Shin Chang Ho, Yang Eunkyu, Lim Chaemoon, Yoo Won Joon, Choi In Ho, Cho Tae-Joon
C. H. Shin, E. Yang, C. Lim, W. J. Yoo, I. H. Choi, T-J. Cho, Division of Pediatric Orthopaedics, Seoul National University Children's Hospital, Seoul, Republic of Korea.
Clin Orthop Relat Res. 2020 Sep;478(9):2120-2131. doi: 10.1097/CORR.0000000000001289.
The acetabular index and center-edge angle are widely used radiographic parameters. However, the exact landmarks for measuring these parameters are not clearly defined. Although their measurement is straightforward when the lateral osseous margin of the acetabular roof coincides with the lateral end of the acetabular sourcil, where these two landmarks disagree, recommendations have differed about which landmark should be used. Using a radiographic parameter with high reliability for predicting residual hip dysplasia helps avoid unnecessary treatment.
QUESTIONS/PURPOSES: We aimed to (1) compare two landmarks (the lateral osseous margin of the acetabular roof and the lateral end of the acetabular sourcil) for measuring the acetabular index and center-edge angle with respect to intraobserver and interobserver reliability and the predictability of residual hip dysplasia in patients with developmental dysplasia of the hip (DDH) and (2) evaluate longitudinal change in the acetabular edge's shape after closed reduction with the patient under general anesthesia.
Between February 1985 and July 2006, we performed closed reduction with the patient under general anesthesia as well as cast immobilization in 116 patients with DDH. To be included in this study, a patient had to have dislocated-type DDH. We excluded patients with a hip dislocation associated with neuromuscular disease, arthrogryposis, or congenital anomalies of other organs or systems (n = 9); hips that underwent osteotomy within 1 year since closed reduction (n = 8); hips that underwent open reduction because of re-dislocation after closed reduction (n = 4); and hips with Type III or IV osteonecrosis according to Bucholz-Ogden's classification (n = 4). Ninety-one patients were eligible. We excluded 19% (17 of 91) of the patients, who were lost to follow-up before they were 8 years old, leaving 81% (74 of 91 patients) with full preoperative and most-recent data. Ninety-seven percent (72 patients) were girls and 3% (two patients) were boys. The mean ± standard deviation age was 14.0 months ± 6.4 months (range 3-40 months) at the time of closed reduction and 12.1 years ± 2.3 years (range 8.0-16.0 years) at the time of the latest follow-up examination, the duration of which averaged 11 years ± 2.2 years (range 6.5-15.4 years). To investigate whether longitudinal change in the acetabular edge's shape differed among hips with DDH, contralateral hips, and control hips, we identified control participants after searching our hospital's database for patients with a diagnosis of congenital idiopathic hemihypertrophy from October 2000 to November 2006 who had AP hip radiographs taken at 3 years old and then at older than 8 years. From 29 patients who met these criteria, we randomly excluded two male patients to match for sex because girls were predominant in the DDH group. We excluded another female patient from the control group because of a hip radiograph that revealed unacceptable rotation. Eventually, 26 patients were assigned to the control group. Control patients consisted of 24 girls (92%) and two boys (8%). The demographic characteristics of control patients was not different from those of 67 patients with unilateral DDH, except for laterality (left-side involvement: 64% [43 of 67] in the DDH group versus 38% [10 of 26] in the control group; odds ratio 1.7 [95% confidence interval, 1.0-2.8]; p = 0.035). The acetabular index and center-edge angle at 3 years old were measured using the lateral osseous margin of the acetabular roof (AIB and CEAB) and the lateral end of the acetabular sourcil (AIS and CEAS). The treatment outcome was classified as satisfactory (Severin Grade I or II) or unsatisfactory (Grade III or IV). The intraclass correlation coefficient (ICC) was used to compare the intraobserver and interobserver reliability of each method. We compared the predictability of residual hip dysplasia of each method at 3 years old as a proxy using the area under the receiver operating characteristic (AUC) curve. To evaluate longitudinal change in the acetabular edge's shape, we compared the proportion of hips showing coincidence of the two landmarks between 3 years old and the latest follow-up examination. To investigate whether the longitudinal change in the acetabular edge's shape differs among hips with DDH, contralateral hips, and control hips, we compared the proportion of coincidence among the three groups at both timepoints.
Intraobserver and interobserver reliabilities were higher for the CEAB (ICC 0.96; 95% CI, 0.94-0.98 and ICC 0.88; 95% CI, 0.81-0.92, respectively) than for the CEAS (ICC 0.81; 95% CI, 0.70-0.88 and ICC 0.69; 95% CI, 0.55-0.79, respectively). The AIB (AUC 0.88; 95% CI, 0.80-0.96) and CEAB (AUC 0.841; 95% CI, 0.748-0.933) predicted residual hip dysplasia better than the AIS (AUC 0.776; 95% CI, 0.67-0.88) and CEAS (AUC 0.72; 95% CI, 0.59-0.84) (p = 0.03 and p = 0.01, respectively). The proportion of hips showing coincidence of the two landmarks increased from 3 years old to the latest follow-up examination in hips with DDH (37% [25 of 67] to 81% [54 of 67]; OR = 8.8 [95% CI, 3.1-33.9]; p < 0.001), contralateral hips (42% [28 of 67] to 85% [57 of 67]; OR = 16.5 [95% CI, 4.2-141.9]; p < 0.001), and control hips (38% [10 of 26] to 88% [23 of 26]; OR = 14 [95% CI, 2.1-592.0]; p = 0.001). The proportion of coincidence in hips with DDH was not different from that in the contralateral hips and control hips at both timepoints.
