Departments of Orthopaedic Surgery (H.I.) and Biostatistics (Y.S.), Yokohama City University School of Medicine, Yokohama, Japan.
Midwest Orthopedic Institute, Sycamore, Illinois.
J Bone Joint Surg Am. 2020 Jun 3;102(11):991-999. doi: 10.2106/JBJS.19.00300.
The spine-pelvis-hip interaction during postural change should be considered in the functional anatomy of the hip. The component parts of this anatomy and how they influence hip function are important to know. Pelvic incidence (PI) is one of these components. We studied if PI was preoperatively predictive of impingement risk and if it postoperatively influences hip position, which could cause outliers from the functional safe zone of hip replacement.
This was a prospective radiographic study of 187 consecutive patients (200 hips) who had lateral spinopelvis-hip radiographs before and after primary total hip arthroplasty with measurements of the component factors that influence mobility and position of the functional anatomy. The predictive value of PI for risk of impingement of the hip and its postoperative relationship to functional safe-zone outliers were assessed. Forty-one dislocations from our clinical practice were also reviewed.
Of 200 hips, the PI was normal in 145 hips (73%), low in 18 hips (9%), and high in 37 hips (19%). Eighty-two hips had spinopelvic imbalance: 12 (67%) of the 18 hips with low PI, 56 (39%) of the 145 hips with normal PI, and 14 (38%) of the 37 hips with high PI. Low-PI hips was the most predictive of the risk of impingement and postoperatively these hips had the most outliers from the functional safe zone.
PI is an anatomical component that is predictive of both impingement risk and functional safe-zone outliers. Preoperative risk, based on factors such as the Lewinnek zones and combined anteversion, is an established guide in determining cup position in hip replacement. Low-PI hips that have the "terrible triad" of a posteriorly tilted pelvis, stiff pelvic mobility, and increased femoral flexion therefore have no functional safe zone.
Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
在姿势改变过程中，脊柱-骨盆-髋关节的相互作用应在髋关节的功能解剖中加以考虑。了解这些解剖结构的组成部分及其对髋关节功能的影响是很重要的。骨盆入射角（PI）就是其中的一个组成部分。我们研究了 PI 是否在术前预测撞击风险，以及它是否在术后影响髋关节位置，从而导致髋关节置换的功能安全区出现异常值。
这是一项前瞻性的放射学研究，共纳入 187 例连续患者（200 髋），这些患者在初次全髋关节置换术前和术后均接受了侧位脊柱骨盆-髋关节 X 线片检查，并对影响功能解剖运动和位置的各个组成因素进行了测量。评估了 PI 对髋关节撞击风险的预测价值及其与功能安全区异常值的术后关系。我们还回顾了 41 例来自临床实践的脱位病例。
在 200 髋中，145 髋（73%）的 PI 正常，18 髋（9%）的 PI 低，37 髋（19%）的 PI 高。82 髋存在脊柱骨盆失平衡：18 髋中低 PI 的有 12 髋（67%），145 髋中正常 PI 的有 56 髋（39%），37 髋中高 PI 的有 14 髋（38%）。低 PI 髋是撞击风险的最具预测性因素，术后这些髋最容易出现功能安全区异常值。
PI 是一种解剖结构，对撞击风险和功能安全区异常值都具有预测性。基于 Lewinnek 区和联合前倾角等因素的术前风险是确定髋关节置换中杯位的既定指南。因此，具有后倾骨盆、僵硬的骨盆活动度和增加的股骨屈曲的低 PI 髋没有功能安全区。
预后 IV 级。请参阅作者说明，以获取完整的证据水平描述。
