摘要
目的 通过三维有限元分析方法,探讨距螺钉安放在肱骨头下皮质外重建内侧柱的生物力学稳定性。方法 选取1名70岁老年女性志愿者进行肱骨近端CT扫描,在肱骨头内下方5 mm处进行楔形截骨,形成内侧皮质5 mm缺损的三维有限元模型。然后模拟放置肱骨近端锁定钢板(PHILOS),根据距螺钉分布分为3组:A组为距螺钉肱骨头内支撑组,将2枚距螺钉按正常方向打入肱骨头内下象限,从肱骨头内支撑;B组为单螺钉皮质外支撑组,1枚距螺钉打入肱骨头下皮质外,另1枚按正常方向打入肱骨头内;C组为双螺钉皮质外支撑组,2枚距螺钉均打入肱骨头下方皮质外,砥住皮质,从下方托举股骨头。对模型进行轴向力、剪切力和扭转力负荷加载,通过评估肱骨近端和内固定器械的最大等效云应力、肱骨近端位移、颈干角变化和肱骨近端旋转稳定性来比较3组的生物力学稳定性。回顾分析2017年1月—2020年12月收治的7例内侧皮质粉碎的肱骨近端骨折患者,行肱骨近端锁定钢板手术,术中将1枚(5例)或2枚(2例)距螺钉打入肱骨头下皮质外,观察其临床疗效。结果 在轴向力和剪切力作用下,B、C组肱骨近端最大等效云应力大于A组,内固定器械最大等效云应力小于A组,而B、C组应力均相近;3组肱骨近端位移和颈干角变化程度相近,均很小。在扭转力作用下,与A组相比,B、C组肱骨旋转角度略增加,旋转稳定性略下降。7例患者均获随访,随访时间6~12个月。骨折均愈合,愈合时间8~14周,平均10.9周;颈干角变化(末次随访与术后即刻颈干角的差值)为(1.30±0.42)°,肩关节功能Constant评分为(87.4±4.2)分;无肱骨头内翻塌陷、螺钉穿透关节面等并发症发生。结论 对于内侧皮质粉碎的肱骨近端骨折,将锁定钢板的1枚或2枚距螺钉安放在肱骨头下皮质外,同样能有效重建内侧柱稳定性,为临床提供了一种方法。
Objective To explore the biomechanical stability of the medial column reconstructed with the exocortical placement of humeral calcar screw by three-dimensional finite element analysis. Methods A 70-year-old female volunteer was selected for CT scan of the proximal humerus, and a wedge osteotomy was performed 5 mm medially inferior to the humeral head to form a three-dimensional finite element model of a 5 mm defect in the medial cortex.Then, the proximal humeral locking plate(PHILOS) was placed. According to distribution of 2 calcar screws, the study were divided into 3 groups: group A, in which 2 calcar screws were inserted into the lower quadrant of the humeral head in the normal direction for supporting the humeral head;group B, in which 1 calcar screw was inserted outside the cortex below the humeral head, and the other was inserted into the humeral head in the normal direction;group C, in which2 calcar screws were inserted outside the cortex below the humeral head. The models were loaded with axial, shear, and rotational loadings, and the biomechanical stability of the 3 groups was compared by evaluating the peak von mises stress(PVMS) of the proximal humerus and the internal fixator, proximal humeral displacement, neck-shaft angle changes, and the rotational stability of the proximal humerus. Seven cases of proximal humeral fractures with comminuted medial cortex were retrospectively analyzed between January 2017 and December 2020. Locking proximal humeral plate surgery was performed, and one(5 cases) or two(2 cases) calcar screws were inserted into the inferior cortex of the humeral head during the operation, and the effectiveness was observed. Results Under axial and shear force, the PVMS of the proximal humerus in group B and group C was greater than that in group A, the PVMS of the internal fixator in group B and group C was less than that in group A, while the PVMS of the proximal humerus and internal fixator between group B and group C were similar. The displacement of the proximal humerus and the neck-shaft angle change among the3 groups were similar under axial and shear force, respectively. Under the rotational torque, compared with group A, the rotation angle of humerus in group B and group C increased slightly, and the rotation stability decreased slightly. All the7 patients were followed up 6-12 months. All the fractures healed, and the healing time was 8-14 weeks, with an average of10.9 weeks;the neck-shaft angle changes(the difference between the last follow-up and the immediate postoperative neckshaft angle) was(1.30±0.42)°, and the Constant score of shoulder joint function was 87.4±4.2;there was no complication such as humeral head varus collapse and screw penetrating the articular surface. Conclusion For proximal humeral fractures with comminuted medial cortex, exo-cortical placement of 1 or 2 humeral calcar screw of the locking plate outside the inferior cortex of the humeral head can also effectively reconstruct medial column stability, providing an alternative approach for clinical practice.
作者
李波
张世民
胡孙君
杜守超
熊文峰
LI Bo;CHANG Shimin;HU Sunjun;DU Shouchao;XIONG Wenfeng(Department of Orthopaedic Surgery,Yangpu Hospital,Tongji University,Shanghai,200090,P.R.China)
出处
《中国修复重建外科杂志》
CAS
CSCD
北大核心
2022年第8期995-1002,共8页
Chinese Journal of Reparative and Reconstructive Surgery
关键词
肱骨近端骨折
内侧柱重建
距螺钉
皮质外支撑
三维有限元分析
Proximal humerus fracture
medial column reconstruction
calcar screw
exo-cortical buttress
threedimensional finite element analysis
