侧卧位时头尾侧骨盆倾斜对全髋关节置换髋臼杯外展角的影响及校正

 目的 探讨侧卧位时骨盆向头尾侧倾斜的程度及其对髋关节置换术中髋臼假体外展角的影响及校正方法。方法 将50例62髋拟行全髋关节置换术的患者随机分为校正组及对照组，均采用侧卧位后外侧入路手术。对照组25例28髋以常规方法放置髋臼假体，校正组25例34髋进行水平仪及铅垂法校正后放置髋臼假体。术后测量两组患者髋臼杯外展角，并比较与术中预估的差异。结果 校正组在侧卧位未校正前骨盆整体倾斜-1.647°±4.512°，向头侧倾斜-(4.989°±2.778°)，向尾侧倾斜2.587°±1.927°；头侧倾斜偏离大于尾侧，差异有统计学意义。校正组术后髋臼杯外展角为42.685°±3.355°，术中预估与术后测量偏差1.962°±1.515°；对照组术后髋臼杯外展角为44.534°±4.844°，术中预估与术后测量偏差4.244°±3.042°；校正组偏差小于对照组，差异有统计学意义。结论 侧卧位时头尾侧骨盆倾斜影响术者对髋臼外展角的判断，可能造成髋臼假体放置角度不准确。通过水平仪及铅垂法进行校正可提高判定髋臼假体外展角的准确性。

Influence of pelvic obliquity in lateral position to acetabular component orientation during total hip arthroplasty

Objective To explore the influence of pelvis obliquity in lateral position to acetabular component orientation during total hip arthroplasty (THA), and the method to correct. Methods Fifty patients (62 hips) were performed THA with posterolateral incision in lateral position by the same team. The patients were randomized and divided into experimental group (EX, with 25 cases, 34 hips) and control group (CON, with 25 cases, 28 hips). In EX group, the acetabular components were placed by means of the gradienter and plumb correcting technique during THA. While in CON group, the acetabular components were placed by traditional method during THA. The acetabular abduction angles were measured postoperatively, and compared between the two groups. Results The average obliquity of pelvis was -1.647°±4.512° in EX group when putting the patient in lateral position before correcting. Through the application of gradienter and plumb, the average abduction angle of acetabular component was 42.685°±3.355° postoperatively, with the difference of 1.962°±1.515° compared with the preoperative angles. And in CON group, the average abduction angle of acetabular component was 44.534°±4.844° postoperatively, with the difference of 4.244°±3.042°. The difference of abduction angle in CON group was much higher than that in EX group(P<0.05). Conclusion The pelvic obliquity when putting the patient under lateral position will affect the surgeons' judgments of placing acetabular component during THA, furthermore, lead to inconsistency among the abduction angles obtained preoperatively, intraoperatively and postoperatively. By applying the correcting method with gradienter and plumb, the discrepancy can reduce obviously between the abduction angle measured postoperatively and that of measured during operation comparing with traditional method.