Department of Orthopedic Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA.
Foot Ankle Int. 2010 Mar;31(3):229-35. doi: 10.3113/FAI.2010.0229.
Internal fixation of the os calcis is often complicated by prolonged soft tissue management and posterior facet disruption. An ideal calcaneal construct would include minimal hardware prominence, sturdy posterior facet fixation and nominal soft tissue disruption. The purpose of this study was to develop such a construct and provide a biomechanical analysis comparing our technique to a standard internal fixation technique.
Twenty fresh-frozen cadaver calcanei were used to create a reproducible Sanders type-IIB calcaneal fracture pattern. One calcaneus of each pair was randomly selected to be fixed using our compressive headless screw technique. The contralateral matched calcaneus was fixed with a nonlocking calcaneal plate in a traditional fashion. Each calcaneus was cyclically loaded at a frequency of 1 Hz for 4000 cycles using an increasing force from 250 N to 1000 N. An Optotrak motion capturing system was used to detect relative motion of the three fracture fragments at eight different points along the fracture lines. Horizontal separation and vertical displacement at the fracture lines was recorded, as well as relative rotation at the primary fracture line.
When the data were averaged, there was more horizontal displacement at the primary fracture line of the plate and screw construct compared to the headless screw construct. The headless screw construct also had less vertical displacement at the primary fracture line at every load. On average those fractures fixed with the headless screw technique had less rotation than those fixed with the side plate technique.
A new headless screw technique for calcaneus fracture fixation was shown to provide stability as good as, or better than, a standard side plating technique under the axial loading conditions of our model. Although further testing is needed, the stability of the proposed technique is similar to that typically provided by intramedullary fixation.
This fixation technique provides a biomechanically stable construct with the potential for a minimally invasive approach and improved post-operative soft tissue healing.
跟骨内固定常因软组织处理时间长和后关节面破坏而变得复杂。理想的跟骨结构应包括最小的硬件突出、坚固的后关节面固定和最小的软组织破坏。本研究旨在开发这样一种结构，并提供一种生物力学分析，将我们的技术与标准内固定技术进行比较。
20 个新鲜冷冻的尸体跟骨用于创建可重复的 Sanders ⅡB 型跟骨骨折模式。每对中的一个跟骨随机选择使用我们的压缩无头螺钉技术进行固定。对侧匹配的跟骨使用传统的非锁定跟骨板固定。每个跟骨在频率为 1Hz 的情况下循环加载 4000 次，施加的力从 250N 逐渐增加到 1000N。使用 Optotrak 运动捕捉系统在骨折线的八个不同点检测三个骨折碎片的相对运动。记录骨折线的水平分离和垂直位移，以及主骨折线的相对旋转。
当数据平均化时，与无头螺钉结构相比，板和螺钉结构在主骨折线处的水平位移更大。无头螺钉结构在主骨折线处的垂直位移也更小。平均而言，用无头螺钉技术固定的骨折比用侧板技术固定的骨折旋转角度更小。
一种新的无头螺钉技术用于跟骨骨折固定，在我们模型的轴向加载条件下，其稳定性与标准侧板技术一样好，甚至更好。尽管需要进一步的测试，但该技术的稳定性与通常由髓内固定提供的稳定性相似。
这种固定技术提供了一种生物力学稳定的结构，具有微创的潜力和改善术后软组织愈合。
