Objective To compare effects, advantages and disadvantages of simple internal fixation to that of l imited internal fixation with external supporting frame fixation in the treatment of complex fractures of tibial plateau. Methods From July 2002 to August 2006, 66 cases of complex fractures of the tibial plateau were divided into the internal fixation group (n=39) and the external fixator group (n=27). The interal fixation group had 18 cases of IV, 7 cases V and 14 cases VI according to Schatzker, including 25 males and 14 females aged 18-79 years with an average of 45.4 years. The external fixator group had 13 cases of IV, 6 cases V and 8 cases VI according to Schatzker, including 18 males and 9 femles aged 18-64 years with an average of 44.2 years. No significant difference was evident between the two groups (P gt; 0.05). Patients were treated by using screws, steel plates or external supporting frame fixation strictly based on the princi ple of internalfixation. Results All patients were followed up for 1-5 years. Fracture healed with no occurrence of nonunion. Two cases inthe internal fixation group presented partial skin infection and necrosis, and were cured through the dressing change and flap displacement. Fracture heal ing time was 6-14 months with an average of 7.3 months. The time of internal fixator removal was 6-15 months with an average of 8.3 months. In the external fixation group, 11 cases had nail treated fluid 7 days to 3 months after operation, combining with red local skin; 3 cases had skin necrosis; and 3 cases had loose bolts during follow-up. Through debridement, dressing change and flap displacement, the skin wounds healed. Fracture heal ing time was 3-11 months with an average of 5.1 months. The time of external fixator removal was 5-11 months with an average of 6.4 months. At 8-14 months after operation, the knee function was assessed according to Merchant criteria. In the internal fixation group, 29 cases were excellent, 4 good, 5 fair and 1 poor, while in the external fixation group, 20 cases were excellent, 3 good, 2 fair and 2 poor. There was no significant difference between the two groups (P gt; 0.05). Conclusion The therapeutic effects of simple internal fixation and l imited internal fixation with external supporting frame fixation were similar in the treatment of complex fractures of tibial plateau. Fixation materials should be selected according to the state of injury and bone conditions for the treatment of tibial plateau fracture of type IV, V and VI based on Sehatzker classification.