新型双叶型肱骨近端锁定钢板的研制与生物力学研究

目的研制新型双叶型肱骨近端锁定钢板以解决复杂肱骨近端骨折大、小结节的固定问题,并通过生物力学实验评估其固定肱骨大、小结节的稳定性。方法取12具新鲜冰冻带肩袖肌的肱骨标本,编号后随机分成A、B两组,建立相同的肱骨大、小结节骨折模型。其中,A组用新型双叶型肱骨近端锁定钢板固定;B组用肱骨近端锁定钢板系统(proximal humeral internal locking system,PHILOS)、缝线缝合固定,小结节同时加用1枚3.5 mm空心螺钉固定。分别对两组标本进行肩胛下肌、冈下肌及小圆肌、冈上肌牵拉实验及大、小结节抗拉实验测试。结果肩胛下肌牵拉实验:A组在180 N拉力以及疲劳实验后位移均明显小于B组(P0.05)。冈下肌及小圆肌牵拉实验:两组在150 N拉力以及疲劳实验后位移比较差异均无统计学意义(P0.05)。冈上肌牵拉实验:两组在90 N拉力以及疲劳实验后位移比较差异均无统计学意义(P0.05)。小结节抗拉实验:A组失效载荷明显大于B组,且A组失效位移明显小于B组(P0.05)。大结节抗拉实验:两组在失效载荷、失效位移比较差异均无统计学意义(P0.05)。结论该新型双叶型肱骨近端锁定钢板对肱骨小结节的固定效果较缝线+空心钉螺钉固定更坚强,具有能同时固定大、小结节的优势。研究结果为临床治疗复杂肱骨近端骨折提供新的选择。

Design and biomechanical study of a novel double-leaf proximal humeral locking plate

Objective To design a novel double-leaf proximal humeral locking plate for fixing greater and lesser tuberosities in complex proximal humeral fractures, and evaluate its fixing stability by biomechanical tests. Methods Twelve fresh-frozen humerus specimens with intact rotator cuff were randomly divided into two groups (Group A and Group B) to establish the same greater and lesser tuberosities fracture models. Specimens in Group A were fixed with the double-leaf proximal humeral locking plate, while specimens in Group B were fixed with the proximal humeral internal locking system (PHILOS) and tension band suture, and a 3.5-mm cannulated screw was added to stabilize the lesser tuberosity. The tensile test on subscapularis, infraspinatus and teres, supraspinatus as well as the load-to-failure test on greater and lesser tuberosities were performed on specimens in two groups. Results For subscapularis tensile tests, displacements under 150 N tensile stretch and after fatigue test in Group A were both significantly smaller than those in Group B (P<0.05). For infraspinatus and teres tensile tests, there were no statistical differences between Group A and B in displacements under 150 N tensile stretch and after fatigue test (P>0.05). For supraspinatus tensile tests, there were no statistical differences between Group A and B in displacements under 90 N tensile stretch and after fatigue test (P>0.05). For load-to-failure tests on lesser tuberosity, the failure load in Group A was significantly greater than that in Group B (P<0.05), and the failure displacement in Group A was significantly smaller than that in Group B (P<0.05). For load-to-failure tests on greater tuberosity, there were no statistical differences between Group A and B in both the failure load and failure displacement (P>0.05). Conclusions Compared with the ordinary tension band suture plus cannulated screw for fixing lesser tuberosity, the novel double-leaf proximal humeral locking plate shows more obvious biomechanical stability, with the advantage of simultaneously fixing greater and lesser tuberosities. The research findings provide a new choice for the clinical treatment of complex proximal humeral fractures.