WURZBURG LAG SCREW PLATE VERSUS 4-HOLE MINIPLATE FOR THE TREATMENT OFCONDYLAR PROCESS FRACTURES

Purpose: The purpose of this study was to compare the biomechanical st ability of rigidly fixed condylar neck fractures using either a conven tional four-hole miniplate system or the Wurzburg lag screw plate syst em. Materials and Methods: Ten identical synthetic mandibles were used for this study, Simulated bilateral condylar neck fractures were fixe d with the lag screw plate system on one side and the miniplate system on the other, The mandibles were loaded with an MTS servohydraulic te sting machine at a rate of 1 cm/min until failure was reached, Data fo r resistance to motion and ultimate strength for each fixation device were compared by paired Student t-tests. Results: The mean resistance to motion for the four-hole miniplate was 64.0 kg/mm (SD = 10.1; range = 52-94) and for the lag screw system was 80.2 kg/mm (SD = 24.0; rang e = 55 to 126). The mean failure strength was 4.0 kg (SD = 0.9) (range = 2.6 to 5.5) for the miniplate system and 5.0 kg (SD = 2.5; range = 3.4 to 7.2) for the lag screw system. The lag screw system was signifi cantly (P < .05) better than the miniplate for both parameters measure d. Conclusion: In laboratory testing using synthetic mandibles, the Wu rzburg lag screw-plate fixation system proved superior to a four-hole miniplate system in regard to resistance to motion and failure strengt h, Clinical trials are necessary to substantiate these laboratory data and determine whether the system can be effectively applied by the su rgeon.