Hélin M, Pelissier A, Boyer P, Delory T, Estellat C, Massin P
Département de chirurgie orthopédique, hôpitaux universitaires Paris Nord Val-de-Seine, site Bichat, 46, rue Henri-Huchard, 75877 Paris cedex 18, France; Université Paris Diderot, Sorbonne Paris Cité, EA REMES, 75010 Paris, France.
Département de biostatistiques, hôpitaux universitaires Paris Nord Val-de-Seine, site Bichat, 46, rue Henri-Huchard, 75877 Paris cedex 18, France.
Orthop Traumatol Surg Res. 2015 Feb;101(1):45-9. doi: 10.1016/j.otsr.2014.11.009. Epub 2015 Jan 9.
Femoral neck shortening after dynamic fixation of extra-capsular fracture may impair functional results, but is rarely assessed. The present study measured impaction in stable and unstable fractures (on the Ender classification) treated by PFNA™ nail. The objectives were: 1) to validate the Ender classification to assess fracture stability; 2) to determine whether neck shortening and head purchase quality varied with stability; and 3) to determine the functional impact of femoral neck shortening.
The study hypothesis was that the PFNA™ nail stabilizes unstable as well as stable fractures.
One hundred and fifteen consecutive patients, aged over 70 years, operated on for intertrochanteric fracture using the PFNA™ nail were followed up prospectively for 6 months. Multivariate analysis, including age, gender, assembly quality and body-mass index, was applied to assess the predictive power of the Ender classification with respect to femoral neck shortening. Secondly, patients were grouped according to stable versus unstable fracture (n=70 and 45, respectively), and impaction and femoral head purchase were assessed on a dedicated radiographic protocol. Functional results were assessed on Parker score.
In the unstable fracture group, 3 assembly failures required revision by total hip replacement. Ender grade>2 was significantly predictive of>5mm neck shortening. Neck shortening was greater in unstable fracture: 8.1 ± 8.4mm (range, 4-32 mm), versus 2.5 ± 3.7 mm (range, 3-14 mm) (P=0.0004). Mean blade cut-through was 1.2 ± 2.9 mm (range, 1-12 mm) in unstable fracture, versus 0.3 ± 1.3 mm (range, 1-6mm) (P=0.02). Mean cut-out was 2.3 ± 6 mm (range, 2-21 mm) in unstable fracture, versus 0.5 ± 2.6 mm (range, 1-8mm) (P=0.03). Parker scores diminished comparably in the two groups, without significant difference at follow-up: 3.9 ± 2.6 (range, 0-9) in stable and 3.1 ± 1.9 (range, 0-8) in unstable fracture; reduction in Parker score showed no correlation with femoral neck shortening (r=0.013, P=0.88).
The PFNA™ nail provides poorer stabilization of unstable compared to stable fracture. Femoral neck shortening should be taken into account in assessing internal fixation hardware perfomances.
Level III. Prospective case-control study.
囊外骨折动态固定后股骨颈缩短可能会影响功能结果，但很少被评估。本研究测量了采用PFNA™髓内钉治疗的稳定和不稳定骨折（根据恩德尔分类法）中的骨块嵌插情况。目的如下：1）验证恩德尔分类法以评估骨折稳定性；2）确定股骨颈缩短和股骨头把持质量是否随稳定性而变化；3）确定股骨颈缩短对功能的影响。
本研究的假设是PFNA™髓内钉能稳定不稳定骨折和稳定骨折。
对115例年龄超过70岁、采用PFNA™髓内钉治疗转子间骨折的连续患者进行了为期6个月的前瞻性随访。应用多因素分析，包括年龄、性别、组装质量和体重指数，以评估恩德尔分类法对股骨颈缩短的预测能力。其次，根据骨折稳定与否将患者分组（分别为70例和45例），并通过专门的影像学方案评估骨块嵌插和股骨头把持情况。根据帕克评分评估功能结果。
在不稳定骨折组中，3例组装失败需要行全髋关节置换翻修术。恩德尔分级>2对股骨颈缩短>5mm具有显著预测性。不稳定骨折中的股骨颈缩短更明显：8.1±8.4mm（范围4 - 32mm），而稳定骨折中为2.5±3.7mm（范围3 - 14mm）（P = 0.0004）。不稳定骨折中的平均刀片切入深度为1.2±2.9mm（范围1 - 12mm），而稳定骨折中为0.3±1.3mm（范围1 - 6mm）（P = 0.02）。不稳定骨折中的平均穿出深度为2.3±6mm（范围2 - 21mm），而稳定骨折中为0.5±2.6mm（范围1 - 8mm）（P = 0.03）。两组的帕克评分均有类似下降，随访时无显著差异：稳定骨折组为3.9±2.6（范围0 - 9），不稳定骨折组为3.1±1.9（范围0 - 8）；帕克评分的降低与股骨颈缩短无相关性（r = 0.013，P = 0.88）。
与稳定骨折相比，PFNA™髓内钉对不稳定骨折的固定效果较差。在评估内固定器械性能时应考虑股骨颈缩短情况。
III级。前瞻性病例对照研究。
