Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, Germany.
Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Münster, Germany.
J Shoulder Elbow Surg. 2021 Dec;30(12):2852-2861. doi: 10.1016/j.jse.2021.04.041. Epub 2021 May 19.
Fractures of the proximal humerus are common. The most frequent surgical treatment option is open reduction and locking plate fixation. Multifragmentary fractures, including 3- and 4-part fractures, are especially challenging to treat because they correlate with an increased risk of fixation failure. In the past, several mechanisms of additional fixation were investigated, but none directly addressed the lesser tuberosity (LT). The goal of this study was to investigate the biomechanical impact of additional anterior fracture fixation in lateral locked plating (LLP) of 4-part proximal humeral fractures (PHFs).
Twenty-seven fresh frozen human shoulder specimens (mean age, 80 years) with intact rotator cuffs (RCs) were randomized into 4 groups: 3-part PHF with LLP and RC cerclage (n = 6); 4-part PHF with LLP and RC cerclage as standard of care (n = 7); 4-part PHF with LLP, RC cerclage, and 2 anterior 3.5-mm cortical screws (n = 7); and 4-part PHF with LLP, RC cerclage, and additional anterior one-third tubular plate (additional anterior plating [AAP], n = 7). Static load of the RC was simulated with weights. A force-controlled cyclic loading test was performed with a servo-hydraulic testing machine, followed by load-to-failure testing. An optical motion capture system recorded humeral head range of motion.
LLP of a 4-part PHF showed more humeral head motion than LLP of a 3-part PHF without fracture of the LT (P < .001). Fixing the LT to the humeral head with two 3.5-mm screws significantly reduced humeral head motion compared with LLP with RC cerclage alone (P < .006). Using AAP significantly increased the construct stiffness compared with the standard of care (P = .03).
LLP of a 4-part PHF is biomechanically less stable than LLP of a 3-part PHF without fracture of the LT. Additional screw fixation of the LT in 4-part PHFs improves stability compared with LLP alone. In case of metaphyseal comminution, AAP is favorable from a biomechanical perspective.
肱骨近端骨折很常见。最常见的手术治疗选择是切开复位和锁定钢板固定。多段骨折，包括 3 部分和 4 部分骨折，治疗尤其具有挑战性，因为它们与固定失败的风险增加相关。过去，研究了几种附加固定的机制，但没有一种直接针对小结节（LT）。本研究的目的是研究外侧锁定钢板（LLP）治疗 4 部分肱骨近端骨折（PHF）时，附加前侧骨折固定对生物力学的影响。
27 个新鲜冷冻的完整肩袖（平均年龄 80 岁）随机分为 4 组：LLP 和 RC 环扎治疗 3 部分 PHF（n = 6）；LLP 和 RC 环扎作为标准治疗的 4 部分 PHF（n = 7）；LLP、RC 环扎和 2 个前侧 3.5mm 皮质螺钉（n = 7）；以及 LLP、RC 环扎和附加前侧三分之一管状钢板（附加前侧钢板[AAP]，n = 7）治疗 4 部分 PHF。用重物模拟 RC 的静态负荷。使用伺服液压试验机进行力控制循环加载试验，然后进行失效负载测试。光学运动捕捉系统记录肱骨头活动范围。
与未发生 LT 骨折的 3 部分 PHF 的 LLP 相比，4 部分 PHF 的 LLP 显示出更大的肱骨头运动（P <.001）。与单独使用 RC 环扎相比，将 LT 固定到肱骨头的两个 3.5mm 螺钉显著减少了肱骨头运动（P <.006）。与标准治疗相比，使用 AAP 显著增加了构建的刚度（P =.03）。
与未发生 LT 骨折的 3 部分 PHF 的 LLP 相比，4 部分 PHF 的 LLP 在生物力学上不太稳定。在 4 部分 PHF 中，LT 的附加螺钉固定与单独使用 LLP 相比可提高稳定性。在干骺端粉碎的情况下，从生物力学的角度来看，AAP 是有利的。
