Measurement of Warping Angle in Human Rib Graft: An Experimental Study.

BACKGROUND: The purpose of this study was to determine the warping angle of the costal cartilage in vivo.

METHODS: A nasal framework reconstruction with a rib graft was performed in a total of 130 patients. After the cartilage specimens were prepared, the remaining grafts were used for study. The angle of warping in all grafts was measured at 0, 30, and 60 minutes; after 24 hours; and after 1 week. Eight subgroups of graft thicknesses from central and peripheral groups, determined according to the perichondral distance of the grafts, were evaluated, and the warping angles of 48 osteochondral and chondral grafts were measured individually. Three-way analysis of variance was used to compare the change in warping over time to detect differences in the grafts.

RESULTS: Significant differences were not observed in the 1- to 3-mm-thick grafts of peripheral and central origin before 30 minutes (p > 0.05), although significant differences were observed in these groups for all time points after 30 minutes (p < 0.05). In central and peripheral grafts thicker than 4 mm, a significant warping angle was not observed (p > 0.05). In central origin grafts thinner than 1 mm, significant differences were not observed in the warping angle (p > 0.05), although they were observed in the same grafts of peripheral origin (p < 0.05). Peripheral origin grafts thicker than 1 mm showed warping in the direction of the perichondrium (p < 0.05), whereas central origin grafts thinner than 1 mm showed warping angle irregularities.

CONCLUSION: Interlocking stresses are very important in rib grafts when balanced cross-sectional carving occurs from the peripheral to the central areas.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.