title: Mechanical testing of fixation techniques for scaffold-based tissue-engineered grafts.
abstract: Full-thickness defects in articular cartilage can be functionally restored by autologous chondrocyte implantation (ACI). In past years, numerous types of scaffolds for tissue-engineered cartilage implants have been developed and thoroughly characterized. However, the fixation stability of the implants has been rarely investigated despite its well-known importance for successful therapy. In this study, we have mechanically tested the fixation stability of four commonly used biomaterials for ACI attached by four different fixation techniques (unfixed, fibrin glue, chondral suture, and transosseous suture) in situ. Scaffolds based on polyglycolic acid (PGA) and polyglycolic acid and poly-L-lactic acid (PGLA), collagen membranes, and a gel-like matrix material were fixed within rectangular full-thickness cartilage defects of 10 x 15 mm(2) and loaded in tension until failure. Fibrin glue fixation of PGLA-scaffolds withstood a load of 2.18 6 +/- 0.47 N, chondral sutured PGA-scaffolds of 26.29 6 +/- 1.55 N, and transosseous fixed PGA-scaffolds of 38.18 6 +/- 9.53 N. The PGA-scaffold could be loaded highest until failure for all fixation techniques compared to the PGLA-scaffold and collagen membrane. Our findings serve as basis for selecting the most suitable fixation technique for scaffold-based tissue-engineered grafts according to the expected in vivo loads.
authors.affiliation: Institute for Biomechanics, ETH Zurich, Zurich, Switzerland. sknecht@ethz.ch
authors.forename: Sven
authors.initials: S
authors.lastname: Knecht
authors.forename: Christoph
authors.initials: C
authors.lastname: Erggelet
authors.forename: Michaela
authors.initials: M
authors.lastname: Endres
authors.forename: Michael
authors.initials: M
authors.lastname: Sittinger
authors.forename: Christian
authors.initials: C
authors.lastname: Kaps
authors.forename: Edgar
authors.initials: E
authors.lastname: Stüssi
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000473:pathology / Q000601:surgery; D002417:Cattle; D015718:Fibrin Tissue Adhesive / Q000378:metabolism; D048091:Guided Tissue Regeneration / Q000295:instrumentation / Q000379:methods; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry / Q000378:metabolism; D008422:Materials Testing; D010329:Patella / Q000033:anatomy & histology / Q000378:metabolism; D011091:Polyesters; D011100:Polyglycolic Acid / Q000737:chemistry / Q000378:metabolism; D011108:Polymers / Q000737:chemistry / Q000378:metabolism; D019736:Prostheses and Implants; D013314:Stress, Mechanical; D013718:Tensile Strength; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods; D019737:Transplants
chemical_list: D015718:Fibrin Tissue Adhesive; D011091:Polyesters; D011108:Polymers; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide)