Center for Joint Preservation & Reconstruction, NorthshoreLIJ/Lenoxhill Hospital, 130 E 77th Street, 11th Floor, New York, NY, 10075, USA,
Clin Orthop Relat Res. 2014 Jun;472(6):1877-85. doi: 10.1007/s11999-014-3512-2. Epub 2014 Feb 19.
The direct anterior approach for THA offers some advantages, but is associated with a significant learning curve. Some of the technical difficulties can be addressed by the use of intraoperative fluoroscopy which may improve the accuracy of acetabular component placement.
QUESTIONS/PURPOSES: The purposes of this study were to determine if (1) there is decreased variability of acetabular cup inclination and anteversion with the direct anterior approach using fluoroscopic guidance as compared with the posterior approach THA without radiographic guidance; (2) if there is a learning curve associated with achieving accuracy with the direct anterior approach THA. We also wanted (3) to assess the frequency of complications including dislocation with the anterior approach, which initially had a learning curve, and the posterior approach.
This retrospective, comparative study of 825 THAs (372 posterior THAs without fluoroscopic guidance and 453 direct anterior THAs, performed by one surgeon, focused on a radiographic analysis to determine cup inclination and anteversion on standardized pelvic radiographs using specialized software. The first 100 direct anterior THAs performed while transitioning from the posterior approach to the direct anterior approach were included in the learning curve group. During this learning curve period, the direct anterior approach was used for all patients except those with conversion of previously fixed intertrochanteric or femoral neck fractures to THAs, gluteus medius tears, and obese patients with an immobile abdominal pannus (100 of 127 THAs). Variability of the acetabular component was compared among the posterior group, learning curve group, and direct anterior group.
Variances for cup inclination and anteversion were significantly lower in the direct anterior group (19 and 16 respectively, p < 0.01) as compared with the posterior group (50 and 79 respectively).Target inclination and anteversion were achieved better in the direct anterior group (98% and 97% respectively) as compared with the posterior group (86% and 77% respectively) (p < 0.01, OR for inclination = 9.1, 95% CI, 3.5 to 23.4; OR for anteversion = 8, 95% CI, 4 to 16). In the learning curve group, target anteversion achieved (91% of cases) was marginally lower than that of the direct anterior group (p = 0.03; OR = 2.9, 95% CI, 1.1 to 7.3) and target inclination (95%) was similar (p = 0.13). There was one posterior dislocation in the posterior group, two anterior dislocations in the learning curve group, and none in the direct anterior group.
Use of fluoroscopy with the patient in the supine position during direct anterior THA enables intraoperative assessment of cup orientation resulting in decreased variability of acetabular cup anteversion. However, there is a learning curve associated with achieving this accuracy. We could not discern whether this difference was the result of the approach or the use of fluoroscopy in the direct anterior group.
Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.
直接前路髋关节置换术（THA）具有一些优势，但存在明显的学习曲线。术中使用透视可以解决一些技术难题，这可能会提高髋臼假体放置的准确性。
问题/目的：本研究旨在确定：（1）与后路 THA 相比，在直接前路 THA 中使用透视引导是否可以降低髋臼杯倾斜和前倾角的变异性；（2）直接前路 THA 达到准确性是否存在学习曲线。我们还希望评估与前路相关的并发症（包括脱位）的发生率，前路在学习曲线阶段存在一定难度，后路也会出现并发症。
本研究回顾性比较了 825 例 THA（372 例后路无透视引导和 453 例直接前路，由同一位医生完成），重点进行了影像学分析，使用专用软件在标准骨盆 X 线片上确定髋臼杯的倾斜度和前倾角。最初存在学习曲线的 100 例直接前路 THA 纳入学习曲线组。在此学习曲线阶段，除了将先前固定的转子间或股骨颈骨折转换为 THA、臀中肌撕裂以及肥胖患者伴有不可移动的腹部赘肉的患者（127 例中的 100 例）外，所有患者均采用直接前路入路。比较后路组、学习曲线组和直接前路组髋臼假体的变异性。
直接前路组髋臼杯倾斜度和前倾角的方差明显低于后路组（分别为 19 和 16，p < 0.01）。直接前路组的目标倾斜度和前倾角（分别为 98%和 97%）明显优于后路组（分别为 86%和 77%）（p < 0.01，倾斜度的优势比为 9.1，95%可信区间为 3.5 至 23.4；前倾角的优势比为 8，95%可信区间为 4 至 16）。在学习曲线组中，达到的目标前倾角（91%的病例）略低于直接前路组（p = 0.03；优势比 = 2.9，95%可信区间为 1.1 至 7.3），而目标倾斜度（95%）相似（p = 0.13）。后路组发生 1 例后脱位，学习曲线组发生 2 例前脱位，直接前路组均未发生。
在直接前路 THA 中，使用透视引导患者仰卧位，可以在术中评估髋臼假体的方向，从而降低髋臼杯前倾角的变异性。但是，达到这种准确性存在学习曲线。我们无法确定这种差异是由于手术入路还是直接前路组使用透视造成的。
III 级，治疗研究。有关证据等级的完整描述，请参见作者说明。
