Purified collagen I oriented membrane for tendon repair: an ex vivo morphological study.

Purpose: Injured tendons have limited repair ability after full-thickness lesions. Tendon regeneration properties and adverse reactions were assessed ex vivo in an experimental animal model using a new collagen I membrane. Methods: This multilamellar membrane obtained from purified equine Achilles tendon is characterized by oriented collagen I fibers and has been shown to sustain cell growth and orientation in vitro. The central third of the patellar tendon (PT) of 10 New Zealand White rabbits was sectioned and grafted with the collagen membrane; the contralateral PT was cut longitudinally (sham-operated controls). Animals were euthanized 1 or 6 months from surgery and tendons subjected to histological and Synchrotron Radiation-based Computed Microtomography (SRµCT) examination and 3D structure analysis. Results: Histological and SRuCT findings showed satisfactory graft integration with native tendon; histological examination also showed ongoing angiogenesis. Adverse side-effects (inflammation, rejection, calcification) were never observed. Conclusion: The multilamellar collagen I membrane can be considered as an effective tool for tendon defect repair and tendon augmentation.