Department of Orthopaedic Surgery, Baylor Univeristy Medical Center, Dallas, TX.
W.B. Carrell Memorial Clinic, Adult Hip and Knee Reconstruction, Dallas, TX; Department of Orthopaedic Surgery, Texas Health Presbyterian Hospital Dallas, Dallas, TX.
J Arthroplasty. 2021 Nov;36(11):3692-3696. doi: 10.1016/j.arth.2021.07.003. Epub 2021 Jul 14.
Pelvic tilt affects acetabular anteversion, and thus total hip arthroplasty (THA) dislocation risk. The pubic symphysis-sacrococcygeal distance (PSCD) is an indicator of pelvic tilt, and a PSCD < 0 mm (ie, excessive posterior pelvic tilt) is associated with a 3.7-fold increase in postoperative dislocation rate. However, it is not known if the direct anterior (DA) approach might reduce this dislocation rate, specifically in high-risk populations such as negative PSCD.
Standing anteroposterior radiographs were reviewed for 510 consecutive DA THAs to determine PSCD. Patients were separated into 2 groups: (1) PSCD > 0 mm (PSCD[+]) and (2) PSCD < 0 mm (PSCD[-]). Incidence of dislocation was determined. We recorded if patients had spinal deformity or lumbar fusion. Continuous variables were analyzed using Student's t-test, categorical variables were analyzed using Fisher's exact test, and a sample size calculation was performed.
Three hundred fifty-eight hips (70.2%) were PSCD[+], while 152 hips (29.8%) were PSCD[-]. Three dislocations (3/510 hips, 0.6%) occurred. Two dislocators were in the PSCD[-] group (2/152 hips, 1.3%) and 1 dislocator was in the PSCD[+] group (1/358 hips, 0.3%) (P = .21). Twenty-four patients had degenerative scoliosis (24/510, 4.7%), of which 1 had a dislocation (1/24, 4.2%); 2 dislocations occurred in nonscoliosis patients (2/486, 0.4%) (P = .134). Twenty-seven patients had lumbar spinal fusion (27/510, 5.3%), of which there were no dislocations (0/27, 0.0%); all dislocations were in nonfusion patients (3/483, 0.6%) (P = 1.0).
We demonstrate no increased risk for THA dislocation in patients with a PSCD < 0 mm who have undergone a DA approach. These data would suggest a protective effect of the DA approach against dislocation, even in historically high-risk populations.
骨盆倾斜会影响髋臼前倾角，从而影响全髋关节置换术（THA）脱位的风险。耻骨联合-尾骨距离（PSCD）是骨盆倾斜的一个指标，PSCD<0 毫米（即骨盆过度后倾）与术后脱位率增加 3.7 倍有关。然而，目前尚不清楚直接前入路（DA）是否可以降低这种脱位率，特别是在 PSCD 为负的高危人群中。
对 510 例连续行 DA-THA 的患者进行站立前后位 X 线片复查，以确定 PSCD。患者分为两组：（1）PSCD>0 毫米（PSCD[+]）和（2）PSCD<0 毫米（PSCD[-]）。确定脱位的发生率。我们记录患者是否有脊柱畸形或腰椎融合。连续变量采用 Student t 检验进行分析，分类变量采用 Fisher 精确检验进行分析，并进行样本量计算。
358 髋（70.2%）PSCD[+]，152 髋（29.8%）PSCD[-]。发生 3 例脱位（510 髋，0.6%）。2 例脱位者在 PSCD[-]组（152 髋，1.3%），1 例脱位者在 PSCD[+]组（358 髋，0.3%）（P=0.21）。24 例患者有退行性脊柱侧凸（24/510，4.7%），其中 1 例发生脱位（24/24，4.2%）；2 例脱位发生在无脊柱侧凸患者（486 髋，0.4%）（P=0.134）。27 例患者有腰椎融合（27/510，5.3%），无脱位（27/27，0.0%）；所有脱位均发生在非融合患者（483 髋，0.6%）（P=1.0）。
我们的研究表明，行 DA 入路的 PSCD<0 毫米患者行 THA 后脱位风险无增加。这些数据表明，DA 入路对脱位有保护作用，即使在既往高危人群中也是如此。
