强直性脊柱炎股骨近端前倾角和颈干角测量结果

Measurement outcome of femoral proximal anteversion angle and neckshaft angle in ankylosing spondylitis

背景:强直性脊柱炎(ankylosing spondylitis,AS)的股骨近端形态学参数,包括前倾角(femoral proximal anteversion angle,FPA)和颈干角(neckshaft angle,NSA),可能随脊柱-骨盆-髋关节整体结构的变化而发生改变,进而影响全髋关节置换术(total hip arthroplasty,THA)术后的生物力学机制和关节稳定性。目前相关临床研究甚少且不够深入。目的:测量AS股骨近端形态学参数结果,分析其对于THA股骨假体选择的提示意义。方法:选择2010年9月至2011年10月行THA的AS患者30例和健康对照者30例。分别通过双髋关节正位X线片和股骨CT扫描测量FPA和NSA。结果:AS组平均NSA显著高于对照组(138.00°±12.67°vs132.23°±5.88°,P=0.002),两组FPA无显著性差异(13.41°±10.02°vs11.55°±9.11°,P=0.29)。AS组中融合组平均NSA显著高于非融合组(145.29°±15.27°vs133.46°±8.07°,P<0.001),两组FPA无显著性差异(14.99°±11.08°vs12.43°±9.33°,P=0.674)。结论:AS组与对照组相比呈明显髋外翻趋势,但并未表现出FPA增大趋势。AS组中融合组患者髋外翻趋势更加明显,但FPA并未显著增大。个别AS患者FPA过大或股骨近端后倾,可能是AS自身炎症、骨化过程以及胸腰段后凸畸形继发骨盆、髋关节和膝关节代偿变化而综合影响的结果,提示AS髋关节融合的位置和角度具有较大的变异度,需要术者具体分析,选择合理的股骨假体。

Background： The morphological variables of proximal femur in patients with ankylosing spondylitis （AS）, including femo- ral proximal anteversion angle （FPA） and neckshaft angle （NSA） may alter secondary to the changes of spine-pelvis-hip in- tegrity and possibly produce an effect on the biomechanics and joint stability of hips after total hip arthroplasty （THA）. While the relevant research on documents of this subject is limited. Objective： The purpose of the study is to measure FPA and NSA in AS patients and investigate their effect on stem selection in THA. Methods： Totally 30 inpatients with AS （AS group） and 30 asymptomatic adult volunteers （control group） were included in the study. Simultaneous anteroposterior pelvic radiographs and computed tomography （CT） images of both hips were taken routinely and analyzed for FPA and NSA. Results： The average NSA in AS group was significantly higher than that in control group （138.00°± 12.67° vs 132.23°± 5.88°, P=0.002） while there was no significant difference between them for average FPA （13.41°±10.02° vs 11.55°±9.11°, p= 0.29）. For the patients with AS, the average NSA in AS group was significantly higher than that in control group （145.29°± 15.27° vs 133.46°±8.07°, P〈0.001） while there was no significant difference between them for average FPA （14.99°±11.08° vs 12.43°±9.33°, P=0.674）. Conclusions： Compared with asymptomatic adult volunteers, the patients with ankylosing spondylitis show obvious tenden- cy of increased NSA, especially for ankylosed hips while no tendency of increased FPA is seen. For ankylosed hips in patients with AS, there is wide variation of fused position and angulation, so the surgeon may need to evaluate individually and select appropriate femoral stem.