Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, 600 Yishan Road, Shanghai, 200233, China.
BMC Musculoskelet Disord. 2024 Jul 11;25(1):533. doi: 10.1186/s12891-024-07660-2.
The purpose of this study was to perform a biomechanical analysis to compare different medial column fixation patterns for valgus pilon fractures in a case-based model.
Based on the fracture mapping, 48 valgus pilon fracture models were produced and assigned into four groups with different medial column fixation patterns: no fixation (NF), K-wires (KW), intramedullary screws (IS), and locking compression plate (LCP). Each group contained wedge-in and wedge-out subgroups. After fixing each specimen on the machine, gradually increased axial compressive loads were applied with a load speed of one millimeter per minute. The maximum peak force was set at 1500 N. Load-displacement curves were generated and the axial stiffness was calculated. Five different loads of 200 N, 400 N, 600 N, 800 N, 1000 N were selected for analysis. The specimen failure was defined as resultant loading displacement over 3 mm.
For the wedge-out models, Group-IS showed less displacement (p < 0.001), higher axial stiffness (p < 0.01), and higher load to failure (p < 0.001) than Group-NF. Group-KW showed comparable displacement under loads of 200 N, 400 N and 600 N with both Group-IS and Group-LCP. For the wedge-in models, no statistical differences in displacement, axial stiffness, or load to failure were observed among the four groups. Overall, wedge-out models exhibited less axial stiffness than wedge-in models (all p < 0.01).
Functional reduction with stable fixation of the medial column is essential for the biomechanical stability of valgus pilon fractures and medial column fixation provides the enough biomechanical stability for this kind of fracture in the combination of anterolateral fixation. In detail, the K-wires can provide a provisional stability at an early stage. Intramedullary screws are strong enough to provide the medial column stability as a definitive fixation. In future, this technique can be recommended for medial column fixation as a complement for holistic stability in high-energy valgus pilon fractures.
本研究旨在通过基于病例的模型对不同内侧柱固定方式的内翻型 Pilon 骨折进行生物力学分析。
根据骨折映射图，制作 48 个内翻型 Pilon 骨折模型，并根据不同的内侧柱固定方式分为四组：无固定（NF）、克氏针（KW）、髓内钉（IS）和锁定加压钢板（LCP）。每组均分为楔形内固定和楔形外固定亚组。将每个标本固定在机器上后，以每分钟 1 毫米的速度逐渐增加轴向压缩载荷。将最大峰值力设定为 1500 N。生成载荷-位移曲线，并计算轴向刚度。选择 200 N、400 N、600 N、800 N、1000 N 等五个不同的载荷进行分析。定义标本失效为总加载位移超过 3 毫米。
对于楔形外固定模型，与 NF 组相比，IS 组的位移较小（p<0.001），轴向刚度较高（p<0.01），断裂载荷较高（p<0.001）。KW 组在 200 N、400 N 和 600 N 载荷下的位移与 IS 组和 LCP 组相似。对于楔形内固定模型，四组间的位移、轴向刚度和断裂载荷无统计学差异。总体而言，楔形外固定模型的轴向刚度小于楔形内固定模型（均 p<0.01）。
内侧柱的功能复位和稳定固定对内翻型 Pilon 骨折的生物力学稳定性至关重要，内侧柱固定结合前外侧固定为这种骨折提供了足够的生物力学稳定性。具体来说，克氏针可以在早期提供临时稳定性。髓内钉足够强大，可以作为最终固定提供内侧柱稳定性。在未来，这种技术可以作为内侧柱固定的推荐方法，作为高能内翻型 Pilon 骨折整体稳定性的补充。
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