Claes L, Hutzschenreuter P
Z Orthop Ihre Grenzgeb. 1977 Apr;115(2):235-8.
In vitro examinations on deformation and relaxation were carried out on cortical countersink of different geometry under a compression load of up to 2000 N through a screw head. Conical countersink showed plastic deformations of an average of 1300 N whereas with spherical countersink they did not occur at the same load. After reaching the load of 2000 N and keeping the deformation constant we saw a significantly stronger reduction of force with the conical countersink then with the spherical type. As far as fracture fixation is concerned a smaller postoperative reduction of screw force can be expected if applying a cortical screw with a spherical head in a spherical countersink.
通过螺钉头在高达2000 N的压缩载荷下，对不同几何形状的皮质埋头孔进行了体外变形和松弛测试。锥形埋头孔平均在1300 N时出现塑性变形，而球形埋头孔在相同载荷下未出现塑性变形。在达到2000 N的载荷并保持变形恒定时，我们发现锥形埋头孔的力下降明显比球形埋头孔更强。就骨折固定而言，如果在球形埋头孔中应用球形头部的皮质螺钉，预计术后螺钉力的下降会更小。
