Martin J Ryan, Masonis John L, Mason J Bohannon
OrthoCarolina - Matthews, Matthews, NC, USA.
OrthoCarolina Hip and Knee Center, Charlotte, NC, USA.
Arthroplast Today. 2020 Sep 8;6(4):777-783. doi: 10.1016/j.artd.2020.07.026. eCollection 2020 Dec.
Total hip arthroplasty (THA) has demonstrated excellent results regardless of the surgical approach. However, the approach used may be a factor in final positioning of implants. We hypothesized that the direct anterior approach (DAA) with fluoroscopy would be associated with more anatomic implant positioning than the posterior approach (PA).
A retrospective review of 200 patients was performed. One hundred patients underwent THA utilizing the PA, and 100 patients, with the DAA. All patients had an anterior-posterior pelvis radiograph preoperatively and postoperatively with a magnification marker present to standardize each radiograph. Exclusion criteria included contralateral THA or any pelvic or femoral deformity.
Preoperative radiographs demonstrated identical cohorts with respect to leg length, femoral offset, and total offset. Postoperatively, the DAA achieved more accurate anatomic restoration of leg length (1.6 mm vs 5.5 mm; < .0001), femoral offset (4.8 mm vs 9.3 mm; < .0001), and total offset (0.5 mm vs 4.7 mm; < .0001) compared with the PA. Ideal cup abduction and anteversion were significantly superior to the DAA (96% vs 78%, = .0002, and 69% vs 24%, < .0001, respectively).
This study is the first to compare anatomic implant positioning between patients undergoing THA with these 2 approaches. All parameters were significantly closer to anatomic implant positioning with the DAA. There are at least 2 potential explanations for this: (1) The DAA implant positioning was performed under fluoroscopic guidance, whereas the PA was not. (2) The PA disrupts the posterior capsule and external rotators, and therefore, increased offset or leg length may be necessary to achieve comparable hip stability with the DAA.
全髋关节置换术（THA）无论采用何种手术入路，均已显示出优异的效果。然而，所采用的入路可能是影响植入物最终定位的一个因素。我们假设，与后入路（PA）相比，使用透视的直接前入路（DAA）会使植入物定位更符合解剖学要求。
对200例患者进行回顾性研究。100例患者采用PA进行THA，100例患者采用DAA。所有患者术前和术后均拍摄骨盆前后位X线片，并带有放大标记以标准化每张X线片。排除标准包括对侧THA或任何骨盆或股骨畸形。
术前X线片显示两组患者在腿长、股骨偏心距和总偏心距方面相同。术后，与PA相比，DAA在腿长（1.6 mm对5.5 mm；P<0.0001）、股骨偏心距（4.8 mm对9.3 mm；P<0.0001）和总偏心距（0.5 mm对4.7 mm；P<0.0001）的解剖学恢复方面更准确。理想的髋臼外展和前倾角在DAA组显著优于PA组（分别为96%对78%，P=0.0002；69%对24%，P<0.0001）。
本研究首次比较了采用这两种入路进行THA的患者之间植入物的解剖学定位情况。所有参数在DAA组均显著更接近植入物的解剖学定位。对此至少有两种可能的解释：（1）DAA植入物定位是在透视引导下进行的，而PA组则没有。（2）PA会破坏后关节囊和外旋肌，因此，可能需要增加偏心距或腿长才能获得与DAA相当的髋关节稳定性。
