Zhao Hongmou, Liang Xiaojun, Yu Guangrong, Li Yi, Lu Jun, Zhang Dongsheng
Department of Foot and Ankle Surgery, Honghui Hospital Affiliated to the Medical College of Xi'an Jiaotong University, Xi'an Shaanxi 710054, PR China.
Department of Mechanics, Shanghai University, PR China.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2013 Oct;27(10):1190-5.
To investigate the effectiveness and biomechanical analysis of 3 fixation methods of screw anterior-posterior fixation (SAPF), screw posterior-anterior fixation (SPAF), and buttress plate fixation (BPF) in treatment of posterior Pilon fractures.
Fifteen fresh-frozen skeleto-ligamentous lower leg specimens were harvested to establish the models of posterior Pilon fracture, and then fracture was fixed with BPF (n = 5), SAPF (n = 5), and SPAF (n = 5). Vertical force was loaded to internal fixation failure in a speed of 1 cm/minute with servohydraulic testing machine. The instantaneous loads of 1 mm and 2 mm steps and the failure modes were recorded. Between May 2008 and December 2011, 56 patients with posterior Pilon fracture were treated with SAPF (SAPF group) in 11 cases, or SPAF (SPAF group) in 26 cases, or BPF (BPF group) in 19 cases. There was no significant difference in age, gender, injury cause, side, disease duration, and complications among groups (P > 0.05). Clinical and radiographic examinations were used to assess the reduction and healing of fracture; the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the visual analogue scale (VAS) were used to evaluate the functional outcomes.
No breaking or bending was observed in all specimens, fixation failure was caused by cancellous bone compression. The instantaneous loads of 1 mm and 2 mm steps were the largest in BPF group, larger in SPAF group, and smallest in SAPF group, showing significant differences among 3 groups (P < 0.05). A total of 47 cases were followed up 16-54 months (9 in SAPF group, 22 in SPAF group, and 16 in BPF group), with a mean time of 35.2 months. Fixation failure was found in 2 cases of SAPF group; the other cases obtain bony union within 3 to 4 months (mean, 3.2 months) with no fixation failure. The AOFAS score was significantly lower in SAPF group than in SPAF and BPF groups (P < 0.05), but no significant difference was found between SPAF and BPF groups (P > 0.05). The VAS score was significantly higher in SAPF group than in SPAF and BPF groups (P < 0.05), but no significant difference was found between SPAF and BPF groups (P > 0.05).
SAPF could not reach enough fixation strength for the posterior Pilon fracture; both SPAF and BPF could reach rigid fixation, and have good effectiveness. And from the biomechanical points, BPF could reach better fixation strength than screw fixations.
探讨螺钉前后固定（SAPF）、螺钉后前固定（SPAF）及支撑钢板固定（BPF）3种固定方法治疗后Pilon骨折的有效性及生物力学分析。
采集15例新鲜冷冻的小腿骨韧带标本建立后Pilon骨折模型，然后分别采用BPF（n = 5）、SAPF（n = 5）和SPAF（n = 5）进行骨折固定。用伺服液压试验机以1 cm/分钟的速度施加垂直力直至内固定失效。记录1 mm和2 mm位移时的瞬时载荷及失效模式。2008年5月至2011年12月，56例后Pilon骨折患者，其中11例采用SAPF治疗（SAPF组），26例采用SPAF治疗（SPAF组），19例采用BPF治疗（BPF组）。各组间年龄、性别、损伤原因、患侧、病程及并发症差异无统计学意义（P > 0.05）。采用临床及影像学检查评估骨折复位及愈合情况；采用美国矫形足踝协会（AOFAS）踝-后足评分及视觉模拟量表（VAS）评估功能结果。
所有标本均未出现断裂或弯曲，固定失效均由松质骨压缩所致。BPF组1 mm和2 mm位移时的瞬时载荷最大，SPAF组次之，SAPF组最小，3组间差异有统计学意义（P < 0.05）。共47例患者获得随访，随访时间16 - 54个月（SAPF组9例，SPAF组22例，BPF组16例），平均35.2个月。SAPF组有2例出现固定失效；其余患者均在3至4个月（平均3.2个月）内获得骨性愈合，无固定失效发生。SAPF组AOFAS评分显著低于SPAF组和BPF组（P < 0.05），但SPAF组和BPF组间差异无统计学意义（P > 0.05）。SAPF组VAS评分显著高于SPAF组和BPF组（P < 0.05），但SPAF组和BPF组间差异无统计学意义（P > 0.05）。
SAPF对后Pilon骨折无法达到足够的固定强度；SPAF和BPF均可达到坚强固定，且疗效良好。从生物力学角度来看，BPF比螺钉固定能达到更好地固定强度。
