A comparison of combinations of titanium and resorbable plating systems for repair of isolated zygomatic fractures in the adult: a quantitative biomechanical study.

Multiple studies have sought to determine the postreduction stability of internal fixation in zygomaticomaxillary complex (ZMC) fractures. Three-point fixation with titanium miniplates is increasingly recommended to repair these injuries. Use of bioresorbable plates has been suggested to eliminate potential postoperative hardware complications. By quantitatively comparing different combinations of titanium and resorbable plating systems, this study attempts to demonstrate which combinations will provide stable fixation of the fractured ZMC. Osteotomies were performed on 40 zygomas in 20 fresh-frozen cadaver skulls, simulating noncomminuted ZMC fractures. The control group (group 0) consisted of titanium plates at the zygomaticofrontal (ZF) suture, infraorbital rim (IOR), and zygomaticomaxillary buttress (ZMB). Group 1 consisted of titanium plates at the ZF and IOR, and a resorbable plate at the ZMB. Group 2 used a titanium plate at the ZF, and resorbable plates at the IOR and ZMB. Group 3 consisted of resorbable plates at the ZF, IOR, and ZMB. A mechanical test system was used to apply loads in the vectorial direction of the masseter. Critical forces and patterns of hardware failure were recorded. Group 0 failed at a mean force of 589 +/- 146 N (60 kg). Group 1 failed at a mean force of 507 +/- 124 N (52 kg). No statistically significant differences between groups 0 and 1 were found. The mean force required for failure in groups 2 and 3 was lower. Differences in the force required for failure between groups 2 and 3 and the control group was significant (P <0.05). Failure patterns were analyzed. The ZF plate tended to stretch predominantly in groups 1, 2, and 3, whereas it tended to break in group 0 (P = 0.005). The IOR plate demonstrated predictable screw failure in groups 2 and 3 (P = 0.007). For group 0, the ZF was the site of the majority of critical failures. For groups 2 and 3, the IOR was almost invariably the site of critical failure (P = 0.004). At the ZMB, there was no significant association between failure modes and it was rarely the site of critical failure, regardless of the method of fixation. However, the strength of fixation was proportional to the number of titanium plates used. Overall, the method of fixation significantly affected the force required for mechanical failure of ZMC fractures (P <0.0001). The presence of teeth significantly increases the force required for implant failure in ZMC fracture fixation when combinations of plates are used (P = 0.038). All combinations of titanium and resorbable plates may be sufficient to overcome the displacing forces produced by the masseter and may be used for internal fixation of isolated ZMC fractures in the adult.