Yerby S, Scott C C, Evans N J, Messing K L, Carter D R
Rehabilitation Research and Development Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, California, U.S.A.
J Orthop Trauma. 2001 Mar-Apr;15(3):216-21. doi: 10.1097/00005131-200103000-00012.
To determine the effect of the number and length of cutting flutes on the insertion torque and pullout strength for self-tapping 4.5-millimeter cortical bone screws.
Screws were self-tapped in the diaphysis of human cadaver femurs. Each of the six screw types studied had different designs with varying cutting flute lengths and numbers. Bone mineral density, insertion torque, and pullout strength were measured.
The study was conducted at an experimental biomechanics laboratory associated with a university medical center.
Insertion torque and pullout strength were normalized by the local bone mineral density.
The mean normalized insertion torque of the design with four full-length cutting flutes was less than the design with three full-length flutes and the two designs with one-third length flutes (p < 0.05). The mean normalized pullout strength of the screw with four full-length flutes was significantly greater than that of all screws with fewer than three flutes (p < 0.05).
Priorities for a cutting flute design should ideally include ease of screw insertion, minimal soft tissue irritation, and maximal screw holding power. Screws with more than two flutes were easier to insert and did not cause cortical damage during insertion. The screw with four full-length flutes showed a trend toward being the easiest to insert and having the greatest holding strength.
确定自攻型4.5毫米皮质骨螺钉的切削槽数量和长度对植入扭矩和拔出强度的影响。
将螺钉自攻植入人类尸体股骨骨干。所研究的六种螺钉类型中的每一种都有不同的设计，切削槽长度和数量各不相同。测量骨矿物质密度、植入扭矩和拔出强度。
该研究在与一所大学医学中心相关的实验生物力学实验室进行。
植入扭矩和拔出强度通过局部骨矿物质密度进行标准化。
具有四个全长切削槽的设计的平均标准化植入扭矩低于具有三个全长切削槽的设计以及具有三分之一长度切削槽的两种设计（p < 0.05）。具有四个全长切削槽的螺钉的平均标准化拔出强度显著高于所有少于三个切削槽的螺钉（p < 0.05）。
切削槽设计的理想优先考虑因素应包括易于螺钉植入、对软组织刺激最小以及最大的螺钉固定力。具有两个以上切削槽的螺钉更容易植入，并且在植入过程中不会造成皮质骨损伤。具有四个全长切削槽的螺钉显示出最易于植入且具有最大固定强度的趋势。
