Zhang Y L, Zhang W, Zhang C Q
Department of Orthopaedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Western Xueyuan Road, 325000 Wenzhou, China.
Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, 200233 Shanghai, China.
Orthop Traumatol Surg Res. 2017 Apr;103(2):229-234. doi: 10.1016/j.otsr.2016.11.019. Epub 2017 Jan 16.
The Pauwels angle has been used widely, however an accurate evaluation of this angle is difficult because of deformity of the affected lower extremity. Therefore we designed a new measurement of the orientation of femoral neck fracture and applied this in a retrospective study to assess: (1) its reproducibility, (2) its advantages compared with the Pauwels angle, (3) its relationship with the short-term prognosis treated with three cannulated compression screws.
This new measurement is reproducible and has some reference meaning for the treatment of femoral neck fractures.
Two hundred and twenty-eight patients with femoral neck fractures treated with three cannulated compression screws were retrospectively analyzed. The VN angle, which was the angle between the fracture line and the vertical of the neck axis, and the Pauwels angle were measured respectively. The method of ICC was performed to assess the reproducibility of the two angles, and the absolute value of difference in pre-operative and post-operative radiographs was used to evaluate the uniformity of the two angles. These fractures were divided into four groups according to VN angle (VN<0° (n=92), 0°≤VN<10° (n=82), 10°≤VN<15° (n=26), VN≥15° (n=28)), and the short-term (within 6 months) fixation results of radiographs in these fractures were evaluated.
The ICC of the VN angle and the Pauwels angle in pre-operative radiographs were 0.937 (95% confidence interval (CI): 0.922-0.950) and 0.942 respectively (95% CI: 0.914-0.970), indicating both angles had a good inter-rater reproducibility. However, there was a great difference between the Pauwels angle in pre-operative and post-operative radiographs (P=0.037), the absolute difference was 10.66±6.47 (range: 1.72-38.48), while no statistical difference for the VN angle (P=0.084) and the absolute difference was 2.20±1.63 (range: 0.05-7.56). The overall fixation failure rate which was defined as screw loosening, varus collapse, obvious fracture displacement or femoral neck shortening was 11.84%, and the mean failure rates according to VN angles were respectively 0%, 3.24% (95% CI: 1.64-4.84), 22.69% (95% CI: 16.43-28.96), 65.45% (95% CI: 59.36-71.53). The mean failure rates of fractures according to post-operative Pauwels angle (<30°, 30-50°, >50°) were respectively 0%, 1.46% (95% CI: 1.42-1.50) and 36.24% (95% CI: 34.93-37.54).
The VN angle has a good inter-rater reproducibility, a higher reliability than the Pauwels angle and is closely related to the short-term prognosis of femoral neck fractures treated with cannulated compression screws.
Level IV, retrospective diagnostic study.
Pauwels角已被广泛应用，然而由于患侧下肢畸形，对该角度进行准确评估较为困难。因此，我们设计了一种新的股骨颈骨折方向测量方法，并将其应用于一项回顾性研究中，以评估：（1）其可重复性；（2）与Pauwels角相比的优势；（3）其与采用三枚空心加压螺钉治疗的短期预后的关系。
这种新的测量方法具有可重复性，对股骨颈骨折的治疗具有一定的参考意义。
回顾性分析228例采用三枚空心加压螺钉治疗的股骨颈骨折患者。分别测量骨折线与颈轴线垂线之间的夹角VN角和Pauwels角。采用组内相关系数（ICC）法评估两个角度的可重复性，并利用术前和术后X线片上角度差异的绝对值来评估两个角度的一致性。根据VN角将这些骨折分为四组（VN<0°（n = 92），0°≤VN<10°（n = 82），10°≤VN<15°（n = 26），VN≥15°（n = 28）），并评估这些骨折的短期（6个月内）X线片固定结果。
术前X线片上VN角和Pauwels角的ICC分别为0.937（95%置信区间（CI）：0.922 - 0.950）和0.942（95% CI：0.914 - 0.970），表明两个角度均具有良好的评分者间可重复性。然而，术前和术后X线片上的Pauwels角存在较大差异（P = 0.037），绝对差值为10.66±6.47（范围：1.72 - 38.48），而VN角无统计学差异（P = 0.084），绝对差值为2.20±1.63（范围：0.05 - 7.56）。定义为螺钉松动、内翻塌陷、明显骨折移位或股骨颈缩短的总体固定失败率为11.84%，根据VN角分组的平均失败率分别为0%、3.24%（95% CI：1.64 - 4.84）、22.69%（95% CI：16.43 - 28.96）、65.45%（95% CI：59.36 - 71.53）。根据术后Pauwels角（<30°、30 - 50°、>50°）分组的骨折平均失败率分别为0%、1.46%（95% CI：1.42 - 1.50）和36.24%（95% CI：34.93 - 37.54）。
VN角具有良好的评分者间可重复性，比Pauwels角具有更高的可靠性，并且与采用空心加压螺钉治疗的股骨颈骨折的短期预后密切相关。
IV级，回顾性诊断研究。
