Age and gender related changes in biomechanical properties of healthy human costal cartilage.

BACKGROUND AND AIMS For repairing the ear malformation, it is recommended in China to use the over than 10-years-old rib cartilage. However, according to our clinical experience, a better post-operation effect can be found using about the 7-years-old cartilage for the operation. To shape a harvested costal cartilage and to perform it on the transplant site depend on the mechanical properties of the costal cartilage. Hence, the aim of this study is to investigate the age and gender-related biomechanical properties of the human costal cartilage. METHODS Human costal cartilages were harvested from 25 female and 45 male donors of 5-25 years old after auricular reconstructive surgery. The specimens were divided into six groups: children (5-10 years), adolescent (11-17 years) and adult (18-25 years), respectively, in males and females. Tensile strength, stress-strain relationship, stress relaxation and creep were tested by using a material testing machine. FINDINGS The biomechanical properties of costal cartilage are donor age and gender related. The children group has the highest tensile strengths (P<0.01) in both male and female groups. The male group relaxed and crept more than that of the female group in all three age groups (P<0.01). INTERPRETATION These findings provide a further support for the potential age acting on the human costal cartilage. The adolescent has the lowest strength, this could be a reason that compared to using the children costal cartilage, the bigger distortion happened after using the adolescent costal cartilage in the auricular reconstruction operation.