ObjectiveTo explore the effectiveness of minimally invasive osteotomy Ilizarov technique combined with intramedullary nail for femoral lengthening.MethodsSeventy-one patients with femoral shortening deformity who met the selection criteria between January 2013 and June 2016 were randomly divided into trial group (36 cases were treated with minimally invasive osteotomy Ilizarov technique combined with intramedullary nail for femoral lengthening) and control group (35 cases were treated with simple Ilizarov technique for femoral lengthening). There was no significant difference in age, gender, causes of femoral shortening, length of femoral shortening, rate of femoral deformity between the two groups (P>0.05). The operation duration, intraoperative blood loss, lengthening rate, external fixation duration, frequency of pin tract infection, osteotomy healing time, and range of motion (ROM) of knee at 1 year after operation were recorded and compared between the two groups.ResultsThe patients of two groups were followed up 12-60 months (mean, 31 months). Pin tract infection occured in 8 cases (10 pins), including 1 case (1 pin) in the trial group and 7 cases (9 pins) in the control group. There was significant difference in the incidence of pin tract infection between the two groups (χ2=5.265, P=0.022). All patients were cured by replacing the fixation pins, changing dressing actively, application of antibiotics, and adequate postoperative care. The operation duration, intraoperative blood loss, external fixation duration, osteotomy healing time, and ROM of knee at 1 year after operation of the trial group were superior to those of the control group, showing significant differences (P<0.05). There was no significant difference in the lengthening rate between the two groups (t=–1.581, P=0.153).ConclusionThe minimally invasive osteotomy Ilizarov technique combined with intramedullary nail in femoral lengthening increases the operation time, but the external fixation duration and incidence of pin tract infection are significantly reduced and the function of knee is significantly improved.