股骨颈动力交叉钉系统治疗移位型股骨颈骨折术后股骨颈中重度短缩的发生及危险因素分析

Risk factors for moderate and severe femoral neck shortening in displaced femoral neck fractures following treatment by a femoral neck system

目的探索股骨颈动力交叉钉系统(FNS)治疗中青年移位型股骨颈骨折术后股骨颈短缩的发生情况及危险因素。方法回顾性分析2019年12月至2021年12月福州市第二医院骨科采用闭合复位FNS治疗并获得随访的135例移位型股骨颈骨折患者资料。男85例,女50例;年龄51(42,57)岁,体重指数为22.6(20.9,24.2)kg/m^(2);骨折按Garden分型:Ⅲ型29例,Ⅳ型106例。观察短缩的情况,记录患者的性别、年龄、侧别、体重指数、骨折类型、高能量损伤、受伤至手术时间、断端皮质粉碎、复位质量(Garden指数)、部分负重时间、完全负重时间、功能评分(Harris评分)进行单因素分析,通过logistics回归分析发生中重度短缩的危险因素。结果135例患者术后获17.2(15.0,20.2)个月随访,均有不同程度股骨颈短缩,发生率为100%(135/135)。FNS固定移位型股骨颈骨折短缩4.2(2.6,7.7)mm。患者的短缩距离在术后3个月内持续加重,6个月内基本达稳定状态,6个月后较少发生持续性短缩。根据短缩距离分为轻度短缩组(<5 mm,76例)和中重度短缩组(≥5 mm,59例)。末次随访时轻度短缩组患者的髋关节Harris评分(91.7±2.3)分显著高于中重度短缩组(87.9±3.8)分,差异有统计学意义(P<0.001)。轻度短缩组患者的骨折愈合率98.7%(75/76)与中重度短缩组98.3%(58/59)比较,差异无统计学意义(P=1.000)。Logistic回归分析发现发生中重度短缩主要危险因素为骨折类型(GardenⅣ型)(OR=10.227,95%CI:1.845~56.693,P=0.008)、断端皮质粉碎(有)(OR=52.697,95%CI:9.870~281.352,P<0.001)、部分负重时间(<4周)(OR=0.168,95%CI:0.032~0.893,P=0.036)。结论FNS内固定治疗中青年移位型股骨颈骨折术后可能有较高股骨颈短缩发生率和髋关节功能下降,其主要危险因素是骨折类型(GardenⅣ型)、断端皮质粉碎、部分负重时间(<4周)。

Objective To investigate the incidence of and risk factors for femoral neck shortening in young and middle-aged patients with displaced femoral neck fracture treated by a femoral neck system(FNS).Methods A retrospective study was conducted to analyze the clinical data of 135 patients with displaced femoral neck fracture who had been treated by closed reduction and FNS internal fixation at Department of Orthopaedics,The Second Hospital of Fuzhou from December 2019 to December 2021.There were 85 males and 50 females,with an age of 51(42,57)years and a body mass index of 22.6(20.9,24.2)kg/m^(2).According to the Garden classification,there were 29 cases of typeⅢand 106 cases of typeⅣ.Femoral neck shortening was observed.The patients'gender,age,side of shortening,body mass index,fracture type,high-energy injury,time from injury to surgery,cortical comminution at the fracture end,reduction quality(Garden index),partial weight bearing time,complete weight bearing time,and functional evaluation(Harris score)were recorded for a univariate analysis.Multivariate logistic regression was used to analyze the influencing factors for moderate to severe shortening.Results All the 135 patients were followed up for 17.2(15.0,20.2)months.Different degrees of femoral neck shortening happened in all patients,yielding an incidence of 100%(135/135).The femoral neck shortening was 4.2(2.6,7.7)mm in displaced femoral neck fractures fixated by FNS.The shortening continued to worsen within the first 3 months after operation,reaching a stable state in the first 6 months.Persistent shortening hardly occurred after 6 months.According to the shortening distance,the patients were divided into a mild shortening group(76 cases<5 mm)and a moderate to severe shortening group(59 cases≥5 mm).The Harris score at the last follow-up in the mild shortening group(91.7±2.3)was significantly higher than that in the moderate to severe shortening group(87.9±3.8)(P<0.001).The fracture healing rate was 98.7%(75/76)in the mild shortening group and 98.3%(58/59)in the moderate to severe shortening group,showing no significant difference(P=1.000).Logistic regression analysis found that the risk factors for moderate to severe shortening were fracture type(typeⅣ)(OR=10.227,95%CI:1.845 to 56.693,P=0.008),cortical comminution at the fracture end(if present)(OR=52.697,95%CI:9.870 to 281.352,P<0.001),and partial weight bearing time<4 weeks(OR=0.168,95%CI:0.032 to 0.893,P=0.036).Conclusions The incidence of femoral neck shortening may be high in young and middle-aged patients with displaced femoral neck fracture treated by FNS,leading to decreased hip function.The main risk factors for femoral neck shortening are fracture type(Garden typeⅣ),cortical comminution at the fracture end and partial weight-bearing time less than 4 weeks.