Blikslager A T, Bowman K F, Abrams C F, Seaboch T R, Hunt E L
Department of Food Animal and Equine Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606.
Am J Vet Res. 1994 Mar;55(3):415-8.
Holding power was determined for various orthopedic screws in bones of calves. Holding power was defined as maximal tensile force required to remove a screw divided by thickness of bone engaged by the screw (kN/mm). Comparative pull-out tests were performed, using pairs of large metacarpal or metatarsal bones from calves aged 3 to 14 days. Comparisons were made of the holding power of 6.5-mm fully threaded cancellous screws and 5.5-mm cortical screws in the proximal and distal metaphyses, and of 4.5-mm and 5.5-mm cortical screws in the diaphysis. Sixteen repetitions of each comparative trial were performed. There was no statistically significant difference in the holding power of 4.5- and 5.5-mm cortical screws in the diaphysis. There was no significant difference in the holding power of 5.5-mm cortical and 6.5-mm fully threaded cancellous screws in the proximal metaphysis. In the distal metaphysis, 6.5-mm fully threaded cancellous screws had significantly (P < 0.001) greater holding power than did 5.5-mm cortical screws. There was no significant difference between the mean holding power of 5.5-mm cortical screws in the proximal metaphysis and 5.5-mm cortical screws in the distal metaphysis. There was significantly (P < 0.01) greater mean holding power of 6.5-mm cortical, fully threaded cancellous screws in the distal metaphysis, compared with the proximal metaphysis.
对小牛骨骼中的各种骨科螺钉进行了把持力测定。把持力定义为取出螺钉所需的最大拉力除以螺钉所嵌入的骨厚度（kN/mm）。使用3至14日龄小牛的成对大掌骨或跖骨进行了比较拔出试验。比较了6.5毫米全螺纹松质骨螺钉和5.5毫米皮质骨螺钉在干骺端近端和远端的把持力，以及4.5毫米和5.5毫米皮质骨螺钉在骨干中的把持力。每个比较试验重复进行16次。4.5毫米和5.5毫米皮质骨螺钉在骨干中的把持力无统计学显著差异。5.5毫米皮质骨螺钉和6.5毫米全螺纹松质骨螺钉在干骺端近端的把持力无显著差异。在干骺端远端，6.5毫米全螺纹松质骨螺钉的把持力显著（P < 0.001）高于5.5毫米皮质骨螺钉。5.5毫米皮质骨螺钉在干骺端近端的平均把持力与在干骺端远端的平均把持力无显著差异。与干骺端近端相比，6.5毫米皮质骨、全螺纹松质骨螺钉在干骺端远端的平均把持力显著（P < 0.01）更高。
