Department of Orthopaedic Surgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
J Orthop Trauma. 2012 Oct;26(10):e188-92. doi: 10.1097/BOT.0b013e31823db922.
Screw perforation of the humeral head in locking plate osteosynthesis occurs in up to 30% of cases. The current study compared different fixation possibilities (eg, number and position of screws) to reduce screw perforation in the humeral head.
A humeral head fracture with a missing medial support was created in 30 fresh-frozen cadavers and fixed with a polyaxial locking plate (NCB PH; Zimmer, Warsaw, IN). The constructs were loaded with increasing force and the number of cycles until screw perforation was recorded. Four different fixation methods were tested: group 1 five screws with fixed angle, group 2 five screws in polyaxial position according to bone strength, group 3 three screws, and group 4 five screws with 1 as an inferomedial support screw.
More screws in the humeral head significantly increased the number of cycles before screw perforation. An inferomedial support screw further increased the number of cycles. Polyaxial screw placement compared with fixed-angle placement had no effect on the screw perforation phenomenon.
We recommend to position an inferomedial support screw, and at least 5 screws in the head fragment, when using a locking plate in proximal humerus fractures with disrupted medial hinge.
锁定钢板接骨术中，肱骨头上的螺钉穿孔发生率高达 30%。本研究比较了不同的固定方式（例如螺钉的数量和位置），以减少肱骨头上的螺钉穿孔。
在 30 个新鲜冷冻的尸体标本上创建了一个缺少内侧支撑的肱骨头部骨折，并使用多轴锁定钢板（NCB PH； Zimmer，华沙，印第安纳州）进行固定。在记录螺钉穿孔之前，对这些结构进行逐渐增加的力和循环次数的加载。测试了四种不同的固定方法：组 1 为 5 个具有固定角度的螺钉，组 2 为 5 个根据骨强度呈多轴位置的螺钉，组 3 为 3 个螺钉，组 4 为 5 个螺钉，其中 1 个为下内侧支撑螺钉。
更多的螺钉在肱骨头上显著增加了螺钉穿孔之前的循环次数。下内侧支撑螺钉进一步增加了循环次数。与固定角度放置相比，多轴螺钉放置对螺钉穿孔现象没有影响。
当使用锁定钢板治疗内侧铰链中断的肱骨近端骨折时，我们建议在头部骨折块中放置一个下内侧支撑螺钉，并且至少放置 5 个螺钉。
