EXPERIMENTAL-ANALYSIS OF INTERNAL RIGID FIXATION OSTEOSYNTHESIS PERFORMED WITH TITANIUM BONE SCREW AND PLATE SYSTEMS

The authors report the results of an experimental analysis performed o n titanium miniplates and screws in order to gain a better understandi ng of dynamic forces in internal rigid fixation, Ten segments of bovin e scapula were prepared, Osteotomies were carried out along the minor axis, following which five were fixed with four hole straight miniplat es and the other five with six hole double-Y miniplates, Each sample w as fastened in a special clamp adapted to a tension test machine and s hearing force was applied, Force versus time was recorded and the 50 b one fragments were examined by a pathologist. On the basis of the test results, two simple computer models were developed, No significant di fference was evident between the mechanical and computed tests. The mo st critical sections were located near the hole proximal to the osteot omy and the microscopic findings confirmed this, On the basis of the e xperimental results, the authors propose a new plate design in which t he area subject to most stress, proximal to the bone section, would be of miniplate thickness, the distal aspect being thinner as in a micro plate, It is suggested that this design would provide sufficient stabi lity and a high degree of anatomical adjustment of the system.