Department of Orthopedics and Trauma Surgery, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany; GERN Gewebeersatz, Regeneration & Neogenese (Tissue Replacement, Regeneration & Neogenesis), Faculty of Medicine, Department of Orthopedics and Trauma Surgery, Medical Center, Albert Ludwig University of Freiburg, Freiburg, Germany.
Department of Orthopedics and Trauma Surgery, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
J Shoulder Elbow Surg. 2021 Jul;30(7):1519-1526. doi: 10.1016/j.jse.2020.11.008. Epub 2020 Dec 24.
In the treatment of unstable olecranon fractures, anatomically preshaped locking plates exhibit superior biomechanical results compared with tension band wiring. However, posterior plating (PP) still is accompanied by high rates of plate removal because of soft-tissue irritation and discomfort. Meanwhile, low-profile plates precontoured for collateral double plating (DP) are available and enable muscular soft-tissue coverage combined with angular-stable fixation. The goal of this study was to biomechanically compare PP with collateral DP for osteosynthesis of unstable osteoporotic fractures.
A comminuted displaced Mayo type IIB fracture was created in 8 osteoporotic pairs of fresh-frozen human cadaveric elbows. Pair-wise angular stable fixation was performed by either collateral DP or PP. Biomechanical testing was conducted as a pulling force to the triceps tendon in 90° of elbow flexion. Cyclical load changes between 10 and 300 N were applied at 4 Hz for 50,000 cycles. Afterward, the maximum load was raised by 0.02 N/cycle until construct failure, which was defined as displacement > 2 mm. Besides failure cycles and failure loads, modes of failure were analyzed.
Following DP, a median endurance of 65,370 cycles (range, 2-83,121 cycles) was recorded, which showed no significant difference compared with PP, with 69,311 cycles (range, 150-81,938 cycles) (P = .263). Failure load showed comparable results as well, with 601 N (range, 300-949 N) after DP and 663 N (range, 300-933 N) after PP (P = .237). All PP constructs and 3 of 8 DP constructs failed by proximal fragment cutout, whereas 5 of 8 DP constructs failed by bony triceps avulsion.
Angular-stable DP showed comparable biomechanical stability to PP in unstable osteoporotic olecranon fractures under high-cycle loading conditions. Failure due to bony triceps avulsion following DP requires further clinical and biomechanical investigation, for example, on suture augmentation or different screw configurations.
在不稳定型尺骨鹰嘴骨折的治疗中，解剖预成型锁定钢板的生物力学结果优于张力带钢丝固定。然而，由于软组织刺激和不适，后钢板（PP）的移除率仍然很高。同时，可用于外侧双钢板（DP）预塑形的低轮廓钢板可实现肌肉软组织覆盖并结合角稳定固定。本研究的目的是生物力学比较不稳定型骨质疏松性骨折的 PP 与外侧 DP 内固定。
在 8 对新鲜冷冻人尸肘的粉碎性移位 Mayo Ⅱ B 型骨折中创建了粉碎性移位 Mayo Ⅱ B 型骨折。通过外侧 DP 或 PP 进行粉碎性移位 Mayo Ⅱ B 型骨折的角稳定固定。在 90°肘弯曲下，对三头肌肌腱进行拉力测试。在 4 Hz 下施加 10 至 300 N 的循环负荷变化，进行 50,000 次循环。之后，以 0.02 N/循环的速度逐渐增加最大负荷，直到结构失效，定义为位移>2mm。除了失效循环和失效载荷外，还分析了失效模式。
DP 后记录的中位耐力为 65,370 次循环（范围，2-83,121 次循环），与 PP 相比无显著差异，PP 为 69,311 次循环（范围，150-81,938 次循环）（P =.263）。失效载荷也有类似的结果，DP 后为 601 N（范围，300-949 N），PP 后为 663 N（范围，300-933 N）（P =.237）。所有 PP 结构和 8 个 DP 结构中的 3 个因近端片段脱出而失效，而 8 个 DP 结构中的 5 个因肱三头肌撕脱性骨折而失效。
在高循环负荷条件下，不稳定型骨质疏松性尺骨鹰嘴骨折中，角稳定 DP 的生物力学稳定性与 PP 相当。DP 后因肱三头肌撕脱引起的失效需要进一步的临床和生物力学研究，例如缝线增强或不同的螺钉配置。
