XWRAP Human Amniotic Membrane in Combination with an Amniotic-Fluid-Derived Biologic Promotes Collagen Fibril Regeneration in a Preclinical Rabbit Model of Medial Collateral Ligament Injury

Orthopedic ligament injuries are often treated with non-regenerative materials and surgical repair methods, rather than strategies that encourage natural tissue regeneration. A recent study investigated the potential of combining XWRAP, a human amniotic membrane allograft, with a cryopreserved amniotic-fluid-derived biologic containing micronized human amnion membrane to promote ligament architecture regeneration in a preclinical rabbit model of medial collateral ligament (MCL) gap-defect injury.

Four millimeter mid-substance MCL gap defects were meticulously created in New Zealand White rabbits, with three rabbits in each treatment group. One group was treated with the amniotic membrane/amniotic-fluid biologic combination, while the other group served as native controls with intact contralateral or adjacent MCL. The ligaments were assessed using transmission electron microscopy at 2 and 6 weeks post-procedure, with collagen fibril diameter being the key measurement taken from calibrated high-magnification micrographs.

The study found that the treated defects exhibited significantly larger mean collagen fibril diameters compared to the untreated defects at both 2 and 6 weeks post-procedure. Specifically, at 2 weeks, the treated defects had a mean collagen fibril diameter of 75 nm, in contrast to the untreated defects with a mean diameter of 50 nm (p < 0.05). Similarly, at 6 weeks, the treated defects displayed a mean collagen fibril diameter of 88 nm, compared to the untreated defects with a mean diameter of 62 nm (p < 0.05).