Early versus late reduction of a physeal fracture in an animal model.

This study was designed to determine whether delayed reduction of physeal fractures in an animal model causes growth disturbance, and whether final alignment is better in delayed or malreduced fractures. Salter 1 fractures of the proximal tibia were created in 41 immature rats randomized into five groups. The fractures were reduced as follows: group 1, immediately; group 2, 6 hours; group 3, 24 hours; group 4, 48 hours; and group 5, left malreduced. Both legs were analyzed for leg-length discrepancy, angular deformity, and evidence of radiographic bar. No radiographic physeal bar or leg-length discrepancy was seen among any of the groups. Angular deformity was greatest in group 5 and least in group 1. Immediate reduction resulted in the least angular deformity. Delayed reduction showed no evidence of physeal damage, physeal growth disturbance, or radiographic bar formation. Alignment was not improved in delayed reduction versus malreduced fractures.