Department of Pediatric Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA.
Department of Hip Preservation, Hospital for Special Surgery, New York, NY, USA.
Clin Orthop Relat Res. 2024 Sep 1;482(9):1659-1667. doi: 10.1097/CORR.0000000000003031. Epub 2024 Apr 2.
There are few data on the impact of periacetabular osteotomy (PAO) on sagittal spinopelvic alignment. Prior studies have attempted to delineate the relationship by performing measurements on AP radiographs and using mathematical models to determine changes in postoperative pelvic tilt. This information is clinically significant to a surgeon when evaluating acetabular/pelvic position intraoperatively and understanding spinopelvic alignment changes postoperatively; therefore, radiographic changes from PAO should be described in more detail.
QUESTIONS/PURPOSES: In this study, we asked: (1) Does the performance of PAO result in consistent changes in spinopelvic alignment, as measured on EOS radiographs? (2) Does this differ for unilateral versus bilateral PAOs? (3) Does this differ in the setting of a mobile spine versus an immobile spine? (4) Does this differ based on preoperative pelvic tilt?
Mean preoperative and at least 1-year postoperative (15 ± 8 months from surgery, minimum 11 months, maximum 65 months) EOS hip-to-ankle standing and sitting radiographs for 55 patients in a prospectively collected registry who underwent PAO with a single surgeon from January 1, 2019, to January 11, 2022, were measured for pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, lateral center-edge angle, L1 pelvic angle, and pubic symphysis to the sacroiliac index. Normality was assessed and paired sample t-tests (normally distributed data) or Wilcoxon signed rank tests (not normally distributed data) were utilized to assess if any measurements changed from preoperative to postoperative. Patients were then divided based on whether they had unilateral or bilateral dysplasia and unilateral or bilateral surgery, and these subgroups were analyzed the same way as the entire cohort. Two more subgroups were then formed based on lumbar mobility, defined as a change in sitting-to-standing lumbar lordosis less or greater than 1 SD from the population mean preoperatively, and the subgroups were analyzed the same way as the entire cohort. Finally, two additional subgroups were formed, preoperative standing pelvic tilt less than 10° and more than 20°, and analyzed the same as the entire cohort.
For the entire cohort, the median (IQR) standing lateral-center edge angle increased 17°, from a median of 21° (10°) to a median of 38° (8° [95% confidence interval (CI) 16° to 20°; p < 0.001). The median sitting lateral center-edge angle increased 17°, from a median of 18° (8°) to a median of 35° (8° [95% CI 14° to 19°]; p < 0.001). Standing pelvic incidence increased from 50° ± 11° to 52° ± 12° (mean difference 2° [95% CI 1° to 3°]; p = 0.004), but there were no changes for other measured parameters. There were no changes in any of the spinopelvic parameters for patients with unilateral dysplasia receiving a unilateral PAO, but patients with bilateral dysplasia who underwent bilateral PAOs demonstrated an increase in pelvic incidence from 57° (14°) to 60° (16°) (95% CI 1° to 5°; p = 0.02) and a decrease in pubic symphysis to sacroiliac index from 84 mm (24 mm) to 77 mm (23 mm) (95% CI -7° to -2°; p = 0.007). Patients with mobile lumbar spines preoperatively did not exhibit any changes in sagittal spinopelvic alignment, but patients with immobile lumbar spines preoperatively experienced several changes after surgery. Patients with less than 10° of standing pelvic tilt demonstrated a median (IQR) 2° increase in pelvic incidence from median 43° (9°) to 45° (12° [95% CI 0.3° to 4°]; p = 0.03), but they did not experience any other changes in sagittal spinopelvic alignment parameters postoperatively. Patients with preoperative pelvic tilt more than 20° did not experience any change in sagittal spinopelvic parameters.
PAO increases pelvic incidence, potentially because of anterior translation of the hip center. There were no changes in other spinopelvic parameters postoperatively except after bilateral PAO. Additionally, patients lacking spine mobility preoperatively, indicated by a minimal change in lumbar lordosis between standing and sitting positions, may experience several changes in spinopelvic alignment, including increased mobility of their spine after PAO. This may be because of decreased compensatory spine splinting after increasing acetabular coverage, but further research including patient-reported outcomes is warranted.
