A biomechanical study of two internal fixation materials for rib fracture

TENG Ji-ping; YANG Zhi-yin; CHEN You-shuang; NI Da; ZHU Zhi-jun; PAN Tie-wen

Abstract：Objective To study the biomechanical characteristics of a new magnesium AZ 31B alloy intr-amedullary nail for treatment of rib fracture .This study was made to provide some biomechanical evidences for better clinical operation .Methods Thirty adult ribs were divided into 3 groups randomly ,and made models for the mid-dle fractures.The fractured ribs were fixed with AZ31B alloy intramedullary nail (AZ31B) and Poly-L-lactic acid intramedullary nail (PLLA),respectively.In addition,healthy ribs were taken as control group .The biomechanical test was performed and the stress was analyzed . Results ( 1 ) The bending strength of internal fixation with AZ31B was close to the control group (P>0.05);there was remarkable difference between PLLA group and AZ 31B group (P<0.05).(2) The torsion strength of internal fixation with AZ31B was close to the normal group(NS), but stronger than the PLLA group(P<0.05); (3) The tensile strength of AZ31B internal fixation was larger than the PLLA group(P<0.05);the anti-putout power of internal fixation with AZ31B was remarkably larger than the PLLA group(P<0.05).Conclusion The bending strength,tensile strength and anti-putout power of AZ31B are larger than those of PLLA.The internal fixation with AZ31B is an ideal method for treating rib fracture .