T. Tachibana, M. Fujii, K. Kitamura, Y. Nakashima, Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka Japan T. Nakamura, Department of Orthopaedic Surgery, Japan Community Health Care Organization, Kyushu Hospital, Kitakyushu, Japan.
Clin Orthop Relat Res. 2019 Nov;477(11):2455-2466. doi: 10.1097/CORR.0000000000000898.
Although variation in physiologic pelvic tilt may affect acetabular version and coverage, postural change in pelvic tilt in patients with hip dysplasia who are candidates for hip preservation surgery has not been well characterized, and its clinical importance is unknown.
QUESTIONS/PURPOSES: The aim of this study was to determine (1) postural changes in sagittal pelvic tilt between the supine and standing positions; (2) postural changes in the acetabular orientation and coverage of the femoral head between the supine and standing positions; and (3) patient demographic and morphologic factors associated with sagittal pelvic tilt.
Between 2009 and 2016, 102 patients underwent pelvic osteotomy to treat hip dysplasia. All patients had supine and standing AP pelvic radiographs and pelvic CT images taken during their preoperative examination. Ninety-five patients with hip dysplasia (lateral center-edge angle < 20°) younger than 60 years old were included. Patients with advanced osteoarthritis, other hip disease, prior hip or spine surgery, femoral head deformity, or inadequate imaging were excluded. Sixty-five patients (64%) were eligible for participation in this retrospective study. Two board-certified orthopaedic surgeons (TT and MF) investigated sagittal pelvic tilt, spinopelvic parameters, and acetabular version and coverage using pelvic radiographs and CT images. Intra- and interobserver reliabilities, evaluated using the intraclass correlation coefficient (0.90 to 0.98, 0.93 to 0.99, and 0.87 to 0.96, respectively), were excellent. Demographic data (age, gender, and BMI) were collected by medical record review. Sagittal pelvic tilt was quantified as the angle formed by the anterior pelvic plane and a z-axis (anterior pelvic plane angle). Using a 2D-3D matching technique, we measured the change in sagittal pelvic tilt, acetabular version, and three-dimensional coverage between the supine and standing positions. We correlated sagittal pelvic tilt with demographic and CT measurement parameters using Pearson's or Spearman's correlation coefficients.
Although functional pelvic tilt varied widely among individuals, the pelvis of patients with hip dysplasia tilted posteriorly from the supine to the standing position (mean APP angle 8° ± 6° versus 2° ± 7°; mean difference -6°; 95% CI, -7° to -5°; range -17° to 4.1°; p < 0.001; paired t-test).The pelvis tilted more than 5° posteriorly from the supine to the standing position in 39 patients (60%), and the change was greater than 10° in 12 (18%). In the latter subgroup of patients, the mean acetabular anteversion angle increased (22° ± 5° versus 27° ±5°; mean difference 5°; 95% CI, 4°-6°; p < 0.001) and the mean anterosuperior acetabular sector angle notably deceased from the supine to the standing position (91° ± 11° versus 77° ± 14°; mean difference -14°; 95% CI, -17° to -11°; p < 0.001; paired t-test). Postural change in pelvic tilt was not associated with any of the studied demographic or morphologic parameters, including patient age, gender, BMI, and acetabular version and coverage.
On average, the pelvis tilted posteriorly from the supine to the standing position in patients with hip dysplasia, resulting in increased acetabular version and decreased anterosuperior acetabular coverage in the standing position. Thus, assessment with a supine AP pelvic radiograph may overlook changes in acetabular version and coverage in weightbearing positions. We recommend assessing postural change in sagittal pelvic tilt when diagnosing hip dysplasia and planning hip preservation surgery. Further studies are needed to determine how postural changes in sagittal pelvic tilt affect the biomechanical environment of the hip and the clinical results of acetabular reorientation osteotomy.
Level IV, diagnostic study.
尽管生理骨盆倾斜度的变化可能会影响髋臼的倾斜度和覆盖度，但髋关节发育不良患者在髋关节保存手术候选者中骨盆倾斜度的姿势变化尚未得到很好的描述，其临床意义尚不清楚。
本研究旨在确定（1）仰卧位与站立位之间矢状面骨盆倾斜度的姿势变化；（2）仰卧位与站立位之间髋臼方位和股骨头覆盖度的姿势变化；（3）与矢状面骨盆倾斜度相关的患者人口统计学和形态学因素。
2009 年至 2016 年期间，有 102 例患者接受骨盆截骨术治疗髋关节发育不良。所有患者均在术前检查中接受了仰卧位和站立位骨盆正位片和骨盆 CT 图像。共纳入 95 例年龄小于 60 岁的髋关节发育不良患者（外侧中心边缘角<20°）。排除了晚期骨关节炎、其他髋关节疾病、既往髋关节或脊柱手术、股骨头畸形或影像学不充分的患者。65 例患者（64%）符合本回顾性研究的纳入标准。两名具有资质的骨科医生（TT 和 MF）使用骨盆 X 线片和 CT 图像研究了矢状面骨盆倾斜度、脊柱骨盆参数以及髋臼倾斜度和覆盖度。采用组内相关系数（0.90 至 0.98、0.93 至 0.99 和 0.87 至 0.96）评估了测量的重复性，结果均为优秀。通过病历回顾收集了人口统计学数据（年龄、性别和 BMI）。矢状面骨盆倾斜度通过前骨盆平面和 z 轴（前骨盆平面角）形成的角度来量化。使用 2D-3D 匹配技术，我们测量了仰卧位与站立位之间矢状面骨盆倾斜度、髋臼倾斜度和三维覆盖度的变化。我们使用 Pearson 或 Spearman 相关系数将矢状面骨盆倾斜度与人口统计学和 CT 测量参数相关联。
尽管功能性骨盆倾斜度在个体之间差异很大，但髋关节发育不良患者的骨盆从仰卧位向站立位向后倾斜（平均 APP 角 8°±6°与 2°±7°；平均差异-6°；95%置信区间-7°至-5°；范围-17°至 4.1°；p<0.001；配对 t 检验）。39 例（60%）患者的骨盆从仰卧位向后倾斜超过 5°，12 例（18%）患者的变化超过 10°。在后一组患者中，髋臼前倾角增加（22°±5°与 27°±5°；平均差异 5°；95%置信区间 4°-6°；p<0.001），仰卧位时前上髋臼区域角度明显减小（91°±11°与 77°±14°；平均差异-14°；95%置信区间-17°至-11°；p<0.001；配对 t 检验）。骨盆倾斜度的姿势变化与研究的任何人口统计学或形态学参数均无关，包括患者年龄、性别、BMI、髋臼倾斜度和覆盖度。
髋关节发育不良患者的骨盆从仰卧位向站立位向后倾斜，导致站立位时髋臼倾斜度增加，前上髋臼覆盖度减小。因此，在负重位时，仰卧位骨盆正位 X 线片可能会忽略髋臼倾斜度和覆盖度的变化。我们建议在诊断髋关节发育不良和计划髋关节保存手术时评估矢状面骨盆倾斜度的姿势变化。需要进一步研究以确定矢状面骨盆倾斜度的姿势变化如何影响髋关节的生物力学环境以及髋臼再定向截骨术的临床结果。
IV 级，诊断研究。
