Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
Department of Orthopedics, Fudan University Affiliated Huadong Hospital, Shanghai, China.
J Shoulder Elbow Surg. 2022 Apr;31(4):782-791. doi: 10.1016/j.jse.2021.08.033. Epub 2021 Oct 5.
Achieving medial support for proximal humeral fractures (PHFs) by regular calcar screw positioning is challenging when the humeral head is small or locking plates are placed distally, as there are unable inserted calcar screws into the humeral head. We aimed to investigate the suitability of the 2 strategies, slotting calcar screw (SCS) and off-axis calcar screw (OCS), to achieve medial support for PHFs.
Regular calcar screw (RCS), SCS, OCS, and noncalcar screw (NCS) were tested via mechanical experiments and finite element analysis (FEA), using synthetic bones for biomechanical comparisons. All PHFs treated in our hospital from March 2017 to March 2019 were reviewed. The patients were divided into 3 groups based on the calcar screw fixation: RCS, SCS, and OCS. The postoperative varus collapse (neck-shaft angle changed to less than 120°) and Disabilities of the Arm, Shoulder and Hand (DASH) scores were recorded.
The properties of RCS, SCS, and OCS against the torsion and varus force were superior to those of NCS, whereas the stiffness of SCS, OCS, and RCS were similar. FEA predicted lower peri-screw strains in the OCS and SCS than in the RCS, indicating a lower risk of cut-out. Patients (n = 125; 75 female, 50 male) aged 55.9 ± 13.0 years were evaluated. Compared with the RCS (5/55), varus collapse incidences were not significantly higher following SCS (0/29, P = .094) or OCS (3/41, P = .756), and neither were DASH scores (P = .867 and .736, respectively).
This study is a preliminary study demonstrating that the SCS and OCS fixation strategies could be useful alternatives when regular calcar fixation is not possible using the plate at hand.
当肱骨头部较小或锁定板放置在远端时，通过常规的距骨螺钉定位实现肱骨近端骨折（PHF）的内侧支撑具有挑战性，因为无法将距骨螺钉插入肱骨头部。我们旨在研究 2 种策略（开槽距骨螺钉[SCS]和偏距距骨螺钉[OCS]）在实现 PHF 内侧支撑方面的适用性。
通过机械实验和有限元分析（FEA）使用合成骨进行生物力学比较，对常规距骨螺钉（RCS）、SCS、OCS 和非距骨螺钉（NCS）进行了测试。回顾了 2017 年 3 月至 2019 年 3 月在我院治疗的所有 PHF 患者。根据距骨螺钉固定情况将患者分为 3 组：RCS、SCS 和 OCS。记录术后内翻塌陷（颈干角小于 120°）和手臂、肩部和手部残疾（DASH）评分。
RCS、SCS 和 OCS 的扭转和内翻力性能优于 NCS，而 SCS、OCS 和 RCS 的刚度相似。FEA 预测 OCS 和 SCS 的螺钉周围应变低于 RCS，表明发生切出的风险较低。共评估了 125 例患者（75 例女性，50 例男性；年龄 55.9±13.0 岁）。与 RCS（5/55）相比，SCS（0/29，P=0.094）或 OCS（3/41，P=0.756）组的内翻塌陷发生率无显著升高，DASH 评分也无显著升高（分别为 P=0.867 和 0.736）。
本研究初步表明，当手头的钢板无法进行常规距骨固定时，SCS 和 OCS 固定策略可能是有用的替代方法。
