Park Si Yong, Yang Kyu Hyun, Yoo Je Huyn, Yoon Han Kook, Park Hui Wan
Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
J Trauma. 2008 Oct;65(4):852-7. doi: 10.1097/TA.0b013e31802b9559.
Reverse obliquity intertrochanteric fractures have been recognized as having unique anatomic and mechanical characteristics. Even though some clinical reports regarding intramedullary hip nailing for reverse obliquity intertrochanteric fracture show favorable results, there has been no clinical report of intramedullary hip nailing regarding the clinical significance of the lesser trochanteric fragment which differentiates Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 31-A3.3 from A3.1 and A3.2.
We retrospectively reviewed the clinical results of 46 cases of reverse obliquity or transverse intertrochanteric fracture treated with intramedullary hip nails. Twenty-five fractures were fixed with proximal femoral nail (PFN), and 21 fractures were fixed with intertrochanteric subtrochanteric nail.
Among 40 patients, followed up for more than 6 months, 22 31-A3.3 fractures (84.6%) out of 26 and all 14 A3.1 or A3.2 fractures were healed after the first operation. The complications were four cases of fixation failure and one case of femoral shaft fracture after fall. They occurred in the A3.3 type fracture, which were fixed with the PFN. The mean union time was longer in the A3.3 group (5.98 months, range 3-17 months) compared with that in the A3.1 or A3.2 group (4.65 months, range 3-9 months) (p = 0.048). Two cases of reciprocal migration of two screws (Z-effect) required exchange of the femoral neck screw to a shorter one in the PFN group. The amount of sliding of the femoral neck screw of the PFN (6.8 mm, range 0.3 mm-16.5 mm) was greater than that of the intertrochanteric subtrochanteric nail lag screw (1.89 mm, range: 0.2 mm-4.6 mm) (p = 0.012). Statistical analysis showed that the type of implant PFN, fracture subtype (31-A3.3), and old ages (more than 65 years old) significantly prolonged the union time (p < 0.05).
The lesser trochanteric fragment and posteromedial defect in 31-A3.3 fracture seems to play an important role in the stability after intramedullary hip nailing. The causes of fixation failure in the PFN group were associated with excessive sliding of femoral neck screw, which was aggravated by toggling motion in the 31-A3.3 fractures.
反向斜行转子间骨折具有独特的解剖和力学特征。尽管一些关于髓内髋部钉治疗反向斜行转子间骨折的临床报告显示效果良好，但尚无关于髓内髋部钉治疗小转子骨折块临床意义的临床报告，小转子骨折块可区分AO/OTA 31 - A3.3型与A3.1型和A3.2型骨折。
我们回顾性分析了46例采用髓内髋部钉治疗的反向斜行或横行转子间骨折的临床结果。25例骨折采用股骨近端髓内钉（PFN）固定，21例骨折采用转子下转子间钉固定。
在40例随访超过6个月的患者中，26例中的22例31 - A3.3型骨折（84.6%）以及所有14例A3.1或A3.2型骨折在首次手术后均愈合。并发症包括4例固定失败和1例跌倒后股骨干骨折。这些并发症均发生在采用PFN固定的A3.3型骨折中。A3.3组的平均愈合时间（5.98个月，范围3 - 17个月）长于A3.1或A3.2组（4.65个月，范围3 - 9个月）（p = 0.048）。PFN组有2例出现两枚螺钉相互移位（Z效应），需要将股骨颈螺钉更换为较短的螺钉。PFN的股骨颈螺钉滑动量（6.8 mm，范围0.3 mm - 16.5 mm）大于转子下转子间钉拉力螺钉的滑动量（1.89 mm，范围：0.2 mm - 4.6 mm）（p = 0.012）。统计分析表明，植入物类型PFN、骨折亚型（31 - A3.3）和高龄（65岁以上）显著延长了愈合时间（p < 0.05）。
31 - A3.3型骨折中的小转子骨折块和后内侧缺损似乎在髓内髋部钉固定后的稳定性中起重要作用。PFN组固定失败的原因与股骨颈螺钉过度滑动有关，在31 - A3.3型骨折中，这种滑动因摆动运动而加剧。
