The mechanical properties of costal cartilage of different genders and layers were tested, and the differences in mechanical properties of costal cartilage of different genders and layers were discussed. The theoretical basis was provided for the clinical use of costal cartilage of different layers in different situations, and the long-term effect after cartilage implantation could be predicted.

According to the inclusion criteria, from June 2018 to December 2019, patients who receive dauricle reconstruction with costal cartilage or supporting treatment with costal cartilage were collected from the Inpatient and Outpatient Department of Plastic Surgery of Sichuan Provincial People’s Hospital. The remaining central and marginal layers of the seventh costal cartilage were made into different sizes of cartilage blocks. The tensile strength test and compression test (including creep test and stress relaxation test) were carried out respectively. The counting data were described by the number of cases, and Fisher exact test was used to analyze the differences between groups; the measurement data were expressed by mean ± standard deviation, and the comparison between groups was analyzed witht-test.

A total of 28 patients, including 16 males, aged 12-24 years old and 12 females, aged 12-18 years old, were collected. In the tensile strength test, the tensile fracture rate of the central layer of costal cartilage in male was 87.5% (14 / 16) and that of marginal layer was 0, the difference was statistically significant (P< 0.001). The tensile fracture rate of central layer of costal cartilage in female was 83.3% (10 / 12), and that of marginal layer was 0, the difference was statistically significant (P< 0.001). In the creep test, there was no significant difference between the central layer and the marginal layer between 0.5 min and 2 min in men (t=-1.439, P= 0.171), and there was no significant difference between the central layer and the marginal layer in women (t=-0.731, P=0.480). In the stress relaxation test, there was no significant difference between the central layer of costal cartilage and the marginal layer in male (t=-2.053, P=0.058); in female, the stress relaxation in the central layer of costal cartilage was (0.006 ± 0.003)%, and that in the marginal layer was (0.011 ± 0.004)%, which was significantly higher than that in the central layer (t=-3.342, P=0.007).

The central layer of the costal cartilage in young people is worse than the marginal layer in tensile strength, and the calcification obviously weakens the tensile strength of the costal cartilage. Clinically, considering the calcification of the cartilage, the appropriate layer should be selected according to different parts and uses.

Costal cartilage; Biomechanics; Layer; Genders