We compared Norian SRS, an injectable calcium phosphate bone cement, with external fixation in the treatment of redisplaced distal radial fractures by a prospective randomized study in 40 patients (women 50-80 years or men 60-80 years). After rereduction, the fracture was either stabilized by injection of SRS and immobilized with a cast for 2 weeks, or externally fixed with Hoffman's bar for 5 weeks. Each patient was evaluated at 2, 5, 7 weeks and at 3, 6 and 12 months. Functional parameters were grip strength, range of motion and pain. Radiographic parameters were radial angle, ulnar variance and dorsal tilt. The chosen primary effect variable was grip strength at 7 weeks. Patients treated by injection of SRS apatite had better grip strength, wrist extension and forearm supination at 7 weeks. There was no difference in functional parameters at 3 months or later. None of the methods could fully stabilize the fracture: radiographs showed a progressive redislocation over time. The results indicate that SRS can be used in the treatment of unstable distal radial fractures. The more rapid recovery of grip strength and wrist mobility in the SRS group appears to be due to the shorter immobilization time.