RESUMO
Objective:To analyze the therapeutic effect of medial gastrocnemius muscle flap transfer combined with induced membrane technique in repairing anterior medial Gustilo-Anderson type ⅢB injury of the middle and upper tibia accompanied by bone defect.Methods:A retrospective case series study was conducted to analyze 21 patients with anterior medial Gustilo-Anderson type ⅢB injury of middle and upper tibia accompanied by bone defectanterior medial tibial fractures admitted to Xijing Hospital，Air Force Military Medical University from April 2017 to January 2019. There were 15 males and 6 females，with the age of （38.6 ± 7.6）years （range，18-66 years）. After admission，all patients had bone defect repair and fixation and soft tissue defect repair using membrane induction technique in the first stage. The area of soft tissue defect ranged from 8.0 cm × 6.0 cm to 16.0 cm × 12.0 cm. The length of tibial defect was （5.5 ± 1.8） cm （ranged，3.5-11.0 cm）. The size of metastasis of medial gastrocnemius flap ranged from 12.0 cm × 8.0 cm to 22.0 cm × 13.0 cm. The survival rate of muscle flap was observed. One week after the wound was stabilized，skin grafting on the surface of muscle flap was performed at second stage. The graft survival was observed. The induced membrane technique was used to reconstruct bone defects at third stage. The infection index，lower extremity functional scale （LEFS） and Mazur ankle function score were compared before and at the last follow-up. The fracture healing and related complications were observed，and the lower limb function was evaluated by Johner-Wruhs scoring system at the last follow-up.Results:All patients were followed up for 11-26 months ［（18.4 ± 5.1） months］. The muscle flap transferred survived in all patients at first stage. The skin graft survived at second stage，and the wound healing time was 1-4 weeks ［（3.1 ± 0.5）weeks］. After the surgery at third stage，the healing time of bone fracture was （8.2 ± 0.7）months （range，6-10 months）. A significantly lowered level of infection was observed at the last follow-up compared to that before operation （ P < 0.01）. The LEFS and Mazur ankle function scores of the affected limb were （52.2 ±8.9）points and （75.2 ± 13.1）points at the last follow-up，significantly higher than those before operation ［（36.0 ± 5.6）points，（53.7 ± 14.6）points］ （ P < 0.01）. The soft tissue defect was repaired satisfactorily，and the broken ends of bone defects were healed at the last follow-up. Delayed bone union occurred in 3 patients，but no infection，osteomyelitis，foot drop or other complications occurred. According to Johner- Wruhs score，18 patients were rated as excellent，2 patients as good，1 patient as fair and 0 patient as poor，with the excellent and good rate of 95%. Conclusion:For patients with anterior medial Gustilo-Anderson type ⅢB injury of the middle and upper tibia accompanied by bone defect，transfer of medial gastrocnemius head muscle flap combined with induced membrane technique can effectively repair the injured limb，reduce infection and restore partial function of the lower limb，indicating that the procedure is an effective treatment strategy with satisfactory clinical results.
