Institute of Biomechanics, Trauma Center Murnau, Murnau, Germany.
J Orthop Trauma. 2011 Dec;25(12):721-5. doi: 10.1097/BOT.0b013e31821146c8.
To determine whether a new femoral neck plate has a higher risk for secondary fracture after implant removal than the current standard treatment for intracapsular hip fractures.
Six pairs of human cadaver femora (age, 56 ± 5.6 years; range, 48-64 years; two female and four male donors) were instrumented with the femoral neck plate (FNP) or the compression hip screw combined with an antirotation screw (CHS) in a paired study design. After removal of the implants, axial compression tests to failure of the bones were conducted. Maximum force to failure of the bones after implant removal was determined. Axial stiffness of the bones before surgery and after implant removal was determined.
The FNP resulted in a mean failure load of 4687 ± 1743 N (mean ± standard deviation) and the CHS resulted in a mean failure load of 4892 ± 1608 N with no significant difference between the two implant groups (P = 0.405). There was no significant difference in stiffness (P = 0.214) between the FNP (1240 ± 362 N/mm) and the CHS (1293 ± 304 N/mm). The cavities left by the surgery had no effect on the bone stiffness (P > 0.05). The mean failure load of all specimens correlated with the bone mineral density in the proximal part of the femurs by R² = 0.715 (P = 0.001).
The FNP demonstrated a similar failure load after implant removal compared with the CHS, although the FNP left a 39% larger cavity in the bone.
确定新型股骨颈钢板在取出内固定物后再次骨折的风险是否高于目前治疗囊内髋部骨折的标准方法。
采用配对研究设计，对 6 对人尸体股骨（年龄 56±5.6 岁；范围 48-64 岁；2 名女性和 4 名男性供体）进行股骨颈钢板（FNP）或加压髋螺钉联合防旋螺钉（CHS）内固定。取出内固定物后，对骨骼进行轴向压缩至失效试验。测定骨骼在取出内固定物后的最大失效力。测定骨骼在手术前后的轴向刚度。
FNP 的平均失效载荷为 4687±1743N（平均值±标准差），CHS 的平均失效载荷为 4892±1608N，两组内固定物之间无显著差异（P=0.405）。FNP（1240±362N/mm）和 CHS（1293±304N/mm）之间的刚度无显著差异（P=0.214）。手术留下的空腔对骨刚度无影响（P＞0.05）。所有标本的平均失效载荷与股骨近端骨密度的相关性通过 R²=0.715（P=0.001）得到证实。
尽管 FNP 在骨内留下了 39%更大的空腔，但在取出内固定物后，其失效载荷与 CHS 相似。
