title: Osteochondral defect repair using a polyvinyl alcohol-polyacrylic acid (PVA-PAAc) hydrogel.
abstract: Poly(vinyl alcohol) (PVA) hydrogels can be candidates for articular cartilage repair due to their high water content. We synthesized a PVA-poly(acrylic acid) (PAAc) hydrogel formulation and determined its ability to function as a treatment option for condylar osteochondral (OC) defects in a New Zealand white rabbit (NZWR) model for 12 weeks and 24 weeks. In addition to hydrogel OC implants, tensile bar-shaped hydrogels were also implanted subcutaneously to evaluate changes in mechanical properties as a function of in vivo duration. There were no statistically significant differences (p > 0.05) in the water content measured in the OC hydrogel implant that was harvested after 12 weeks and 24 weeks, and non-implanted controls. There were no statistically significant differences (p > 0.05) in the break stress, strain at break or modulus of the tensile bars either between groups. Histological analysis of the OC defect, synovial capsule and fibrous tissue around the tensile bars determined hydrogel biocompatibility. Twelve-week hydrogels were found to be in situ flush with the articular cartilage; meniscal tissue demonstrated an intact surface. Twenty-four week hydrogels protruded from the defect site due to lack of integration with subchondral tissue, causing fibrillation to the meniscal surface. Condylar micro-CT scans ruled out osteolysis and bone cysts of the subchondral bone, and no PVA-PAAc hydrogel contents were found in the synovial fluid. The PVA-PAAc hydrogel was determined to be fully biocompatible, maintained its properties over time, and performed well at the 12 week time point. Physical fixation of the PVA-PAAc hydrogel to the subchondral bone is required to ensure long-term performance of hydrogel plugs for OC defect repair.
authors: Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, MA, USA. Harvard Medical School, Boston, MA, USA.
authors: David A
authors: DA
authors: Bichara
authors: Hatice
authors: H
authors: Bodugoz-Sentruk
authors: Doris
authors: D
authors: Ling
authors: Erik
authors: E
authors: Malchau
authors: Charles R
authors: CR
authors: Bragdon
authors: Orhun K
authors: OK
authors: Muratoglu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001847:Bone Diseases / Q000188:drug therapy*; D002358:Cartilage, Articular / Q000187:drug effects / Q000293:injuries*; D004548:Elasticity; D020100:Hydrogels / Q000737:chemistry*; D008297:Male; D008422:Materials Testing; D051379:Mice; D008810:Mice, Inbred C57BL; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D011817:Rabbits; D013056:Spectrophotometry, Ultraviolet; D013314:Stress, Mechanical; D013499:Surface Properties; D013582:Synovial Fluid / Q000378:metabolism; D013718:Tensile Strength; D014867:Water / Q000737:chemistry; D014945:Wound Healing; D055114:X-Ray Microtomography
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D020100:Hydrogels; D014867:Water; C006903:carbopol 940; D011142:Polyvinyl Alcohol