Evaluation of internal fixation techniques for condylar head fractures: A finite element analysis and comparison.

OBJECTIVES

This study evaluated optimum stability of different screw techniques for condylar head fractures (CHF) (P close to an M fracture with the lateral pole preserved according to AO classification 2014) by finite element analysis (FEA) and provided a biomechanical basis for clinical treatment.

STUDY

DESIGN

Four CHF fixation models were evaluated: (A) single bicortical screw, (B) 2 bicortical screws, (C) 1 bicortical screw and 1 monocortical screw (used as a positional screw) inserted via a 2-hole titanium plate, and (D) 2 bicortical screws inserted via a titanium plate. Stresses were calculated (FEA) to measure mechanical properties.

RESULTS

The displacement for A and C was larger than for B and D. The maximum stress on the screws for A and C exceeded their breaking limit but was safe for B and D. The stress on the titanium plate for C and D was safe. The stress on bone for A and C was larger than for B and D.

CONCLUSIONS

The 2 bicortical screw fixation reduced the stress on implanted materials and surrounding bone tissue. Titanium plates further alleviated the lever action. Two bicortical screw fixation was more reliable for CHF, and early postoperative loading and functional training can be expected.