A COMPARATIVE BIOMECHANICAL ANALYSIS OF RESORBABLE RIGID FIXATION VERSUS TITANIUM RIGID FIXATION OF METACARPAL FRACTURES

Linear (two-dimensional) and three-dimensional (3D) plating systems (P oly-Medics) composed of the resorbable copolymer of polyglycolic acid (PGA) and poly-l-lactic acid (PLLA) (Lactosorb) were studied in vitro, The plates were applied to osteotomized fresh frozen human cadaveric metacarpal bones that were then tested far torsional rigidity and thre e-point bending strength and rigidity, The results were compared to th ose from another study of two low-profile titanium plating systems (Le ibinger and Synthes), Analysis of variance revealed that the linear-fl at Lactosorb plate and screws had apex dorsal rigidity and force-to-di splacement measurements equal to all but two of the titanium plates (3 D). The 3D-flat Lactosorb plate had the highest torsional rigidity of the resorbable system, but it was only moderately rigid compared to th e titanium plating systems. This in vitro biomechanical study of the c opolymer PGA-PLLA plating system indicates that, in clinical applicati ons, it may be better suited for metacarpal fractures rather than prox imal phalangeal fractures due to the lower demands of torsional loadin g compared to apex bending.