Objeetive To investigate the clinical efficacy of inverted intmmedullary nail combined with medial minimally invasive plate in treatment of type C2 and C3 distal femoral fractures.Methods A retrospective case control study was conducted on 38 patients with complex distal fractures of the femur treated from January 2015 to January 2017.There were 22 males and 16 females,aged 24-72 years [(45.6 ± 2.5)years].AO fracture classification was type C2 in 24 patients and type C3 in 14.All of them were fresh closed fractures.The time duration from injury to operation was 4-16 days (average,7.5 days).Based on the different surgical methods,the patients were divided into lateral single plate fixation group (single plate group,20 patients) and inverted intramedullary nail combined with medial minimally invasive locked plate fixation group (locked plate group,18 patients).The two groups were compared in terms of operation condition,early weight bearing time,fracture healing time,postoperative complications,postoperative knee function and activity of living.Hospital for Special Surgery (HSS) score was used for evaluating postoperative knee function and Barthel index for activity of living.Results The patients were followed up for 10-24 months [(12.2 ± 1.8) months].The operation duration was (110.5 ± 35.4) min for single plate group and (116.7 ± 42.3) min min for locked plate group(P ＞0.05).Intraoperative blood loss in single plate group was [(450.5 ± 120.7)ml] and [(455.2 ± 130.4) ml] in locked plate group (P ＞ 0.05).The early weight bearing time in single plate group was (28.5 ± 8.6)days and 18.7 ± 4.9 (P ＜ 0.01)days in the locked plate group.The fracture healing time in single plate group was (8.5 ± 2.2) months,and [(6.5 ± 1.6) months] in locked plate group (P ＜ 0.01).After 3 weeks,6 months and 12 months,HSS scores of knee joint function of the locked plate group was significantly better than that of single plate group (P ＜ 0.01).At 6 months and 12 months after operation,Barthel index score of locked plate group was significantly better than that of single plate group (P ＜ 0.01).No infection occurred in two groups after operation.There were no complications such as internal fixation failure,knee valgus,external rotation deformity or fat embolism in locked plate group.There were two cases of internal fixation failure,one knee eversion,and two knee varus in single plate group (P ＜ 0.01).Conclusion Compared with single plate fixation,the therapeutic method of inverted intramedullary nail combined with medial minimally invasive locked plate has the advantages of early weight bearing time,quick recovery,better function restoration and fewer complications,and hence is a preferable choice for treatment of type C2 and C3 complex distal femoral fractures.