Reinforced Polyester Patch Augmentation Improves Biomechanical Properties of Thin Fascia Lata Grafts for Superior Capsule Reconstruction

PURPOSE: To investigate the effect of reinforced polyester patch augmentation on the biomechanical characteristics of thin fascia lata graft. METHODS: Three graft types were made from fascia lata: (1) thin graft; (2) thin graft augmented with a reinforced polyester patch placed between 2 fascia lata layers; and (3) thick graft. Eight specimens per group were tested. Mean graft thicknesses were 2.7/3.0 mm (medial/lateral) for thin grafts, 4.4/4.1 mm for augmented thin grafts, and 8.6/8.9 mm for thick grafts. All specimens underwent cyclic loading followed by load-to-failure testing. Extension, hysteresis, linear stiffness, yield load, ultimate load, and energy parameters were compared using Tukey's post hoc test. RESULTS: During cyclic loading, no significant differences were observed among graft types in extension, hysteresis, or linear stiffness. The augmented thin graft showed the highest linear stiffness. Linear stiffness and ultimate load of the augmented thin graft (85.0 ± 4.4 N/mm; 1144 ± 61 N) were significantly greater than those of the thin graft alone (51.4 ± 5.6 N/mm; 435 ± 59 N) (P = .007, P = .01). No significant differences were detected between the augmented thin graft and the thick graft in linear stiffness (P = .08) and ultimate load (P = .97). CONCLUSIONS: Under cyclic loading, no significant differences were found among the three types of grafts in extension, hysteresis, or linear stiffness. In failure testing, however, the thin fascia lata graft augmented with a reinforced polyester patch showed significantly greater ultimate load and linear stiffness compared with the thin fascia lata graft, and these values were comparable to those of the thick graft. These results indicate that reinforced polyester patch augmentation enhances the biomechanical strength and stiffness of a thin fascia lata graft to a level equivalent to a thick graft, suggesting that this technique may provide sufficient initial stability for superior capsule reconstruction and serve as a practical alternative when harvesting or preparing a thick graft is technically challenging. CLINICAL RELEVANCE: Reinforced polyester patch augmentation enhances the strength and stiffness of thin fascia lata grafts, providing sufficient initial stability for superior capsule reconstruction and offering a practical alternative when harvesting a thick graft is technically challenging.