log‐rank test and Cox regression. Results: Metacarpal/MT condylar IRU was identified in 103/220 horses with only 3/220 having parasagittal IRU. Moderate/marked IRU was identified in the MC and MT condylar regions in 62 and 39 horses, respectively, with palmaromedial and plantarolateral IRU most common. Fore‐ and hindlimb cases had fewer starts, reduced earnings (P<0.001) and reduced earnings/start than controls respectively. Cases were more likely to return to racing later than controls following a rest period. Cases were older than scintigraphy controls. Conclusions: In TB racehorses presenting for lameness MC/MT condylar IRU is the most common abnormality identified within the fetlock joint. Racehorses with moderate/marked condylar IRU have a shortened racing career, are less successful than age/sex matched controls and are older than other racehorses presented for scintigraphy. Potential relevance: Overload of the MC/MT condyles is a common and significant problem in TB racehorses that is readily identified with scintigraphy. Scintigraphy of horses that are lame or performing poorly is less useful for screening for potential condylar fractures.     

The use of small (2.7 mm) screws for arthroscopically guided repair of carpal chip fractures

Reasons for performing the study: Removal of large chip fractures of the carpal bones and the osteochondral deficits that result, have been associated with a worse prognosis than removal of small fragments in similar locations. Hypothesis: Reducing the articular defects by repair of large osteochondral fragments may have advantages over removal. Methods: Horses with osteochondral chip fractures that were of sufficient size and infrastructure to be repaired with small (2.7 mm diameter) AO/ASIF cortex screws were identified and repair effected by arthroscopically guided internal fixation. Results: Thirty‐three horses underwent surgery to repair 35 fractures of the dorsodistal radial carpal bone (n = 25), the dorsal margin of the radial facet of the third carpal bone (n = 9) and the intermediate facet of the distal radius (n = 1). There were no surgical complications and fractures healed satisfactorily in 26 of 28 horses and 23 horses returned to racing performance. Conclusion: Arthroscopically guided repair of carpal chip fractures with small diameter cortex screws is technically feasible and experiences with 33 cases suggest that this may have advantages over fragment removal in managing such cases. Potential relevance: Surgeons treating horses with large chip fractures of the carpal bones should consider arthroscopically guided internal fixation as an alternative to removal.     

刺槐根系抗弯特性研究

从根径和坡位两方面研究了石质陡边坡刺槐根系的抗弯特性。通过对刺槐根系进行室内单根弯曲试验,分析了不同坡位下坡向侧根的抗弯特性。试验结果表明,根系的抗弯强度与坡位的关系显著,不同坡位抗弯强度关系为:坡顶>坡中>坡底。坡顶和坡底根系的抗弯强度与根径之间存在递增的幂函数关系,而坡中根系抗弯强度与根径之间的关系不显著。弯曲弹性模量与根径存在递减的幂函数关系,在根径大于8mm左右,不同坡位根系弯曲弹性模量大小关系为:坡顶>坡中>坡底。不同坡位根系的最大弯曲力之间差异不显著,最大弯曲力沿着坡面向下呈递减趋势。不同坡位根系的断裂挠度之间差异也不显著,但根系的断裂挠度沿着坡面向下呈递增趋势。综合这些结果,可以发现坡顶根系的抗弯性能最佳,对边坡稳定的贡献较大。     

纤维蛋白胶复合物促进犬骨折愈合的临床学观察

为了探索纤维蛋白胶(FG)联合人骨形态发生蛋白(rhBMP-2)、碱性成纤维细胞生长因子(bFGF)和妥布霉素的复合物对犬骨折愈合的影响,建立了犬胫骨骨折模型,将FG复合物应用于实验组和空白对照组的胫骨骨折处,在术后2、4、8、12、16周,测定骨折处周围软组织充血水肿消除时间、利用X射线影像学评价骨折愈合程度、测定骨折愈合部位的骨密度(BMD)及骨密度比率、骨痂体积,测定胫骨生物力学强度并进行统计和分析。实验组和对照组比较:术部红、肿、热消失时间显著缩短,术后各时间点的X射线影像学评分更高,术后各时间点骨痂更大,术后16周术部骨骼能承受的最大载荷和最大位移显著增大。结果表明FG联合rhBMP-2、bFGF与妥布霉素应用于骨折部位,可促进骨折愈合过程中软组织的生成,缩短骨折愈合的时间,提高骨生物力学强度。     

Use of rotational periosteal flaps in primary repair of sinofacial fractures in seven horses

ABSTRACT

Case history: Medical records were reviewed of horses (n?=?7) undergoing surgery for fracture of one or more facial bones extending into the paranasal sinuses that was repaired primarily within 24 hours of the time of injury using a rotational periosteal flap, between April 2009 and May 2017. A kick from another horse was the cause of the injury of three horses, and one horse was injured when it collided with a tree. The cause of the injury of three horses was unknown.

Clinical findings and treatment: Fractures were of the right maxillary bone in two horses, the left maxillary bone in two horses, the left frontal and left nasal bones in two horses, and the right frontal bones in one horse. The fracture of all but one horse was accompanied by an open wound. The fracture of all seven horses was reduced, stabilised, and covered with a rotational, periosteal flap. Surgery was carried out while standing in six horses, and while anesthetised in one horse. All horses had a deficit in the fractured facial bones after the fracture was reduced. Four horses had complications following surgery, but all horses were reported to have excellent cosmetic outcomes and had retuned to their previous level of activity, as reported by their owners.

Clinical relevance: Covering a primarily repaired sinofacial fracture of a horse with a rotational periosteal flap resulted in good cosmetic outcomes, and may be especially beneficial if the fracture is accompanied by loss of bone.