Imaging features of hip joint in patients with ankylosing spondylitis undergoing total hip arthroplasty

目的: 通过测量初次行人工全髋关节置换术（total hip arthroplasty，THA）的强直性脊柱炎（ankylosing spondylitis，AS）患者手术前后骨盆、髋臼及股骨相关影像学参数，初步分析其影像学特征，以期为此类患者 THA 手术方法及假体选择提供参考。. 方法: 以 2015 年 1 月—7 月初次行 THA 且符合选择标准的 AS 患者 38 例（56 髋）作为研究对象（AS 组），并以同期接受 THA 的股骨头缺血性坏死患者 36 例（45 髋）作为对照（对照组）。两组患者病变侧别比较，差异无统计学意义（ χ2=1.14， P=0.95）。所有患者术前均行髋关节 CT 扫描及三维重建，测量髋臼外展角、前倾角、中心颈干角（center collum diaphyseal，CCD）、偏心距、旋转中心至小粗隆高度以及大、小粗隆间距；术前摄 X 线片测量两组股骨髓腔开大指数（canal flare index，CFI）、皮质指数（cortical thickness index，CTI），以及 AS 组骨盆入射角（pelvic incidence，PI）、骶骨倾斜角（sacral slope，SS）、骨盆倾斜角（pelvic tilt，PT）；术后摄 X 线片测量股骨假体髓腔填充率，并测量髋臼外展角、前倾角。. Results: There was no significant difference in preoperative AVA and ABA and postoperative ABA between 2 groups ( P>0.05), but significant difference was found in postoperative AVA ( t=6.71, P=0.00). The mean PI, SS, and PT in AS group were 48.37° (range, 41-58°), 5.64°(range, 2-11°), and 12.85° (range, 5-26°), respectively. There was significant difference in CCD, CFI, and CTI between 2 groups ( t=3.63, P=0.04; t=5.12, P=0.02; t=3.91, P=0.04), but offset, HRCLT, and FID all showed no significant difference ( t=0.41, P=0.36; t=0.33, P=0.56; t=0.59, P=0.12). On the basis of the Noble classification, medullary cavity of the femur was rated as chimney type, ordinary type, and champagne flute type in 32, 18, and 6 hips of AS group, and in 4, 28, and 13 hips of control group respectively. Filling ratio of distal segment in AS group was significantly lower than that in control group ( t=5.64, P=0.02), but there was no significant difference in the filling ratio of middle and proximal segments between 2 groups ( t=0.29, P=0.61; t=0.55, P=0.13). 结论: AS 患者术前髋臼外展角、前倾角与股骨头缺血性坏死患者相比无明显差异，但术后髋臼假体前倾角明显偏大。AS 患者股骨髓腔多为烟囱型，采用锥形柄假体置换后中、远端髓腔填充率偏小，解剖型假体填充率更高。.