胫骨中下1/3螺旋形骨折合并的后踝骨折块形态学分析

Morphological analysis of posterior malleolar fracture associated with distal 1/3 spiral tibial shaft fracture

目的利用CT对胫骨中下1/3骨折合并的后踝骨折块进行形态学分析,以帮助治疗方案的选择。方法选择120例胫骨中下1/3螺旋形骨折患者,对每位患者术前常规行踝关节CT检查,测量后踝骨折块占整个胫骨远端平台的面积比例S%、后踝骨折线与内外踝轴线所成的角度A、后踝骨折线两端点距离Lab及自后踝尖垂直于后踝骨折线的垂线段长度Lcd。对面积比S%与角度A、Lab、Lcd行多元线性回归。结果 Lab平均为26.8 mm,Lcd平均为13.6 mm,骨折线与内外踝轴线夹角A平均为21.1°,后踝骨折者块占整个断层面积百分比S%平均为20.3%。Lcd值及Lab值对面积比S%影响较大。结论胫骨中下1/3骨折合并的后踝骨折块形态各异,术前使用CT明确骨折块形态对手术方式及入路的选择至关重要。

Objective To analyse morphology of the posterior malleolar fracture associated with distal 1/3 spiral bitial shaft fracture so as to help select the treatment options.Methods A total of 120 distal 1/3 spiral tibial shaft fractures were studied.CT scan was routinely performed in the ankle region,whereas the distal third spiral tibial fracture was found in the primary plain X-ray films.We measured the following four indexes： ①S%： the ratio of the posterior fragment area to the total cross-sectional area of the tibial plafond;②angle A： the angle between the bimalleolar axis and the major fracture line of the posterior malleolus;③Lab： the distance of two endpoint of fracture line of the posterior malleolus;④Lcd： the length of vertical line from the tip of posterior malleolus perpendicular to fracture line.Multiple linear regression for S%,angle A,Lab,Lcd was assessed.Results The average length of Lab is 26.8 mm.The average length of Lcd is 13.6 mm.The average of angle A is 21.1° and the average S% is 20.3%.The value of Lcd and Lab influences S%.Conclusion The fracture lines of posterior malleolar fractures associated with distal third tibial fracture appear to be highly variable.Preoperative morphological analysis of the posterior malleolar fractures by CT is very important to select the treatment options.