髋关节发育不良髋臼前后切迹的三维形态学分析

Three-dimensional morphological analysis of anterior and posterior acetabular notches in developmental dysplasia of the hip

摘要:

目的：不良的髋臼杯摆放角度显著影响全髋关节置换（total hip arthroplasty，THA）术后假体生存率，目前针对髋关节发育不良（developmental dysplasia of the hip，DDH）髋臼，缺乏可靠的术中解剖标志来辅助髋臼杯前倾的摆放，本研究分析了髋臼前后切迹相对于骨盆在三维空间内的成角特点，探讨了髋臼前后切迹对DDH THA臼杯前倾摆放的意义。方法：回顾性纳入2013年至2018年的正常人、DDH病人髋关节CT数据（正常人组22人，共44髋；DDH组66人，共117髋）。凭借髋臼前后切迹构成的连线，依据不同的前倾角定义，测量3种切迹前倾角度（手术学、放射学、解剖学），分析不同类型髋关节中每个角度与对应臼杯安全角度的关系，并探究相应角度与DDH平片学指标的联系。结果：普通髋臼组与Hartofilakidis A型 DDH髋臼组中，髋臼前后切迹在CT上均能够清晰辨认，且2组的切迹手术学前倾角（surgical anteversion of acetabular notch，SAAN）（普通髋臼：22.4°±5.5°；Hartofilakidis A型DDH髋臼：25.5°±7.4°）处于臼杯手术学前倾安全范围内（6°～36°）；在SAAN非安全的DDH髋臼组平片指标中，相较于安全组，Lateral center-edge（LCE）角更小（-2.3°±13.0° vs. 5.6°±12.3°，P=0.013），侧方脱位距离（20.9 mm vs. 15.9 mm，P=0.006）、Tonnis角（35.4° vs. 30.8°，P=0.005）更大。结论：髋臼前后切迹在正常或低脱位型DDH髋臼中CT识别率高，可以作为术中一个特定的解剖标志。对于发育正常髋臼与Hartofilakidis A型DDH髋臼的全髋关节置换术，从骨盆矢状位来看，髋臼前后切迹可以作为髋臼杯前倾摆放的良好解剖参考标志。SAAN臼杯前倾定位法应避免在平片显示LCE角显著减小，侧方脱位距离、Tonnis角显著增大的髋关节中使用。

Abstract:

Objective：Inappropriate acetabular cup placement significantly affects implant survival following total hip arthroplasty （THA）. However，there is a current lack of reliable intraoperative landmarks for guiding the anteversion placement of the acetabular cup during THA for developmental dysplasia of the hip（DDH）. In this study，we analyzed the morphological characteristics of the anterior and posterior acetabular notches（APANs） using three-dimensional（3D） computed tomography（CT） and assessed its potential as a safe reference landmark for anteversion cup placement in THA for DDH. Methods：The 3D-CT data of 22 healthy controls（44 hips） and 66 DDH patients（117 hips） between 2013 to 2018 were reviewed. Three anteversion angles defined by surgery，anatomy，and radiology were measured based on the line connecting the APANs. The relationships between each angle and the corresponding safe cup zone and between the angle and plain radiographic parameters in different hip types were analyzed. Results：The APANs could be clearly identified by CT，and the surgical anteversion of acetabular notch（SAAN） was within the safe zone（6°-36°） for both controls（22.4°±5.5°） and Hartofilakidis A DDH patients（25.5°±7.4°）. Compared with DDH patients with safe SAAN，those with unsafe SAAN had smaller lateral center-edge angle（5.6°±12.3° vs. -2.3°±13.0°，P=0.013），greater lateral subluxation（15.9 mm vs. 20.9 mm，P=0.006），and greater Tonnis angle（30.8° vs. 35.4°，P=0.005）. Conclusion：APANs can be easily identified by CT in healthy controls and Hartofilakidis A DDH patients，and may thereby serve as a good anatomical reference landmark for anteversion cup placement in sagittal view of the pelvis. SAAN-guided antever－sion cup placement should be avoided in DDH patients with reduced LCE angle，increased lateral subluxation，and increased Tonnis angle indicated by plain radiograph.