Radiostereometric analysis of distal radial fracture displacement during treatment - A randomized study comparing Norian SRS and external fixation in23 patients

In a randomized study, we included 23 osteoporotic patients with a distal r adial fracture and loss of reduction after 1 week. The fracture was re-redu ced. In one group, a self-setting hydroxyapatite, Norian SRS, was injected into the fracture and the wrist was immobilized for 2 weeks with a dorsal s plint (n 12). In the other group, the fracture was immobilized for 5 weeks with an external fixator (n 11). During the operation, the fracture fragmen ts were marked with tantalum markers, so that loss of reduction during the immobilization and after mobilization could be studied with radiostereometr ic analysis (RSA). We found some recurrence of compression in the fracture in both groups during immobilization. After mobilization, the motion of the fracture, measured by displacement of the fragments along the longitudinal axis, was less than 2 mm, except in 3 cases treated with Norian SRS. A com pression along the longitudinal axis of less than 2 mm is not likely to cau se any problem in the long term. From the first to the last investigation, 7/12 patients with Norian SRS and 4/11 with external fixation lost more tha n 2 mm of the reduction along the longitudinal axis. We conclude that 5 wee ks of immobilization is sufficient for healing with external fixation in th is age group. This immobilization time might be reduced to 2 weeks for frac tures treated with Norian SRS, but additional hardware should be used to en sure stability of the fracture system.