Choueka J, Koval K J, Kummer F J, Zukerman J D
Department of Orthopaedic Surgery, Hospital for Joint Diseases, New York, NY 10003, USA.
Acta Orthop Scand. 1996 Apr;67(2):153-7. doi: 10.3109/17453679608994661.
We evaluated 2 techniques of cement augmentation to enhance fixation of intertrochanteric hip fractures. 4 fixation groups with 6 cadaver femurs in each group were compared: stainless steel lag screw and side plate with and without cement augmentation and a titanium alloy expandable dome plunger and side plate with and without cement augmentation. Gauges were used to establish the mechanical behavior of intact and then fractured femurs to simple uniaxial loads. Subsequent loading to failure allowed determination of maximum fixation strengths and modes of failure. Cement augmentation of each device increased its load to failure. There was no significant difference between the cemented lag screw and the uncemented dome plunger groups with average loads to failure of 4.0 x 10(3) N. The greatest average load to failure was in the cemented dome plunger group (5.6 x 10(3) N) with the lowest in the uncemented sliding hip screw group (3.6 x 10(3) N). Device cut-out as a cause of failure occurred mostly in the uncemented lag screw group. Sliding was enhanced by those methods that increased the fixation surface area within the femoral head, unless cement encroached in the region of the barrel-screw junction. Strain analysis showed that the dome plunger unloaded the bone at the calcar, regardless of cement augmentation, while the sliding hip screw allowed for compressive stresses in this area. Proper cement augmentation increases load to failure and minimizes nail cut-out for both devices studied. However, the dome plunger, a device with a large fixation area in the femoral head, was equally effective and eliminated potential cement encroachment. Failure of intertrochanteric fracture fixation in osteoporotic bone may be minimized by an appropriate choice of device or cement augmentation.
我们评估了两种骨水泥强化技术，以增强股骨转子间骨折的固定效果。比较了4个固定组，每组6具尸体股骨：有和没有骨水泥强化的不锈钢拉力螺钉和侧板，以及有和没有骨水泥强化的钛合金可扩张球头柱塞和侧板。使用应变仪确定完整股骨以及骨折股骨在简单单轴载荷下的力学行为。随后加载至破坏，以确定最大固定强度和破坏模式。每种装置进行骨水泥强化后，其破坏载荷均增加。骨水泥强化拉力螺钉组和未使用骨水泥的球头柱塞组之间无显著差异，平均破坏载荷为4.0×10³N。平均破坏载荷最大的是骨水泥强化球头柱塞组（5.6×10³N），最小的是未使用骨水泥的滑动髋螺钉组（3.6×10³N）。作为失效原因的装置穿出大多发生在未使用骨水泥的拉力螺钉组。增加股骨头内固定表面积的方法可增强滑动，除非骨水泥侵入套筒 - 螺钉连接处区域。应变分析表明，无论是否进行骨水泥强化，球头柱塞均使股骨距处的骨卸载，而滑动髋螺钉则使该区域产生压应力。对于所研究的两种装置，适当的骨水泥强化可增加破坏载荷并使钉穿出最小化。然而，球头柱塞这种在股骨头内具有大固定面积的装置同样有效，且消除了骨水泥侵入的可能性。通过适当选择装置或进行骨水泥强化，可使骨质疏松性骨中股骨转子间骨折固定的失败率降至最低。