Level III, therapeutic study.
目前关于髋臼周围截骨术（PAO）对矢状位骨盆脊柱排列影响的数据较少。先前的研究试图通过对骨盆前后位 X 线片进行测量，并使用数学模型来确定术后骨盆倾斜的变化，以此来描绘两者之间的关系。当术者术中评估髋臼/骨盆位置和理解术后脊柱骨盆排列变化时，这些信息对术者具有重要的临床意义；因此，PAO 后的影像学变化应更详细地描述。
问题/目的：在这项研究中，我们提出了以下问题：（1）PAO 是否会导致骨盆脊柱矢状位排列的一致变化，这可以通过 EOS 射线照相术测量？（2）对于单侧或双侧 PAO，这种变化是否存在差异？（3）对于活动度或非活动度脊柱，这种变化是否存在差异？（4）这种变化是否基于术前骨盆倾斜度？
前瞻性收集了 2019 年 1 月 1 日至 2022 年 1 月 11 日期间由同一位外科医生进行的 PAO 手术的 55 例患者的术前和至少 1 年（手术 15 ± 8 个月，最短 11 个月，最长 65 个月）EOS 髋关节到踝关节的站立和坐姿射线照片，用于测量骨盆入射角、骨盆倾斜度、骶骨倾斜度、腰椎前凸度、侧中心边缘角、L1 骨盆角和耻骨联合到骶髂关节指数。评估正态性，然后使用配对样本 t 检验（正态分布数据）或 Wilcoxon 符号秩检验（非正态分布数据）来评估任何测量值是否从术前到术后发生变化。然后，根据患者是否存在单侧或双侧发育不良以及单侧或双侧手术将患者进行分组，并对这些亚组进行与整个队列相同的分析。然后根据术前站立时腰椎活动度（站立位到坐位腰椎前凸度的变化小于或大于人群平均值的 1 个标准差）将两个亚组进一步分组，并对整个队列进行相同的分析。最后，根据术前站立时骨盆倾斜度小于 10°或大于 20°形成两个额外的亚组，并与整个队列进行相同的分析。
对于整个队列，站立时侧中心边缘角的中位数（IQR）增加了 17°，从中位数 21°（10°）增加到中位数 38°（8° [95%置信区间 16°至 20°]；p < 0.001）。坐立时侧中心边缘角的中位数增加了 17°，从中位数 18°（8°）增加到中位数 35°（8° [95%置信区间 14°至 19°]；p < 0.001）。站立时骨盆入射角从 50°±11°增加到 52°±12°（平均差异 2° [95%置信区间 1°至 3°]；p = 0.004），但其他测量参数没有变化。对于接受单侧 PAO 的单侧发育不良患者，任何脊柱骨盆参数均无变化，但接受双侧 PAO 的双侧发育不良患者的骨盆入射角从 57°（14°）增加到 60°（16°）（95%置信区间 1°至 5°；p = 0.02），耻骨联合到骶髂关节指数从 84 mm（24 mm）减少到 77 mm（23 mm）（95%置信区间 -7°至 -2°；p = 0.007）。术前腰椎活动度较大的患者的矢状位脊柱骨盆排列没有变化，但术前腰椎活动度较小的患者术后经历了多种变化。术前站立时骨盆倾斜度小于 10°的患者的骨盆入射角中位数（IQR）从中位数 43°（9°）增加到 45°（12° [95%置信区间 0.3°至 4°]；p = 0.03），但术后其他矢状位脊柱骨盆排列参数没有变化。术前骨盆倾斜度大于 20°的患者的矢状位脊柱骨盆参数没有变化。
PAO 会增加骨盆入射角，这可能是由于髋关节中心的前向移位。除了双侧 PAO 后，术后其他脊柱骨盆参数没有变化。此外，术前脊柱活动度较小的患者（站立位到坐位腰椎前凸度的变化小于 1 个标准差）可能会经历几种脊柱骨盆排列的变化，包括术后髋关节覆盖增加后脊柱活动度的增加。这可能是因为增加髋臼覆盖后，脊柱代偿性固定减少，但需要进一步的包括患者报告的结果的研究。
III 级，治疗性研究。
