Biochemical, Mechanical, and Warping Behavior of Fresh Frozen Costal Cartilage Allograft

Background: Fresh frozen costal cartilage allografts are used in rhinoplasty, but their biomechanical and biochemical properties remain under-characterized. Objective: To determine whether cut orientation, harvest location, or irradiation status influences the biochemical, mechanical, and warping properties of a commercial fresh frozen costal cartilage allograft. Methods: Biochemical assays, three-point bending, and warping assessments were performed. Mixed-effects and linear regression models assessed associations with orientation, harvest location, and irradiation status. Intraclass correlation coefficients quantified donor-level variability. Results: Twenty-one specimens from 9 donors (mean age 43.1 years, 78% male, 44% irradiated) yielded 66 biochemical assays, 16 bending tests, and 143 warping observations. Collagen, sulfated glycosaminoglycan (sGAG), and collagen-to-sGAG ratio did not differ between cortical and medullary cartilage ( p ≥ 0.55). DNA was lower in medullary samples ( p = 0.02; ICC = 0.73). Elastic and flexural moduli did not differ by harvest location or irradiation status ( p > 0.35). Median 60-min warping angle was 8.15° (IQR 5.76–11.26°). Median plateau time was 37.2 min, with 94% stabilizing within 45 min. The 15-minute warping angle was the strongest predictor of final graft geometry (coefficient 0.917, p < 0.001). Conclusion: In this study, donor-level variation tended to exceed the effects of cut orientation, harvest location, or irradiation status.