Fibular Osteotomy And Distal Tibiofibular Syndesmosis Fusion For Treatment Of Chronic Valgus Pilon Fracture Malunion

Objective Clinically,the cases of chronic Pilon fracture malunion were relatively rare.The reports of related operations were few,so the clinical treatment was difficult.However,the operative techniques for ankle fracture malunion were relatively mature.The cases of ankle valgus deformity(fibula valgus and shortening)can be corrected by lateral malleolus osteotomy,which was more conductive to the further surgical correction of the distal tibia deformity.The operation method was worthy of clinical reference.However,Pilon fracture malunion may have the characteristics of articular surface collapse and bone defect in the distal tibia.Conventional surgical approaches were difficult to achieve.Therefore,in view of the characteristics of chronic valgus Pilon fracture malunion,this study adopted fibula osteotomy combined with distal tibiofibular syndesmosis fusion treatment strategy to explore the clinical efficacy of this operative method.Methods 8 patients with chronic valgus Pilon fracture malunion from January 2011 to January 2017 were treated in our department.There were 7 males and 1 female,at mean age of 34.6 years(range,20-47 years).The average interval between initial injury and final operation was 13.4 months(range,7-21 months).All deformities were evaluated individually based on pre-operatively weight-bearing X-ray and 3D CT scan,and 3D printing model was also used for preliminary surgery.Weight-bearing X-ray showed posterior subluxation of ankle joint in 5 cases.There were 5 cases of fibular fracture at primary injury,and 2 cases of fibular fracture malunion.Fibular osteotomy and distal tibiofibular syndesmosis fusion strategy was carried out to reduce articular surface congruency and regain lower limb alignment.The operation time,intraoperative blood loss,postoperative complications,bone healing time,fracture reduction,ankle motion and visual analogue score(VAS)was regularly recorded after operation.Clinical function was evaluated according to the American Orthopedic Foot and Ankle Society(AOFAS)Ankle-Hindfoot score and the MOS item short from health survey(SF-36)Results The average operative time of all cases in this group was 126.1±1 7.7 min(range,96-151 min),and the average intraoperative blood loss was 180.9±44.3 ml(range,130-240 ml).All cases were followed up for average 18.7 months(range,12-30 months).All the incisions were primarily healed.There were no infection,neurovascular injuries or implant failure.All patients achieved primary bone union,and the average bone healing time was 15.7 weeks(range,13-19 weeks)with good lower limb alignment.No internal fixation failure or reduction loss occurred during follow-up.At last follow-up,The PF,RP,BP,GH and SF in SF-36 were improved respectively from(28.75±12.64),(18.75×17.68),(37.50±18.90),(36.88±9.98),(51.25±18.08)points(range,0-85 points)to(60.00±11.02),(53.13±16.02),(68.75±17.68),(65.50±8.45),(73.75±10.26)points(range,33-100 points),and the differences were statistically significant(t=7.26,P<0.05;t=4.25,P<0.05;t=5.00,P<0.05;t=4.32,P<0.05;t-2.73,P<0.05).At last follow-up after surgery,AOFAS score was significantly improved from 31.3±7.4 points(range,25-40 points)preoperatively to 77.1±11.6 points(range,63-90 points)postoperatively.diference was statistically significant(t=8.977,P<0.05).At the last follow-up,the VAS score was 1.6±0.7 points(range,0-3 points),and the difference was statistically significant(t=4.410,P<0.01)compared with the preoperative score 4.1±1.3 points(range,2-7 points).The range of ankle flexion and extension was also improved.The average dorsal extension was 28.3°±6.7°,the average plantar flexion was 30.1°±8.9°.There was no significant difference compared with the preoperative dorsal extension(26.6°±7.2°)and the plantar flexion(28.5°±4.3°)(t-1.112.P>0.05;t=0.975,P>0.05).7 patients returned to work at about 9.7 months(range,6-14 months)after surgeryConclusions For chronic valgus Pilon fractures malunion,fibular osteotomy and distal tibiofibular syndesmosis fusion can effectively restore articular congruency and lower leg alignment,alleviate ankle pain,delay arthritis progression and get satisfactory short term clinical effect with fewer complications.