闭合复位"成功"儿童孟氏骨折上尺桡关节的MRI表现

Magnetic resonance appearances of proximal radioulnar joint in pediatric Monteggia fracture after"successful"closed reduction

目的通过儿童孟氏骨折闭合整复"成功"后进行磁共振成像(magnetic resonance imaging,MRI)检查评估上尺桡关节及上尺桡关节重要稳定结构环状韧带的复位情况,以指导儿童孟氏骨折的临床治疗。方法回顾性分析2015年5月至2019年8月烟台市烟台山医院67例有完整MRI资料的闭合复位成功的孟氏骨折患儿的临床及影像学资料,其中男43例,女24例,年龄范围为3岁9个月至11岁,平均年龄6岁9个月。所有患儿均在闭合整复后2~3 d内进行MRI检查。通过对MRI图像进行分析、测量,观察上尺桡关节匹配情况及环状韧带复位情况,并测量上尺桡关节间隙最大距离。计数资料采用Fisher确切概率法,计量资料采用t检验。结果MRI检查结果显示67例闭合复位"成功"的患儿中,环状韧带仍环绕桡骨头的15例,患儿上尺桡关节均匹配良好;环状韧带不包绕桡骨头、移位、嵌入肱桡关节间隙的52例,其中21例上尺桡关节匹配良好,31例上尺桡关节匹配不良,差异具有统计学意义(P<0.001)。15例环状韧带环绕桡骨头患儿上尺桡关节最大间隙为(1.2±0.3)mm。52例环状韧带不环绕桡骨头患儿上尺桡关节最大间隙为(2.4±1.3)mm,比较差异具有统计学意义(t=-6.04,P<0.001)。肘关节功能按照Mackay功能评定标准,优67例,优良率达100%,仅3例患儿前臂旋转过程中肘关节有轻微挫动感。X线片随访观察,患儿肱桡关节均对应良好,无桡骨头半脱位、再脱位。尺骨骨折端均满意愈合,无内固定物松动、断裂、脱出等。结论儿童孟氏骨折肱桡关节放射学复位不一定为解剖学复位,应同时考虑上尺桡关节和环状韧带的复位情况。MRI检查能精确评估上尺桡关节和环状韧带复位情况。

Objective To explore the magnetic resonance imaging(MRI)appearances of proximal radioulnar joint and annular ligament in children with pediatric Monteggia fracture after"successful"closed reduction.Methods MRI were retrospectively reviewed for 67 children with Monteggia fractures under"successful"closed reduction from May 2015 to August 2019.There were 43 boys and 24 girls with an age range of(45-132)months.MRI were acquired less than(2-3)days after closed reduction.The congruency of proximal radioulnar joint and the reduction of annular ligament were qualitatively recorded and maximal space of proximal radioulnar joint was quantitatively measured.Fisher's exact test was utilized for comparing categorical variables.For statistical analysis,Student t-test was employed.Results Annular ligament was reduced in 15 cases and all of them had excellent congruency of proximal radioulnar joint.Annular ligament was displaced in 52 children.The congruency of proximal radioulnar joint was excellent(n=21)and poor(n=31)(P<0.001).In 15 children with repositioned annular ligaments,maximal space of proximal radioulnar joint was(1.2±0.3)mm;in 52 children with displaced annular ligaments,maximal space of proximal radioulnar joint was(2.4±1.3)mm(t=-6.04,P<0.001).According to the Mackay's scoring system,all clinical outcomes were excellent(100%)and only 3 cases had snapping during forearm rotation.Follow-up radiographs indicated that all ulnar fractures healed and there were no instance of nonunion,re-dislocation,subluxation or loosening implant.Conclusions Radiological reduction of humeroradial joint is not necessarily anatomical reduction.Congruency of proximal radioulnar joint and reposition of annular ligament should also be considered.MR is capable of precisely assessing proximal radioulnar joint and annular ligament.