目的 基于关节镜肩袖修复（rotator cuff repair, RCR）手术中使用带线锚钉（suture anchor，SA）植入肱骨的角度问题，对带线锚钉的最终拔出强度进行生物力学评估。方法 采用密度分别为0.16、0.32 g/cm3聚氨酯材料模拟骨质疏松性和正常松质骨，厚度3 mm、密度0.64 g/cm3聚氨酯材料模拟人体皮质骨，两种松质骨模型分别与皮质骨模型粘连在一起构造人体肱骨模型。使用钛金属带线锚钉以45°、60°、75°和90°角度植入肱骨模型，对其进行连续的拉拔实验，其中肱骨模型表面和缝线间使用45°锚钉牵引方向模拟岗上肌的生理牵引方向，每组不间断地进行8次测试，记录最终的拔出力和破坏模式。结果 高密度骨质模型的拔出力明显高于低密度骨质模型（P＜0.001），且在同密度下，相比45°、60°和75°，90°植入角拥有更大的拔出力（P＜0.01）。结论 在肱骨模型中带线锚钉采用90°植入显示出更优的生物力学性能，而且在肩袖修复中锚钉的垂直植入对术中打结和术后冈上肌的恢复均有益处。
Objective To make biomechanical evaluation on ultimate pullout strength of the suture anchors based on the angle of suture anchor (SA) implanted into the humerus during arthroscopic rotator cuff repair (RCR) surgery. Methods Polyurethane materials with densities of 0.16 g/cm3 and 0.32 g/cm3 were used to simulate osteoporosis and normal cancellous bone, and polyurethane materials with densities of 0.64 g/cm3 and 3 mm thickness were used to simulate human cortical bone. The two kinds of cancellous bone models were respectively adhered together with cortical bone model to construct human humerus model. Titanium metal suture anchors were inserted into humerus models at 45°, 60°, 75° and 90° angle, then the continuous tensile experiments were performed, and 45° pulling direction between the humerus model surface and suture anchor was used to simulate the supraspinatus physiological traction direction, and each group was continuously tested 8 times, recording the pullout strength and failure modes. ResultsThe pullout force of high-density bone models was significantly higher than that of low-density bone models (P＜0.001), and at the same density, compared with 45°, 60° and 75°, the implant angle of 90° has a larger pullout force (P＜0.01). Conclusions In the model of humerus, the 90° implantation of suture anchor showed better biomechanical properties, and the vertical implantation of anchor in the repair of rotator cuff was beneficial to the knotting during operation and postoperative recovery of the supraspinatus.