Grubhofer Florian, Bachmann Elias, Gerber Christian, Wieser Karl, Ernstbrunner Lukas, Warner Jon Jp, Bouaicha Samy
Balgrist University Hospital, Department of Orthopedics, University of Zürich, Zürich, Switzerland.
Massachusetts General Hospital, Department of Orthopedics, Harvard Medical School, Boston, MA, USA.
JSES Int. 2020 Dec 14;5(2):270-276. doi: 10.1016/j.jseint.2020.10.016. eCollection 2021 Mar.
The treatment of complex proximal humerus fractures in the elderly with reverse total shoulder arthroplasty is an established treatment option. Healing of the greater tuberosity (GT) is associated with better outcomes. It was the aim of this cadaver study to compare the stability of GT refixation obtained with the so-called "cow hitch" cerclage fixation with that of the recommended standard suture cerclage technique.
A 4-part proximal humerus fracture was created in 10 fresh-frozen, human cadaveric shoulders. A CT was performed preoperatively to ensure the comparability of bone density and fracture patterns. In the experimental group the GT was reattached to the stem of the reverse total shoulder arthroplasty with the "cow hitch" suture cerclage (CH) technique, the conventional (CON) technique recommended for the tested implant was used in the control group. Humeri were tested with a uniaxial material testing machine. In total, 5000 loading cycles with forces from 250 to 350N were applied while motion (in mm) of the tuberosities was recorded with a telecentric camera.
After 5000 loading cycles, the CH group showed a significantly smaller displacement of the bone fragment (0.74 ± 0.31 mm) than the CON group [2.29 ± 1.08 mm ( < .05)]. After the first three cycles the mean displacement was 0.14 mm (±0.12) in the CH and 1.42 mm (±0.21) in the CON ( < .0001) groups.
GT reattachment with the "cow hitch" suture cerclage showed a significantly more stable fixation compared with the currently for the used prosthetic system recommended suture cerclage technique in an in vitro 4-part proximal humeral fracture model.
采用反式全肩关节置换术治疗老年复杂肱骨近端骨折是一种既定的治疗选择。大结节（GT）愈合与更好的治疗效果相关。本尸体研究的目的是比较采用所谓“牛结”环扎固定法进行GT重新固定与推荐的标准缝线环扎技术所获得的稳定性。
在10个新鲜冷冻的人体尸体肩部制造四部分肱骨近端骨折。术前进行CT扫描以确保骨密度和骨折类型具有可比性。在实验组中，采用“牛结”缝线环扎（CH）技术将GT重新附着于反式全肩关节置换术的柄上，对照组使用针对测试植入物推荐的传统（CON）技术。使用单轴材料试验机对肱骨进行测试。总共施加5000次加载循环，力从250N到350N，同时用远心相机记录结节的位移（以毫米为单位）。
在5000次加载循环后，CH组的骨块位移（0.74±0.31mm）明显小于CON组[2.29±1.08mm（P<0.05）]。在前三个循环后，CH组的平均位移为0.14mm（±0.12），CON组为1.42mm（±0.21）（P<0.0001）。
在体外四部分肱骨近端骨折模型中，与目前针对所用假体系统推荐的缝线环扎技术相比，采用“牛结”缝线环扎进行GT重新固定显示出明显更稳定的固定效果。
