Morris William Z, Napora Joshua K, Conry Keegan T, Liu Raymond W
Division of Pediatric Orthopaedics, Department of Orthopaedics, Rainbow Babies and Children's Hospitals at Case Western Reserve University, Cleveland, OH.
J Pediatr Orthop. 2019 Mar;39(3):119-124. doi: 10.1097/BPO.0000000000000881.
Factors including obesity and morphologic parameters around the hip that increase physeal stress are associated with an increased risk of slipped capital femoral epiphysis (SCFE). Recent evidence suggests that superior epiphyseal extension may confer stability to the physis and help protect against SCFE. The purpose of this study is to investigate the relationship between epiphyseal extension and SCFE using an age-matched and sex-matched cohort study.
We generated 2 separate cohorts for comparison: 89 patients with unilateral SCFE and 89 healthy subjects with no evidence of hip disease or deformity. We utilized the anterior-posterior and lateral films of the hip to measure the Southwick angle and the epiphyseal extension ratio (EER), defined as the ratio of extension of the capital femoral epiphysis down the femoral neck relative to the diameter of the femoral head. We then compared these measurements between cohorts and in subgroup analysis based on slip stability and whether subjects progressed to a contralateral slip.
The SCFE cohort demonstrated a decreased superior epiphyseal extension ratio compared with control (superior EER 0.71 vs. 0.68, P=0.002). There was also a significant downward trend in superior EER from the control subjects (0.71±0.07) to the stable slips (0.69±0.06) to the unstable slips (0.65±0.04) with an overall difference between the groups (P=0.001). Eighteen of 44 (41%) subjects with unilateral stable slips and at least 6 months of follow-up went on to develop SCFE of the contralateral limb. The subjects who developed contralateral slips were younger (11.6±1.2 vs. 12.7±1.4 y, P=0.008); however, there was no difference in superior or anterior epiphyseal extension (P=0.75 and 0.23, respectively). There was no significant linear correlation between Southwick angle and superior or anterior EER (r=0.13 and 0.17, respectively, P>0.05 for both).
Increasing capital femoral epiphyseal extension may confer physeal stability in the setting of SCFE. We propose that this epiphyseal extension reflects an adaptive response to limit physeal stress and reduce the risk for progression to SCFE.
Level III-prognostic study.
包括肥胖和髋关节周围形态学参数在内的增加骨骺应力的因素与股骨头骨骺滑脱（SCFE）风险增加相关。最近的证据表明，骨骺上延可能赋予骨骺稳定性并有助于预防SCFE。本研究的目的是使用年龄和性别匹配的队列研究来调查骨骺上延与SCFE之间的关系。
我们生成了2个独立的队列进行比较：89例单侧SCFE患者和89例无髋关节疾病或畸形证据的健康受试者。我们利用髋关节前后位和侧位X线片测量Southwick角和骨骺上延率（EER），EER定义为股骨头骨骺沿股骨颈向下的延伸长度与股骨头直径的比值。然后我们比较了队列之间以及基于滑脱稳定性和受试者是否进展为对侧滑脱的亚组分析中的这些测量值。
与对照组相比，SCFE队列的骨骺上延率降低（上EER 0.71对0.68，P = 0.002）。从对照组受试者（0.71±0.07）到稳定滑脱组（0.69±0.06）再到不稳定滑脱组（0.65±0.04），上EER也有显著的下降趋势，各组之间总体差异显著（P = 0.001）。44例单侧稳定滑脱且至少随访6个月的受试者中有18例（41%）继续发展为对侧肢体的SCFE。发生对侧滑脱的受试者更年轻（11.6±1.2岁对12.7±1.4岁，P = 0.008）；然而，骨骺上延或前延没有差异（分别为P = 0.75和0.23）。Southwick角与骨骺上延或前延之间无显著线性相关性（r分别为0.13和0.17，两者P>0.05）。
在SCFE情况下，增加股骨头骨骺上延可能赋予骨骺稳定性。我们提出这种骨骺上延反映了一种适应性反应，以限制骨骺应力并降低进展为SCFE的风险。
III级-预后研究。
