Department of Orthopedic Surgery, Gwangju Veterans Hospital, 99 Cheomdanwolbong-ro, Gwangsan-gu, Gwangju, 62284, South Korea.
Osong Medical Innovation Foundation, Medical Device Development Center, Cheongju, South Korea.
BMC Musculoskelet Disord. 2021 Sep 8;22(1):767. doi: 10.1186/s12891-021-04658-y.
When a hip screw needs to be changed, choosing between the conventional (C-type) and helical blade (H-type) types is difficult. In this biomechanical study, we compared these two screw types relative to the type of the initial screw used.
C- or H-type screws were inserted (leading screw) in three types of polyurethane bone models (Sawbone, Pacific Research Laboratories, Inc., Washington, USA: 130 × 180 × 40 mm) of different bone mineral densities (pounds per cubic feet [PCF] 5, 80 kg/m; PCF 10, 160 kg/m; and PCF 15, 240 kg/m), and then successively or alternately inserted (following screw) after the leading screw removal. An original model (original C and H) of a leading screw without removal was created as a control. The strengths of resistance to pullout (PO) and rotational stress were measured. For each experimental condition, there were 30 experimental models.
The original C screw was superior in PO strength, and the original H-type screw was superior in rotational strength. When the C- or H-type screw was the leading screw, using the C-type screw again as the following screw (C1-C2, H1-C2) showed the greatest resistance to PO, and using the H-type screw as the following screw (C1-H2, H1-H2) showed superior resistance to rotational strength. However, the rotational strength of the C2 screw decreased by more than 50% compared with that of the original C screw. Moreover, the PO and rotational strengths of the H2 screw decreased to less than 30% overall compared with those of the original H screw.
The H-type screw should be used for second-time screw insertion procedures in cases where it is difficult to choose between PO and rotational strengths.
当需要更换髋螺钉时，在传统（C 型）和螺旋刀片（H 型）之间进行选择较为困难。在这项生物力学研究中，我们比较了这两种螺钉类型与初始螺钉类型的关系。
在三种不同骨密度（磅每立方英尺[PCF]5，80kg/m；PCF10，160kg/m；和 PCF15，240kg/m）的聚氨酯骨模型（Sawbone，Pacific Research Laboratories，Inc.，华盛顿州：130×180×40mm）中分别插入 C 型或 H 型螺钉（主导螺钉），然后在取出主导螺钉后，依次或交替插入（后续螺钉）。创建一个没有取出的主导螺钉的原始模型（原始 C 和 H）作为对照。测量抗拔出强度（PO）和旋转强度。对于每种实验条件，有 30 个实验模型。
原始 C 螺钉在 PO 强度方面表现优异，而原始 H 型螺钉在旋转强度方面表现优异。当 C 型或 H 型螺钉为主导螺钉时，再次使用 C 型螺钉作为后续螺钉（C1-C2，H1-C2）时，其抗 PO 能力最强，而使用 H 型螺钉作为后续螺钉（C1-H2，H1-H2）时，其抗旋转强度最强。然而，C2 螺钉的旋转强度比原始 C 螺钉降低了 50%以上。此外，H2 螺钉的 PO 和旋转强度总体上降低到原始 H 螺钉的 30%以下。
在难以选择 PO 和旋转强度时，应选择 H 型螺钉进行二次螺钉插入操作。
