Archdeacon Michael T, Arebi Sameh, Le T Toan, Wirth Rene, Kebel Roland, Thakore Mayur
Department of Orthopaedic Surgery, College of Medicine, University of Cincinnati, Cincinnati, OH 45267-0212, USA.
J Orthop Trauma. 2009 Feb;23(2):100-5. doi: 10.1097/BOT.0b013e3181962e0e.
The purpose of this study is to compare the structural stiffness of an orthogonal pelvic external fixator pin construct with 2 different parallel external fixator pin constructs in a simulated bone model.
An orthogonal pelvic external fixator pin construct would be significantly more stiff than a parallel pin construct when loaded in-plane under similar conditions.
Thirty synthetic pelvic bone models were configured with orthogonal pins (group 1), parallel iliac crest pins (group 2), or parallel supra-acetabular pins (group 3). Specimens were loaded either in-plane (flexion/extension moment) or out-of-plane (internal/external rotation moment) to assess construct stiffness.
Orthopaedic industry mechanical testing laboratory (Stryker Orthopedics, Mahwah, NJ).
Single load cycle to failure with load application modified to assess stiffness both in-plane and out-of-plane with the pin constructs.
Pelvic external fixation pin construct stiffness.
Stiffness for in-plane loading was 150.2 +/- 51.2 N/mm for the orthogonal pin construct, 105.0 +/- 46.9 N/mm for the iliac crest pin construct, and 104.7 +/- 20.7 N/mm for the supra-acetabular pin construct. Pairwise comparisons demonstrated that the difference was significant (P < 0.05) between groups 1 and 2 and groups 1 and 3 but not between groups 2 and 3. Stiffness for out-of-plane loading was 49.6 +/- 3.4 N/mm for the orthogonal pin construct, 53.9 +/- 3.5 N/mm for the iliac crest pin construct, and 100.6 +/- 4.3 N/mm for the supra-acetabular pin construct, with significant differences (P < 0.05) between groups 1 and 3 and groups 2 and 3 but not between groups 1 and 2.
An orthogonal pelvic external fixator pin construct produced a significantly stiffer construct for in-plane loading (flexion/extension moment) compared with either parallel pin construct; however, a parallel supra-acetabular pin construct was stiffer for out-of-plane loading.
本研究旨在比较在模拟骨模型中，正交骨盆外固定针结构与两种不同平行外固定针结构的结构刚度。
在相似条件下进行平面内加载时，正交骨盆外固定针结构比平行针结构的刚度显著更高。
30个合成骨盆骨模型分别配置正交针（第1组）、平行髂嵴针（第2组）或平行髋臼上针（第3组）。对标本进行平面内（屈伸力矩）或平面外（内/外旋转力矩）加载，以评估结构刚度。
骨科行业机械测试实验室（史赛克骨科，新泽西州马哈瓦）。
进行单次加载直至失效，调整加载方式以评估针结构在平面内和平面外的刚度。
骨盆外固定针结构刚度。
平面内加载时，正交针结构的刚度为150.2±51.2N/mm，髂嵴针结构为105.0±46.9N/mm，髋臼上针结构为104.7±20.7N/mm。两两比较显示，第1组与第2组、第1组与第3组之间差异有统计学意义（P＜0.05），但第2组与第3组之间无差异。平面外加载时，正交针结构的刚度为49.6±3.4N/mm，髂嵴针结构为53.9±3.5N/mm，髋臼上针结构为100.6±4.3N/mm，第1组与第3组、第2组与第3组之间差异有统计学意义（P＜0.05），但第1组与第2组之间无差异。
与任何一种平行针结构相比，正交骨盆外固定针结构在平面内加载（屈伸力矩）时产生的结构刚度显著更高；然而，平行髋臼上针结构在平面外加载时刚度更高。
