Pierrepont J, Hawdon G, Miles B P, Connor B O', Baré J, Walter L R, Marel E, Solomon M, McMahon S, Shimmin A J
The University of Sydney, School of Aerospace, Mechanical and Mechatronic Engineering, Building J07, Sydney NSW 2006, Australia and Optimized Ortho, 17 Bridge Street, Pymble NSW 2073, Australia.
Malabar Orthopaedic Clinic, 43 The Avenue, Windsor, VIC 3181, Australia.
Bone Joint J. 2017 Feb;99-B(2):184-191. doi: 10.1302/0301-620X.99B2.BJJ-2016-0098.R1.
The pelvis rotates in the sagittal plane during daily activities. These rotations have a direct effect on the functional orientation of the acetabulum. The aim of this study was to quantify changes in pelvic tilt between different functional positions.
Pre-operatively, pelvic tilt was measured in 1517 patients undergoing total hip arthroplasty (THA) in three functional positions - supine, standing and flexed seated (the moment when patients initiate rising from a seated position). Supine pelvic tilt was measured from CT scans, standing and flexed seated pelvic tilts were measured from standardised lateral radiographs. Anterior pelvic tilt was assigned a positive value.
The mean pelvic tilt was 4.2° (-20.5° to 24.5°), -1.3° (-30.2° to 27.9°) and 0.6° (-42.0° to 41.3°) in the three positions, respectively. The mean sagittal pelvic rotation from supine to standing was -5.5° (-21.8° to 8.4°), from supine to flexed seated was -3.7° (-48.3° to 38.6°) and from standing to flexed seated was 1.8° (-51.8° to 39.5°). In 259 patients (17%), the extent of sagittal pelvic rotation could lead to functional malorientation of the acetabular component. Factoring in an intra-operative delivery error of ± 5° extends this risk to 51% of patients.
Planning and measurement of the intended position of the acetabular component in the supine position may fail to predict clinically significant changes in its orientation during functional activities, as a consequence of individual pelvic kinematics. Optimal orientation is patient-specific and requires an evaluation of functional pelvic tilt pre-operatively. Cite this article: Bone Joint J 2017;99-B:184-91.
在日常活动中，骨盆会在矢状面内旋转。这些旋转对髋臼的功能方向有直接影响。本研究的目的是量化不同功能位置之间骨盆倾斜度的变化。
术前，对1517例行全髋关节置换术（THA）的患者在三个功能位置——仰卧位、站立位和屈曲坐位（患者从坐位开始起身的瞬间）测量骨盆倾斜度。仰卧位骨盆倾斜度通过CT扫描测量，站立位和屈曲坐位骨盆倾斜度通过标准化侧位X线片测量。骨盆前倾赋予正值。
三个位置的平均骨盆倾斜度分别为4.2°（-20.5°至24.5°）、-1.3°（-30.2°至27.9°）和0.6°（-42.0°至41.3°）。从仰卧位到站立位的矢状面骨盆平均旋转角度为-5.5°（-21.8°至8.4°），从仰卧位到屈曲坐位为-3.7°（-48.3°至38.6°），从站立位到屈曲坐位为1.8°（-51.8°至39.5°）。在259例患者（17%）中，矢状面骨盆旋转程度可能导致髋臼假体功能方向异常。术中植入误差±5°会使这一风险扩大至51%的患者。
由于个体骨盆运动学差异，仰卧位时髋臼假体预期位置的规划和测量可能无法预测其在功能活动期间方向的临床显著变化。最佳方向是因人而异的，术前需要评估功能性骨盆倾斜度。引用本文：《骨与关节杂志》2017年；99-B：184 - 91。
