空心拉力钉锁定板与空心钉固定股骨颈骨折的生物力学研究

Biomechanical research of hollow screws and static locking plate with hollow lag screws for femoral neck fracture

目的通过对空心拉力钉锁定板与空心钉固定股骨颈骨折模型生物力学测试,探讨两种内固定器固定股骨颈骨折的生物力学差异。方法选择16具新鲜冰冻股骨标本,其中男性8具,女性8具;年龄45^60岁,平均年龄51岁。经股骨颈截骨制作经颈型股骨颈骨折模型。随机分为2组,即空心拉力钉锁定板组和空心钉组。解剖复位后分别以空心拉力钉锁定板（n=8）和空心钉（n=8）固定。将骨折模型置于疲劳试验机上,每组标本分别给予800 N循环轴向载荷和16 N·m循环扭转载荷3 000次,最后给予每组模型极限载荷。观察两组模型极限载荷大小。结果轴向载荷实验中,空心拉力钉锁定板组、空心钉组股骨头下沉位移分别为（0.94±0.11）mm、（1.26±0.18）mm,差异有显著统计学意义（P〈0.01）;空心拉力钉锁定板组、空心钉组极限轴向载荷分别为（3 320.00±40.23）N·m、（2 840.00±72.56）N·m,差异有显著统计学意义（P〈0.01）。扭转载荷试验中,空心拉力钉锁定板组、空心钉组股骨头扭转位移分别为（4.01±0.11）°、（6.44±0.13）°,差异有显著统计学意义（P〈0.01）。结论空心拉力钉锁定板抗侧压及抗扭转能力明显高于空心钉,在生物力学上空心拉力钉锁定板治疗股骨颈骨折有明显优势,值得临床推广使用。

Objective To explore the biomechanical differences between hollow screws and static locking plate with hollow lag screws for femoral neck fracture by testing 2 kinds of internal fixation device. Methods Sixteen sets of frozen femur specimens were selected, which included 8 males and 8 females, aged 45- 60 years old with mean age 51 years old. The femoral neck fracture models were made by femoral neck osteotomy. After anatomic reduction, the fracture samples were di-vided into 2 groups, and fixed with hollow screws（hollow screws group, n = 8） and static locking plate with hollow lag screws（static locking plate with hollow lag screws group, n = 8）. The models were placed in Zwick Z100 universal electronic material test machine and torsional testing machine（RNJ- 500）, and were given cyclic linear load 800 N, and 16 N·m cyclic torsional load 3 000 cycles. The ultimate loads of both groups were added and ultimate load data was collected. Results The displacement of hollow screws group and static locking plate with hollow lag screws group in linear testing were（0.94 ± 0.11） mm and（1.26 ± 0.18） mm, respectively, the difference was statistically significant（P〈0.01）. The limited axial load of hollow screws group and static locking plate with hollow lag screws group were（3 320.00 ± 40.23） N·m and（2 840.00 ± 72.56） N·m, respectively, the difference was statistically significant（P〈0.01）. The displacement of hollow screws group and static locking plate with hollow lag screws group in torsional testing were（4.01 ± 0.11）° and（6.44 ± 0.13）°, respectively, the difference was statistically significant（P〈0.01）. Conclusion It is demonstrated that the property of anti-linear load and torsional load of static locking plate with hollow lag screws is significantly higher than that of hollow screws. Static locking plate with hollow lag screws has biome-chanical advantages in the treatment of femoral neck fracture, which may has an application prospect in clinical practice.