Effectiveness of weight-bearing lateral radiographs in evaluation of ankle malunited fractures restoration / 中华骨科杂志

ABSTRACT

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 mm, 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.