Measuring the acetabular index and center-edge angle at 3 years old using the lateral osseous margin of the acetabular roof has higher reliability for predicting residual hip dysplasia than that using the lateral end of the acetabular sourcil in patients with DDH treated with closed reduction. Measuring the acetabular index and center-edge angle at an early age using the lateral end of the sourcil may lead to overdiagnosis of residual hip dysplasia and unnecessary treatment.
Level III, diagnostic study.
髋臼指数和中心边缘角是广泛应用的影像学参数。然而，测量这些参数的确切标志点尚未明确界定。虽然当髋臼顶的外侧骨缘与髋臼眉弓的外侧端重合时，它们的测量很简单，但当这两个标志点不一致时，对于应使用哪个标志点的建议存在分歧。使用具有高可靠性的影像学参数来预测残留髋关节发育不良有助于避免不必要的治疗。
问题/目的：我们旨在（1）比较用于测量髋臼指数和中心边缘角的两个标志点（髋臼顶的外侧骨缘和髋臼眉弓的外侧端）在观察者内和观察者间的可靠性，以及对发育性髋关节发育不良（DDH）患者残留髋关节发育不良的预测能力；（2）评估全身麻醉下闭合复位后髋臼边缘形状的纵向变化。
1985年2月至2006年7月，我们对116例DDH患者进行了全身麻醉下的闭合复位及石膏固定。纳入本研究的患者必须为脱位型DDH。我们排除了合并神经肌肉疾病、关节挛缩或其他器官或系统先天性异常的髋关节脱位患者（n = 9）；闭合复位后1年内接受截骨术的髋关节（n = 8）；因闭合复位后再脱位而接受切开复位的髋关节（n = 4）；以及根据Bucholz - Ogden分类为III型或IV型骨坏死的髋关节（n = 4）。91例患者符合条件。我们排除了19%（91例中的17例）在8岁前失访的患者，最终81%（91例中的74例）患者有完整的术前和最新数据。97%（72例）为女孩，3%（2例）为男孩。闭合复位时的平均年龄±标准差为14.0个月±6.4个月（范围3 - 40个月），最新随访检查时为12.1岁±2.3岁（范围8.0 - 16.0岁），随访时间平均为11年±2.2年（范围6.5 - 15.4年）。为了研究DDH髋关节、对侧髋关节和对照髋关节之间髋臼边缘形状的纵向变化是否不同，我们在医院数据库中搜索了2000年10月至2006年11月诊断为先天性特发性半侧肥大且在3岁和8岁以上时拍摄了前后位髋关节X线片的患者，确定了对照参与者。从符合这些标准的29例患者中，我们随机排除了2例男性患者以匹配性别，因为DDH组中女孩占主导。由于一张髋关节X线片显示旋转不可接受，我们从对照组中又排除了1例女性患者。最终，26例患者被分配到对照组。对照组患者包括24例女孩（92%）和2例男孩（8%）。对照组患者的人口统计学特征与67例单侧DDH患者的特征相似，除了侧别（左侧受累：DDH组为64%[67例中的43例]，对照组为38%[26例中的10例]；优势比1.7[95%置信区间，1.0 - 2.8]；p = 0.035）。在3岁时，使用髋臼顶的外侧骨缘（AIB和CEAB）和髋臼眉弓的外侧端（AIS和CEAS）测量髋臼指数和中心边缘角。治疗结果分为满意（Severin I级或II级）或不满意（III级或IV级）。组内相关系数（ICC）用于比较每种方法的观察者内和观察者间可靠性。我们使用受试者操作特征（AUC）曲线下面积作为代理，比较了每种方法在3岁时对残留髋关节发育不良的预测能力。为了评估髋臼边缘形状的纵向变化，我们比较了3岁至最新随访检查期间两个标志点重合的髋关节比例。为了研究DDH髋关节、对侧髋关节和对照髋关节之间髋臼边缘形状的纵向变化是否不同，我们比较了三个组在两个时间点的重合比例。
CEAB的观察者内和观察者间可靠性（ICC分别为0.96；95%CI，0.94 - 0.98和ICC 0.88；95%CI，0.81 - 0.92）高于CEAS（ICC分别为 0.81；95%CI，0.70 - 0.88和ICC 0.69；95%CI，0.55 - 0.79）。AIB（AUC 0.88；95%CI，0.80 - 0.96）和CEAB（AUC 0.841；95%CI，0.748 - 0.933）预测残留髋关节发育不良的能力优于AIS（AUC 0.776；95%CI，0.67 - 0.88）和CEAS（AUC 0.72；95%CI，0.59 - 0.84）（p分别为0.03和0.01）。在DDH髋关节（从37%[67例中的25例]增至81%[67例中的54例]；OR = 8.8[95%CI，3.1 - 33.9]；p < 0.001）、对侧髋关节（从42%[67例中的28例]增至85%[67例中的57例]；OR = 16.5[95%CI，4.2 - 141.9]；p < 0.001）和对照髋关节（从38%[26例中的10例]增至88%[26例中的23例]；OR = 14[95%CI，2.1 - 592.0]；p = 0.001）中，两个标志点重合的髋关节比例从3岁到最新随访检查均增加。在两个时间点，DDH髋关节的重合比例与对侧髋关节和对照髋关节的重合比例无差异。
对于接受闭合复位治疗的DDH患者，3岁时使用髋臼顶的外侧骨缘测量髋臼指数和中心边缘角预测残留髋关节发育不良的可靠性高于使用髋臼眉弓的外侧端。早期使用眉弓外侧端测量髋臼指数和中心边缘角可能导致残留髋关节发育不良的过度诊断和不必要的治疗。
III级，诊断性研究。
