A BIOMECHANICAL ANALYSIS OF THE STABILITY OF TITANIUM BONE FIXATION SYSTEMS IN PROXIMAL PHALANGEAL FRACTURES

Apex bending and torsional loading were utilized to study the effects of different plate design and thickness, and screw size and design on the rigidity and strength of seven different titanium mini- and microp lates placed onto osteotomized proximal phalanges. One hundred forty-f our fresh frozen human cadaveric proximal phalangeal bones underwent a mid shaft osteotomy followed by application of one of the following p lates: (1) Synthes linear 1.5-mm five-hole plates, (2) Leibinger linea r 1.2-mm five-hole or (3) 1.7-mm four-hole plates, or (4) Leibinger th ree-dimensional 1.2-mm four-hole, (5) 1.2-mm eight-hole, (6) 1.7-mm fo ur-hole, or (7) 1.7-mm eight-hole plates, Three-point bending (apex do rsal or apex volar) and torsional loading were utilized for each plati ng configuration, Analysis of variance models of bone specimen width, depth, cortical thickness, and length revealed that increasing plate t hickness was associated with increasing rigidity, but that the three-d imensional design yielded a higher relative rigidity except under apex volar loading.