Background With a type C3 distal radius fracture it is extremely difficult to maintain the reduction and to restore congruity of the articular surface because the support for the volar and dorsal bone cortex has been lost. An extal fixator crossing wrist in combination with Kirschner wire (K-wire) fixation was popularly used by most studies in recent years. But loss of reduction often occurred especially in the volar sides. Methods A total of 30 cases of type C3 distal radius fracture were treated by a volar buttress plate combined with a transarticular extal fixator and other techniques such as K-wire fixation and bone grafting if necessary. The postoperative volar tilt angles, ulnar inclinations, radial heights, range of motion, grip strength and complications were recorded to assess the therapeutic effects. Results Of the 30 patients, 27 patients were followed up for 12-29 (mean 18) months and all fractures healed in 8-13 weeks after surgery (mean 10 weeks). The wrist function was excellent in 8 cases, good in 16 cases and fair in 3 cases according to the Sarmiento scoring system (modified by Stewart).Conclusions For type C3 comminuted fracture with severe volar and dorsal instability, fixation by volar buttress plate combined with transarticular extal fixator should be adopted. Dorsal instability could be further stabilized by other techniques such as Kirschner wire fixation, and bone grafting.