Objective To investigate the application of operation plan based on injury stress sequence in the treatment of degree Ⅲ and Ⅳ ankle fractures with Lange-Hansen classification of pronation and external rotation.Methods From May 2019 to May 2022,80 eligible patients of degree Ⅲand Ⅳ ankle fractures with Lange-Hansen classification were selected prospectively and randomely divided into 2 groups:40 patients in the study group were treated with surgical reduction according to the sequence of injury stress,and the other 40 patients in the control group were treated with traditional reduction sequence.The operative time,intraoperative blood loss,fracture healing time,full weight-bearing time,Ankle dorsoextension Angle,plantar flexion Angle,and American Orthopaedic Foot and Ankle Association were compared between the two groups Society,AOFAS)Ankle and posterior foot function scores and complications.Results The surgical time[(44.80±5.12)min vs.(47.61±6.42)min]and surgical bleeding volume[(43.81±9.02)ml vs.(51.50±12.01)ml]between the study group and the control group were statistically significant(all P＜0.05).Before surgery,there had no significant differences in ankle joint dorsiflexion angle,plantar flexion angle,AOFAS ankle and hind foot function score in 2 groups(all P＞0.05).The ankle dorsiflexion angle at 3 months after surgery[(16.84±1.77)° vs.(15.50±1.65)°],plantar flexion angle at 3 months after surgery[(45.64±4.10)° vs.(42.58±3.86)°]and at 6 months after surgery[(52.38±3.03)°vs.(50.64±3.74)°],the maximum walking distance score[(3.50±0.64)vs.(3.16±0.60)],ground walking score[(2.06±0.56)vs.(1.72±0.48)]and ankle joint anteroposterior activity score at 3 months after surgery[(4.96±1.38)vs.(4.16±1.07)]of the study group were all higher than those in the control group(all P＜0.05).There was no statistically significant difference in terms of fracture healing time,complete weight-bearing time,postoperative pain score,ankle joint function autonomous activity support score,abnormal gait score,maximum walking distance score at 6 months after surgery,ground walking score,ankle joint anterior and posterior activity score and surgical complications between 2 group(all P＞0.05).Conclusion According to the sequence of injury stress,surgical reduction for the treatment of grade Ⅲ and Ⅳ ankle fractures of Lange-Hansen classification of middle pronation and external rotation can shorten the operation time and promote the early recovery of joint function.

Objective To investigate the application of operation plan based on injury stress sequence in the treatment of degree Ⅲ and Ⅳ ankle fractures with Lange-Hansen classification of pronation and external rotation.Methods From May 2019 to May 2022,80 eligible patients of degree Ⅲand Ⅳ ankle fractures with Lange-Hansen classification were selected prospectively and randomely divided into 2 groups:40 patients in the study group were treated with surgical reduction according to the sequence of injury stress,and the other 40 patients in the control group were treated with traditional reduction sequence.The operative time,intraoperative blood loss,fracture healing time,full weight-bearing time,Ankle dorsoextension Angle,plantar flexion Angle,and American Orthopaedic Foot and Ankle Association were compared between the two groups Society,AOFAS)Ankle and posterior foot function scores and complications.Results The surgical time[(44.80±5.12)min vs.(47.61±6.42)min]and surgical bleeding volume[(43.81±9.02)ml vs.(51.50±12.01)ml]between the study group and the control group were statistically significant(all P＜0.05).Before surgery,there had no significant differences in ankle joint dorsiflexion angle,plantar flexion angle,AOFAS ankle and hind foot function score in 2 groups(all P＞0.05).The ankle dorsiflexion angle at 3 months after surgery[(16.84±1.77)° vs.(15.50±1.65)°],plantar flexion angle at 3 months after surgery[(45.64±4.10)° vs.(42.58±3.86)°]and at 6 months after surgery[(52.38±3.03)°vs.(50.64±3.74)°],the maximum walking distance score[(3.50±0.64)vs.(3.16±0.60)],ground walking score[(2.06±0.56)vs.(1.72±0.48)]and ankle joint anteroposterior activity score at 3 months after surgery[(4.96±1.38)vs.(4.16±1.07)]of the study group were all higher than those in the control group(all P＜0.05).There was no statistically significant difference in terms of fracture healing time,complete weight-bearing time,postoperative pain score,ankle joint function autonomous activity support score,abnormal gait score,maximum walking distance score at 6 months after surgery,ground walking score,ankle joint anterior and posterior activity score and surgical complications between 2 group(all P＞0.05).Conclusion According to the sequence of injury stress,surgical reduction for the treatment of grade Ⅲ and Ⅳ ankle fractures of Lange-Hansen classification of middle pronation and external rotation can shorten the operation time and promote the early recovery of joint function.

Objective: To investigate changes in the three⁃dimensional position of the maxillary canine during the distal movement of the maxillary first molar by a mini⁃implant combined with a CD appliance. Methods: Ten typodont models of class II malocclusion were selected, and one side was randomly chosen as the experimental group. The CD ap⁃ pliance was bonded to the maxillary canine and first molar of the experimental group, and 1.2 mm stainless steel wire was bent as the anchorage, which was fixed on the model to simulate mini⁃implants implanted in the zygomatic alveolar ridge. Then, 180 g orthodontic force was applied to the canine of the experimental group; the other side was recognized as the control group and was not used for strengthening. Six mini⁃implants were implanted in different parts of the mod⁃ el and used as a reference before and after the experiment. The models were placed in an incubator and heated at 56 ℃ in a water bath for 2 min. The models were scanned before and after thermostatic water bath treatment with a 3⁃shape scanner. Then, the digital models were overlapped through the reference points, and the positions of the canines and first molars were measured before and after the experiment. Results: The sagittal movement distance of the first molar in the experimental group was ( 0.25 ± 0.33) mm, and the vertical movement distance was (0.25 ± 0.28 )mm, which was significantly different from the control group (P < 0.05), while the transverse change was not significantly different (P > 0.05). There was no significant difference in the root position of the first molar in the experimental group (P > 0.05). The lateral and vertical displacement distances of the maxillary canine crown in the experimental group were (4.03 ± 2.11) mm and (1.86 ± 1.01) mm, respectively, which were significantly different from those in the control group (P < 0.001), while the sagittal changes showed no significant differences (P > 0.05). In the experimental group, there was no significant difference in the position of the apex of the maxillary cusp (P > 0.05). Conclusion Our in vitro study showed that the maxillary canines inclined buccally accompanied by a small amount of intrusion during molar distaliza⁃ tion by a mini⁃implant combined with a CD appliance.