负重X线侧位片在踝关节骨折畸形愈合复位评估中的价值

Effectiveness of weight-bearing lateral radiographs in evaluation of ankle malunited fractures restoration

目的探讨踝关节负重x线侧位片在踝关节骨折畸形愈合复位评估中的意义。方法回顾性分析2010年3月至2012年10月踝关节骨折畸形愈合接受重建手术治疗的17例患者资料，男9例，女8例；年龄17～64岁，平均40．2岁。Takakura踝关节炎退变分级：1级7例，2级4例，3级6例。接受单纯切开复位内固定术5例，踝上胫骨截骨术5例，踝上腓骨截骨延长术2例，踝上胫腓骨截骨术5例。比较患者手术前、后负重x线正位片胫腓间隙，踝穴位X线片内踝间隙、胫腓间隙和胫腓重叠距离，x线侧位片胫骨侧面角、胫骨轴线与距骨顶关节面中心的位移差（x值）和胫距关节面圆心位移差（d值）。应用美国足踝外科协会（American Orthopaedic Foot and Ankle Society，AOFAS）踝与后足评分对患者手术前、后踝关节功能进行评估。结果17例患者均获9～32个月随访，骨折均愈合，愈合时间11～14周；未见踝关节退变等级加重。手术前、后负重x线正位片上胫腓间隙、踝穴位X线片上内踝间隙、胫腓间隙和胫腓重叠距离比较无差异；胫骨侧面角[术前（76．9。±4．1。）与术后（80．9。±5．2。）]、Ⅳ值[术前（10．8±2．1）mm与术后（2．0±0．5）mm]、d值[术前（4．5±1．5）Inn与术后（2．2±1．0）mm]比较均有差异。术前AOFAS踝与后足评分为（45．7±15．9）分，末次随访时为（82．0±9．9）分。结论负重x线侧位片可以辅助判断踝关节复位情况，即使负重正位及踝穴位x线片示测量数据均在正常范围内，x线侧位片示相关指标仍可出现明显畸形；X线侧位片示踝关节解剖复位的标准是胫骨轴线通过距骨顶关节面中心、胫距关节面平行。

Objective To evaluate the significance of weight-bearing lateral radiographs in evaluation of malunited frac-tures of the ankle. Methods 17 patients with malunited fractures of the ankle were treated by different reconstructive operations be-tween March 2010 and October 2012, including 9 females and 8 males, aged from 17 to 64 years. According to the Takakura classifi- cation of ankle arthritis, there were 7 patients in grade 1, 4 in grade 2 and 6 in grade 3. Simple open reduction and internal fixation were performed in 5 patients, supramalleolar tibial osteotomy in 5, lengthening osteotomy of the fibula in 2, supramalleolar tibial and fibular osteotomy in 5. Tibiofibular clear space on the anteroposterior radiograph. Medial clear space, tibiofibular clear space and tib-iofibular overlap on ankle mortise radiographs were compared preoperatively and at last follow-up. Tibial lateral surface angle （TLS）, the offset of the center of talar rotation from the tibial axis, and the displacement of tibiotalar articular surface center on weight-bear-ing lateral X-ray were also compared preoperatively and at last follow-up. AOFAS score was used to evaluate the function of the ankle. Results The duration of follow-up was 9 to 32 months. Bone healing was observed in all patients, and the average healing time was 11 to 14 weeks. Ankle joint degeneration grade had no exacerbation. The medial clear space, tibiofibular clear space and tibiofibular overlap had no significant difference between the pre and postoperative. Statistically significant change was seen postoperatively in the values of TLS （76.9°±4.1° vs 80.9°±5.2°）. The offset of the center of rotation from the tibial axis and the displacement of tibiotalar articular surface center were changed from 10.8＋2.1 mm to 2.0_＋0.5 mm and 4.5±1.5 mm to 2.2±1.0 ram, respectively. The average AOFAS score was improved from 45.7±15.9 points preoperatively to 82.0±9.9 points postoperatively. Conclusion Weight-bearing lateral radiographs can be used to judge the ankle restoration. Even if the mortise radiograph had relative good realignment, it may ap-pear obvious deformity on lateral radiographs. Good reduction of lateral radiographs requires that the mid axis of the tibia should pass through the center of talar rotation and tibiotalar articular surface be parallel on the lateral radiograph.