Objective To explore the technique and clinicaleffects of internal fixation of complicated distal femoral fractures using the supporting steel of AO femoral condyles.Methods From October 2001 to February 2004, 23 cases of complicated distal femoral fractures were treated with open reduction and internal fixation using the supporting steel of AO femoral condyles. Of 23 cases, there were 19 males and 4 females, aged 27-55 years. The locations were the right side in 10 cases and the left side in 13 cases. Fracture caused by traffic accident in 16 and by fall in 7, including 14 closed fracture and 9 open fracture, 21 fresh fracture and 2 old fracture. Accordingto AO classification, 6 cases were classified as type A extra-articular fracture and 17 cases as type C intra-articular fracture. The X-ay films before operation showed comminuted fracture of femoral intercondyles and femoral supracondyles. All cases received scientific and rational rehabilitative treatment postoperatively. Results The postoperative follow-up ranged from 6months to 20 months, 23 cases achieved fracture healing with an average healing period of 10.3 months (from 7 months to 16 months). According to the criteria of Kolmert and Wulff, the results were excellent in 16 cases, good in 4 cases, fair in 2 case andpoor in 1 case. The excellenct and good rate was 86.9%.Conclusion Internal fixation with the supporting steel of AO femoral condyles for treatment of complicated distal femoral fractures has advantages of reasonable design, convenient operation, firm fixation and reliable clinical outcome .