BACKGROUND Previous studies assessing surgical fixation of osteoporotic proximal humeral fractures have primarily focused on medial calcar support. In this study, we utilized a specific model for 2-part surgical neck fracture of the osteoporotic proximal humerus to investigate how severe comminution of the greater tuberosity (GT) lateral wall affects biomechanical stability after fixation with a plate. METHODS Ten matched pairs of cadaveric humeri (right and left) were assigned to either a surgical neck fracture alone (the SN group) or a surgical neck fracture with GT lateral wall comminution (the LW group) with use of block randomization. We removed 5 mm of the lateral wall of the GT to simulate severe comminution of the lateral wall. Axial compression stiffness, torsional stiffness, varus bending stiffness, and the single load to failure in varus bending were measured for all plate-bone constructs. RESULTS Compared with the SN group, the LW group showed a significant decrease in all measures, including torsional stiffness (internal, p = 0.007; external, p = 0.007), axial compression stiffness (p = 0.002), and varus bending stiffness (p = 0.007). In addition, the mean single load to failure in varus bending for the LW group was 62% lower than that for the SN group (p = 0.005). CONCLUSIONS Severe comminution of the GT lateral wall significantly compromised the biomechanical stability of osteoporotic, comminuted humeral surgical neck fractures. CLINICAL RELEVANCE Although the generalizability of this cadaveric model may be limited to the extreme clinical scenario, the model showed that severe comminution of the GT lateral wall significantly compromised the stability of osteoporotic humeral surgical neck fractures fixed with a plate and screws alone.

中文翻译：

---

大粗隆的外侧壁完整性对于钢板固定后骨质疏松性近端肱骨骨折的稳定性很重要。


背景 以前评估骨质疏松性肱骨近端骨折手术固定的研究主要集中在内侧颅骨支撑上。在这项研究中，我们利用了骨质疏松性肱骨近端外科颈部骨折的 2 部分手术颈部骨折的特定模型，以研究用钢板固定后大粗隆 （GT） 侧壁的严重粉碎如何影响生物力学稳定性。方法 将 10 对匹配的尸体肱骨 （右和左） 分配给单独的手术颈部骨折 （SN 组） 或手术颈部骨折伴 GT 侧壁粉碎 （LW 组） 使用块随机化。我们去除了 GT 的 5 mm 侧壁，以模拟侧壁的严重粉碎。测量了所有板骨结构的轴向压缩刚度、扭转刚度、内翻弯曲刚度和内翻弯曲中的单一失效载荷。结果 与 SN 组相比，LW 组在所有指标上均显示显着降低，包括扭转刚度 （内部，p = 0.007;外部，p = 0.007）、轴向压缩刚度 （p = 0.002） 和内翻弯曲刚度 （p = 0.007）。此外，LW 组内翻弯曲的平均单载荷失效比 SN 组低 62% （p = 0.005）。结论 GT 侧壁的严重粉碎显着损害了骨质疏松性粉碎性肱骨外科颈部骨折的生物力学稳定性。临床相关性 尽管这种尸体模型的普遍性可能仅限于极端临床情况，但该模型表明，GT 侧壁的严重粉碎显着损害了仅用钢板和螺钉固定的骨质疏松性肱骨外科颈部骨折的稳定性。